4+3 trans swaps
 

i have an 86 4+3 car w/ missing trans, wich transmisions are swappable? i was thinking about a 5 speed from an 82-92 f body. if i remember correctly those cars use a simiular tourqe arm. anyone ever tried a regular rear trans crossmember?

welllll..

I considered that, but bailed due to time.

The T5 out of an fbody uses the same clutch, same flywheel.

Question I couldn't get answered was bellhousing. If you mate a T5 to a Fbody bellhousing you get the same length as a 700R4, so you can use an auto/dana36 driveshaft + cbeam.. I don't know if the T5 will make to the 4+3 bellhousing. If you can solve the bell housing mystery, then on to the next step.

As far as the Cbeam / torque arm goes that should be VERY straight forward. Infact, the fbody tail shaft has bolt holes for a torque arm mount. You should be able to mill out of a block of aluminum a Cbeam mount that will bolt right to the tail shaft.

Now once you have the bolt pattern/bellhousing issue, and Cbeam issue resolved we are left with only 1 remaining problem. The T5 shifter is in the dead center of the tranny, and might not be where your 4+3 hole is. (could be too far forward or back, and most likely to the right). That you're gonna have to figure out on your own. Now you can probably cut the shifter in 1/2, and weld a offset plate to it to correct that issue.

If you want to measure your 4+3 bellhousing (if you have one) distance from block surface, and bolt pattern spacing, i'll get T5/fbody measurements and we can at least determine if the T5 will bolt up.

-- Joe

Go with a ZF6, It will bolt up with minor adjustments.

If you just wanna get the car on the road, there's a 4+3 for sale with everything attached to it still in the for sale section of this site for $800.

If you really wanna swap a trans in the question becomes how much money you got? I personally wouldn't go with the ZF swap. They're really expensive to rebuild and if you buy a rebuilt one by the time you're done getting the other parts for the swap you've spent as much as swapping in a Keisler. The Keisler trans is my favorite choice for going into the vette. Check out their website at www.keislerauto.com for details. It's pricey, but it is a direct bolt in and their trans's are always first-rate quality.

If you really want to have a go at some custom work (either you can't afford a Keisler or you have a lot of time on your hands) there is an adapter for sale at www.prostreetcustoms.net for bolting a C-beam to a T56. The T56 from an LT1 Camaro has the shifter the right distance from the bellhousing, but you need to make a custom coverplate because it sits to the right an inch or two.

For the T-5 and anesthes other questions, I'm pretty sure the T-5 will bolt up to a 4+3 bellhousing.

Here's a T-5 Bellhousing:
http://www.fbodymotorsports.com/inc/sdetail/8098

And here's a 4+3:
http://www.vetteweb.com/tech/vemp_05.../photo_11.html

Bolt pattern look the same, as were most GM transmissions for many years. The shifter should be in about the right place as far as distance from the bellhousing because you can swap an LT1 T56 into an f-body and the shifter is in the right place, and you can swap that same T56 into a C4 and the shifter is in the right place except side-to-side.

If you have some time on your hands and/or access to a cheap T-5 (there are lots of them) I'd say give it a shot. Know that you will definitely need a custom shifter cover cause the shifter will be half-way into the cupholder. I would likewise be interested if you go ahead with this.

Lots of money for a one off, not very good transmission. Big money flywheel and clutch. Big money tranny that was only used a few years.. I say T5, or T56 is the best route.

And before some expert chimes in with power handling figures, I've run faster times in a boosted bird than a majority of CF members with a T5 setup with no problems. T56 would be slick for the 6th gear though.

-- Joe

Untrue. This swap will cost you about $2400 with a new tranny or $1500 with a used one, including the new clutch and bell and hydraulics.

There is very little clutch selection though and I don't like the clutch design. But compared to the other "bolt-on" options, Rich6 and TKO, you have to consider it for the price.

Whoever told you the trans is "not very good" is full of :bs

I didnt spend very much for my 4+3 to ZF swap... used the 85 flywheel, so it wasnt big money, and the clutch came with the trans...

So far, I love it... the gear clatter isnt that bad either. :thumbs:

I've driven them. They are not a good trans. Compared to a T5 or modern T56, they just drive silly. The shifter is weird, the whole thing just doesn't feel good. My opinion. Plus if you brake one, good luck getting it fixed cheap.

$1500 for a used manual transmission setup is insane. You can buy numerous 5spd's for that price. I really think corvette owners need to start thinking out of the box. I see a HUGE difference between thirdgen.org and this place.

Just my 2cents.


-- Joe

It "drives silly"? You sound like you're talking out of your ass.
:rolleyes:

A used ZF goes for $750-$1000. Read carefully, the $1500 includes a NEW clutch set, NEW clutch master & slave, hose, used bell and driveshaft.

I don't appreciate your insults. I guess nobody is using the T56 because we're all ignorant.

Or maybe its because the T5/T56 won't work easily in the vette due to shifter location. So until you or someone makes it work with a new shifter or tailhousing, or a new console, you're pissing into the wind.

First off, I've never insulted you. Infact, i've backed you up in another thread when someone else was stomping on you. I'm not sure how you could possibly take my post as an insult.

I don't like the way the ZF drives. I feel like your getting insulted because I don't like the thing. I think it feels goofy. I've built and driven a ton of non ZF cars. This is the first tranny I've hated.

Perhaps I'm 'pissing into the wind'. I didn't do the swap. But i've done numerous auto to stick swaps on other cars. If you want to check thirdgen.org, you'll find posts as far back as '99 of me doing stuff that others say couldn't be done. I just don't understand why nobody wants to try anything new around here. I stated how I think it could be done. I don't have the time to try it right now.

-- Joe

Sorry, I don't own stock in ZF Industries or care what he decides to put in his car. I just don't like seeing people spread BS information. The ZF is a legitimate (and cheaper) choice and by saying otherwise you are limiting this guy's options.

Since you are apparently sold on the T56 and are so talented at doing these swaps, then why don't you do it? If it's so much better and cheaper, you won't have a problem selling custom parts for the conversion to make it worth your while. But you act as if you're the first guy to think of it.

Whatever. I'm trying to help. the guy asked about using a T5. I answered him. Seems like the only acceptable solutions around here are the easy ones. I dissagree with your point on cost, but you don't seem to welcome any other opinion. So I'm done with this thread. I hope the original poster got the answers he was looking for.

-- Joe

You also have another option; you can replace the 4+3 with the Richmond 6 speed.

Here's the product description:

Just an FYI, a lot of people say the gears are noisy with this tranny. I personally don't know because I'm still running with the 4+3. I only threw this tranny on here to give you one more option to look at.

Joe,
We are not supposed to post ebay links here from what I understand but.....I have a complete and working Doug Nash 4+3 set up listed for $300 that ends in a couple days. Just thought I would throw that out for another option. I'm doing the ZF swap and I'm in for 3 grand w/ mostly new parts + used bellhousing / clutchfork / master...etc
:cheers:

3K sounds a little steep. How much did you pay for the trans?



Joe, I also have a 4+3 for sale, it needs a new overdrive front seal though. I'll probably just put one in if nobody wants it as is.

Hi Central,
1450 +150 s/h for the new tranny then add the Ram conversion (clutch/pp/al FW and hyd.throwout bearing)=1100, used bellhousing,master cyl,pinion yoke=330. Add a longacre ss line@ $30..........:willy:

T5's are really weak- GM wouldnt even put them behind L98's in the camaro, so steer clear of that- any of the other trannys are good, though (no matter what some people are trying to tell you)

I have a paper weight on my desk that is an old T5 3rd gear. I had a mustang running in the 12's and blew 3 of them up. You can call Liberty gears and ask them. I was thinking of the ZF6 swap but they guy that we buy or trans stuff from just told us to rebuild the 4+3 as it would be as strong,lighter,and a whole lot less complicated. He's got 30 years experience so we a rebuilding the 4+3. Just my .02


AL

mrc, I missed the part about the RAM conversion clutch. With that setup, you've got the weakest link taken care of, IMO (and are still under the cost of a bolt-in TKO or Richmond kit.)

I'm guessing had you swapped to the ZF this guy wouldn't be making any money on the deal. The 4-speed is very stout though, I'm not sure why so many people knock it for power handling. Of course it won't hold up being abused in overdrive, but which trans does?

trans
 

imho
normal driving, use the overdrive
non normal driving.........don't touch that button until it's almost wound out and the torque is almost gone

Well we are going to make the OD and on demand system and not an on request system. Then at least I can clutch in/out to save the OD. With a 3.54 and 25.6'' tires 128 mph is all you get out of 4th and that is 5900 rpm at that.

5900 is wwwwwwwwaaaaaaaaaaaaaayyyyyyyyyyyyy out of the power believe me!! Only throwing the switch on real long straight away's. With us normal use is the track! That's about it.

The 84 and 85 were all "on demand" overdrives. It's a shame GM screwed with it beyond that, they have no one to blame but themselves for the 4+3's reputation.

:iagree: ZF-6 Trans-plant, along with the C5 brake upgrade, is the best change I ever made on my 84. Can't beat an internal rail shifter especially when coupled with Hurst shifter.

A GM V8 T5 has the same bolt pattern, spline and same length input as the ST10 4 speed used on the front end of the 4+3.

The beam thing however is not that easy...but with good fab welding skills it can be done.

They are in fact (I know first hand) noisy but brutally strong. I still have the Richmond. It has about 100 miles on it. For sale! (whole kit).

Just how noisy are these things? That's what I am planning to switch mine out to if the 4+3 ever goes out, which I don't think it will. Luckily for me, the previous owner completely rebuilt it about 5,000 miles back.

GRX, what are you looking to get for the kit? PM me.

Actually it has less than 100 miles on it. A trip to Santa Cruz from San Jose and a few times around the block!! 1st, 2nd, 3rd.... sound like a reverse gear...not as bad but enough to anoy me. Kit was from Eckler's:
Tranny, shifter, speedo sensor. Let me estimate a price. Will PM.

I was thinking rather than weld, mill a bolt on mount. The T5 with bell housing should be the same length as a 700R4. Looking at my setup on lift last night, compared to a T5 tail shaft I think a block of T6 can be milled for the verticle holes to the cbeam, and horizontal holes and depths to mount to the tail shaft. I figure just measure the driveshaft pinion angle of my current 700R4 setup, then set the lift up so it's resting on the mechanical safety's, and use my screw jacks to hold the T5 and dana in the correct spot so the same pinion angle is achieved. Then it's just a matter of hand milling and taking the peice on and off and on and off and on and off until it's the right size and holes are in the correct spot.
Once that's done, a 12-pack and a pizza for my buddy and he can write a CNC program for the part I make by hand.

Once that's done, all folks would have to do is bring the program on floppy to a CNC machine shop and pay for materials and a run on the machine.

That of course cures the cbeam issue. I'm still concerned about the shifter.

I can't do any of this now, it's spring but, once it gets cold again (november), I'll start playing. I have access to a T5 for mock up, just need the 4+3 bell housing, and I have a bunch of alum blocks and a small vertical mill in my shop. If nobody else does it between now and then, i'll start tinkering. Might happen sooner if my 700R4 blows up before then.. If so I really hope I can get *some* of my $500+ back on the torque converter.. :(

-- Joe

has anyone swapped a T-56 into a C4? Everything Ive read says its way to complicated to bother with.

Complicated eh? Hrmm.

Only thing that concerns me about the T56 is the dimensions. Will it be too long, will it hit the exhaust, etc. The T5 should be more 'direct' as it bolts to the 4+3 bellhousing, is same length, etc.

Guess it's something to look into.

-- Joe

yeah when I referred to complications...I was speaking to fitment issues. :cheers:

There is atleast one guy on here with a T56 in his C4. The size is fine. The only real complicated part is making a custom shifter cover cause the shifter is too far to the right. Gotta use the LT1 Camaro (93-97) bellhousing, clutch slave, flywheel, etc. Forget his name, but do a search in the C4 tech forum for T56.

I wonder what ever happened to this and why it didn't come to market?

http://forums.corvetteforum.com/show...hlight=Keisler

Yeah but we dont use it much and I had just pulled the relay up to this point but some tracks will require more top end so this will suffice. And BTW the diffrence between the ZF and the 4+3 rebuild, for us, was time and money. I rebuild my spare tranny for $200 and still have another spare to rebuild for the next time I need one. The ZF is quite heavy as well. The guy that advised the rebuild over the replacement only sold me a cluster shaft and 1-2 shift cam. about $200 for both. He's also a very resourceful and respected name in racing in the detroit area. For some reason I really like the gearing and the way it works in the car.

Al

By welding I was referring to fabricating a bracket. Since you have the original 700 or 4+3 why not just simply take some measurements and fabricate a bracket. The milling thing seems exciting and trick but.... take a good look and those lower bolt holes. It is much easier to take a 3/8 thick STEEL plate and make some spacers so that is it fastened to those holes, then do a 90 degree plate by weld on the top and bottom. Add some steel tubes for the beam bolts in between them to prevent the upper and lower areas from crushing. Take that off and have your beer buddy make a solid piece out of billet for resale to the hundreds of people who will want to do this conversion.

There is a BIG problem with people using tailhousings not designed to carry the load of these beams by use of brackets and other rigs. If the tailhousing flexes the bushing will wipe out. A T5 typically runs less then .003 of bushing to yoke clearance. The Mustang tail for example has holes that were used to mount dampner weights for harmonics while the T5 Camaro tail is better gussetted because it was designed for a trailing arm attachment.

Thats why i was thinking of using an Fbody T5, because the fbody uses a torque arm to keep the rear end from twisting on launch and decel, so it should in theory be able to handle load. Infact, I think on a C4 application is would be under a little less load as the rear end doesn't rotate.

I'm not impressed by my 700R4/transgo/raptor combo, so I'm pretty sure this fall I'll take the trans out, and start a stick conversion. I'm kinda kicking myself in the ass for selling my lightweight flywheel, clutch setup, T5, etc last year.. Oh well.

-- Joe

Actually the rears on these do rotate. Some guys running high HP and slicks are twisting the 3rd member up and the torque beam is snapping the snout off. I doubt this would ever harm the trans though. It probably seems more forces at the end of the trans when bottoming out or hauling over dips in the road, when the weight of the engine+trans is bouncing around, held up in back only by the torque arm bolts.

Does the Fbody torque arm bolt to the trans or the chassis? Have any pics?

I mean rotate as in part of the design, I know with enough force it sure will :)

The fbody torque arm bolts to the tail shaft of the trans, the fbody tail shaft differs from the mustang in that it has 3 bolt holes for the torque arm mount. (this is why i'm so confident in retrofitting a T5).

The transmission ALSO has a crossmember mount on the tailshaft itself (not the tranny) that is used as a rear engine/tranny spoort. When the car is driven, the rear end wants to rotate up and down so the tailshaft keeps it from rotating. The torque arm is similar to the cbeam on a C4, except that the cbeam is fixed, and the tailshaft is designed to move around. It's really a crappy design, but thats another story.

The tailshaft on the T5 is very similar to the TKO, infact, a lot of fbody guys replace exploded T5's with TKO transmissions.

Here is a few pix of a firebird I built right before I bought the C4. It should give you an idea of how the T5 setup in a fcar works. (this car was parted when I bought the vette cuz they're work more in peices)

http://members.cisdi.com/~anesthes/f-car-t5/23.JPG
http://members.cisdi.com/~anesthes/f-car-t5/24.JPG
http://members.cisdi.com/~anesthes/f-car-t5/27.JPG

Generally speaking, T5's are dirt cheap, and can be built to handle 500hp/tq (http://www.fordmuscle.com/archives/2...ild/index.php), so they could be a good replacement for a 4+3 IF the cbeam + shifter can be adapted.

As far as adapting the shifter, rather than cutting out the console I've seen shifters cut and welded so the handle is offset 2" to the left. (used on some 4x4 applications, and one guy on a T56 C4).

-- Joe

I don't get it, if the trans is bolted up to the torque arm, then the whole trans would have to move with the suspension travel.

Are you sure that torque arm isn't simply a trailing arm, and that there's a joint up near the trans where it pivots? If this is the case, then there is no torque exerted on the tailhousing of the T5. I agree that the C4 setup is too heavy to work well as it's designed. The most telling part is when you compare it with the C5, the C5 with rear trans puts less bending from weight on their torque tube and attachment points, not to mention it's way beefier.

Viper used a nearly identical setup to the C4 layout, I'm not sure if they moved the motor mounts back more, or have some extra support on the trans though.


On a side note, why is the floorplan trashed? Is that from jackstands?

NM I see from the pic that there is no upper control arm, so that beam you're referring to is simply there to prevent axle wrap.

More like a third member. Without it, the rear end will rotate. What normally happens to a thirdgen/fourth gen (same setup) when you hop it up, on launch it will break the tranny mount and the tranny will slam the tunnel every time you gas it. Pretty funny, and scares the crap outta the driver the first time it happens. Theres TONS of pressure being put on it, which is why a lot of guys go with a solid mount, Then after that an aftermarket tubular arm because the stamped steal one bends. If you look at the pics, you can see mine was bent to crap from racing with slicks. Again, it's a crappy design.


I kinda like the C4 setup. Maybe because I never had one before last year.. A few guys have retro'd the dana in a thirdgen. waste of money..

More than likely. I hammered most of it out, but it still looked kinda bad. Subframe connectors to stiffen it, then undercoated the whole thing. Built the car first supercharged, ran it, then n/a, drove it once after that but I had been itchin to get a C4. My cousin bought a c4 like 5 years ago and I had driven it a bunch of times, then my buddy bought a '91 ZF6 car that I drove a lot, did a clutch job and a few other things n, etc. One day I got up at like 6am, went down to the shop and by 8pm had the whole car apart and everything recorded in a notebook for ebay. Bought a C4 about 3-4 weeks later at an auction.

Anyway, to get back on topic, I think T5 in C4 will work.

-- Joe

Your camaro rear is nosing up and the beam is trying to lift the tail end of the trans, this isn't torquing the trans since it's free to pivot at the trans, as you mentioned the trans hitting the tunnel when the crossmember breaks.

Imagine how much worse it'd be if there was no crossmember, and you simply bolted the beam rigidly to the trans.

Now the diff nosing up is going to torque the hell out of the trans casing, and the weight/momentum of the drivetrain sagging/bouncing is going to torque the hell out of it also. None of this happens on the Fbody. You simply need a stronger crossmember.

I wouldn't expect the T5 case to last on the vette simply based on it's setup in the Camaro.

Sorta yeah. It is in a rubber joint so it has some play, but it does put a lot of pressure on the tail shaft. Like i said, it breaks tranny mounts.

Welll. For the fbody application it wouldn't work becuase it's a live axle. If the rear end was stationary like on a c4, than i'd think it would be less pressure. You're making your driveline static, even your driveshaft never changes angle with bumps.

After thinking it through, I think it would be fine. And after seeing both the Keisler, and T56 I know it won't be a problem.

-- Joe

The Keisler uses the two lower crossmember holes and puts them in torsion to hold it up. Whether or not that works for them without killing the cases, time will tell.

Even with the Stock C4 setups the trans cases deform and output seals leak in back when overtorquing the cbeam bolts.

Starting the swap. Gonna do a T5. Stay tuned.

So far the Theory is:

4+3 Pedals and master
Howe hydraulic TOB
T5 out of an fbody
Custom cbeam adapter plate

Bell housing still up in the air.

-- Joe

Keep us posted, this will be a cool swap.

6 months later, you are looking for zf 6 tranny parts, anesthes

No I'm looking for 4+3 parts (bell housing, pedals, hydraulics). Using a T5 and modified shifter/adapters.

CentralCoaster and I have gone back and forth on this in a pretty detailed fashion in PMs, and he's been very helpful giving me measurements and his 2 cents and experience in doing his ZF swap. Other members such as LD85 have also given their insight. I've done all the calculations and it appears I can do the 700R4 to T5 swap using a lot of 4+3 parts as well as some fabricating for around $1100.

If of course, things blow up in my face, I will be sure to post my results. Either way I'll be posting and letting you guys know the progress. The 700R4 came out last night, and the motor comes out tomorrow. Once I've negotiated with a seller of the pedals and hydraulics, those will go in, and then after a cam change the motor will be back in along with bellhousing. I need to locate a decent T5 and a hurst shifter so I can made an adapter for the Cbeam and start on the shifter rod adapter.

The T5 and 700R4 use the same yoke, and the distance from the block to the tail shaft is the same, so they use the same length driveshaft.

I've taken all the critical measurements down prior to unbolting the 700R4 so I can be sure the pinion angle will be the same with the Cbeam adapter I will construct. When completed I will post the specs and measurements of the adapter, as well as materials. It will be made from 1/4" plate steel and mig welded together.

-- Joe

I just wish someone would come up with a bellhousing to bolt to the back of the LS and bolt up a ZF. :toetap:

If you really want a 6spd, go with the T56 swap. It's stronger and there are more of them available than the ZF6.

I don't want another war, but I will state the facts. The T56 will bolt up to an ls1 of course, for $199 you can get the tailshaft adapter from pro street unlimited so now it bolts to the Cbeam.

If you have a L98, you can get a wier bellhousing which allows bolting of a stock T56, to a an SBC with traditional flywheel + clutch setup.
(you can use the 4+3 stuff!) It uses a hydraulic throw out bearing, so it's clutch agnostic.

A T56 swap is even better than a T5 swap in terms of strength, and the additional overdrive however I'm 100% positive it will cost more than a straight up ZF swap. ($500 for bell housing + tob, $199 for cbeam adapter, $whoknows for tranny, $250 for a good 11" flywheel, $300 for a good clutch, lots of time and patience).

I'm going with the T5 because the cost of ownership is lower, and I can break about 4 of them for the price of one ZF or T56. I can't use any lower overdrive than the T5 has to offer unless I re-gear my rear-end, or put a stock cam back in it. If I need more 'clutch holding power' I can step up to an 11" clutch by using an aftermarket OR Muncie (think 70s) bell housing + hydraulic throw out bearing.. But I've had pretty good luck with the 10.4" clutch + t5 combo in the fbody's so it should work fine in a lighter car.

-- Joe

I made the change to at-56 about2yrs ago in my 86. There where only 2 choices zf6 or t-56. After listening to all the guys with syncro problems and the cost to repair the zf6 I went with a t-56 set up out of a 96 camaro . 550.oo out of ajunk yard for everything. It was alot of work but with the help from Tom at Pro Street Customs who makes the kit to connect the tranny we got it done. Im running around 500 rwhsp and dont baby it. The trans is great and solid as a rock.:cheers:

That's dirt cheap. Mind posting step by step how you did it? A lot of folks have problems with the hydraulics. Do they clear the long tube headers ok, or did you use a hydraulic TOB ?

What did you use for a clutch master cyl? A lot of thirdgen guys find the fbody master in the thirdgen doesn't push enough fluid to work the fourthgen slave.

-- Joe

Yes, but if you already have a ZF-6 in the car, the economics make the case pretty convincingly.

the clutch slave is pretty close to the headers so I wrapped them with a good heat wrap---no problems. I used the stock clutch master with alittle mod to the line. works fine.

True. I was thinking more along the lines of guys with 4+3s, or even 700R4's.

I saw some new ZF's on ebay for $1300. thats cheap.

-- Joe

Sooo..

A company called "pro street customs" specializes in weird vette stuff. They make a cbeam adapter intended on folks whom wish to put a T56 into their C4 corvette.
They sell this thing for $150

http://www.prostreetcustoms.net/site...56-404x266.jpg

http://www.prostreetcustoms.net/site...l1-548x712.png

Well, GM iwhen they designed the 4th gen they didn't want to redesign the torque arm mounts and such, the T56 and T5 tail shafts appear to have the same mounting bolt pattern. Which means, for $150 the cbeam mounting issue could be resolved.

So I think:

1) new flywheel
2) New clutch
3) Used 4+3 BH,
4) Used 4+3 pedals + hydraulics
5) Cbeam adapter
6) Hurst fbody T5 'offset' shifter
7) Used T5 transmission (v8)

The offset shifter is designed to compensate for the 18* rotation of a fbody bell housing. The shifter base can be taken apart, and the mount reversed so now the shifter will lean over to the drivers side 18*. Then you just heat up the rod that bolts to the mount on the press, and turn it a hair to center in the hole.

Not bad for a 700R4 to T5 swap. If it works.....

UPDATE:

I spoke with Tom who owns pro st. He wants some measurements, but he told me worse case scenario, if I ship him a T5 tailshaft he will modify the adapter and start producing them for T5 swaps.

Again folks, a T5 will bolt the 4+3 bell housing. If you have a 4+3 that blew, this could be a solution for only a couple hundred bucks.

-- Joe

Awesome, I have a 4+3 and ya never know when it will take a dump. It will be cool if this works so I have an alternative.

Who says the ZF bellhousing won't bolt up to it? The block bolt patterns are the same.

Everyone should read this before knocking the T5. The T5 and 10.4" clutch aren't first on my list, but that's why it's cheaper. The ring/pinion costs is also an excellent point.

I put a ZF6 in front of 3.07 gears and all I got was a useless 6th gear and a too tall 1st gear. The upgrade to 3.45s cost me another $400 (and headache) in addition to the $1600 spent on the ZF conversion.

I like to see anyone putting the work in to open up the options for everyone else.

Another update.

It's Official. Pro Street will be offering T5 cbeam adapters, and I'll do the final 'writeup' on the swap. A T5 tail shaft is on it's way to Pro street for mockup on the Jig.

Once I get the prototype cbeam adapter from Pro Street I'll snap a billion pix for everyone. I don't know what the turn around is right now, but I'm considering summer over so I'm in no rush. My vette will stay on my right bay lift until this project is complete.

I'm doing a 700R4 to T5 swap, but for folks with a 4+3 this will be a more 'direct' swap. I chose to use the 4+3 BH and hydraulic setup because I think that will be the more likely scenario for folks, and most direct. (Folks replacing worn 4+3 transmissions).

The drive shaft WILL BE THE SAME, the T5 + 700R4 share the same yoke. Apparently the 4+3 yoke is the same too..

As far as clutches go, for a few years now I've been using clutches from Fort Worth Clutch. They sell a 2200lbs pressure plate and 'dual friction' knockoff clutch for about $165 shipped, that has more holding pressure than a centerforce and the same or better quality. Contact Scott at Fort Worth clutch for specific requests. (He will do custom pressure plates/discs if needed).

If you need a new flywheel, kajunjon-whitneytx transmissions offers a 16lbs lightweight flywheel for $173 shipped. It's about as light as you
want to go for a street flywheel, and surely better than having your old flywheel turned.


-- Joe

What happened to using the Fbody bh and rotating the T5 for better shifter location?

The only benefits I see for you on the 4+3 bh is saving 4+3 owners from buying a $25 junkyard part, and getting to use a 10.75" clutch. But you already said you were using a 10.4" clutch.

:lurk:

I believe they are the same but I've never seen the 700R yoke.


Spline count and yoke OD are the same.

Driveshaft p/n's for '84 auto and 4+3 are the same. (only year where both had same rear end)

Driveshaft p/n's aren't same for 85-88, but I suspect that's because of the change to D44, which is longer.

The ZF-6 BH won't fit with the LSx FW which is necessary in order to engage the starter at its location on the block.

How big is the LS flywheel/clutch?

Does it move the starter further away?

Can the starter be move inwards?

I looked at the blocks side by side but didn't check that.

Your PM box went full so I couldn't update you on that. :)

The Fbody bell housing hydraulics won't clear the exhaust like you suggested. To make it work, you need to saw off the slave cyl mount, and run a hydraulic TOB for a T5 ($165 + shipping), which won't work
with the master cyl, so you need a 3/4" bore master ($73 + shipping), hoses ($25 + shipping). You also need to make sure the master you get has a travel stop, or you have to buy a pedal stop to keep from blowing the seal on the TOB.

Yeah I'm gonna use a 10.4" clutch probably. I couldn't find any part #'s on the 10.75" clutch for the 4+3. (for the flywheel rather). Any scoop on that?

-- Joe

That clears that up I think then. They won't need a yoke... Great!

-- Joe

From a previous thread

More info i found from some F-body stuff:
-LT1 has a 153 tooth 12.75" diameter flywheel
pull type with slave and pivot fork

-LS1 has a 168 tooth 14" diameter flywheel
push type with hydro throwout bearing

So the mounting pad for the starter on an LS motor is .625" further out than on SBC and FW too wide to fit under BH.

Why can't you use a 10.4" clutch and pressure plate, since it's a hydraulic TOB ? That would let you use the 153tooth starter.

-- Joe

Great thread..

Thanks CC and Anesthes

You guys start out fighting and then collaborating. :rofl:

sometimes a bit of discourse leads to a solution

For what it's worth, Astro Performance sells heavy duty gear sets and beefed up T5s that can handle 550hp/425 ft lb of torque ($1,650). These are intended for Fords, so I don't know if it is the same as what would work with GM. I know stock T5s are always a weak link at least with 5.0s (third gear can break). That would be my concern with running a T5.

http://www.astroperformance.com/prod...roducts_id/209

4+3 Problems - Experts please
 

I wanted to get your expertise on a problem I am having with an 1984 Corvette Doug Nash 4+3.

1) All gears shift smoothly without noise or grinding.

2) Overdrive works well

3) Transmission pops out of 2nd gear while decelerating.

Questions:


I have had people tell me it could be motor mounts or worn transmission mounts. How much travel should I have?

Should I have the Doug Nash 4+3 repaired / rebuilt? Cost?

Purchase a good working Doug Nash 4+3?

Automatic Swap? Low cost option? How difficult? Parts needed?

Swap for another manual?

What are my best possible solutions?

Please help:crazy:

Spoke with pro street today. They're almost done the cbeam adapter for the T5. Should be done by the end of the week, then they will be sending me the prototype.

Once I get it i'll put everything in place and snap some pix, and write up a short 'how to'.

-- Joe

T-5
 

What is the estimated cost of replacing the Doug Nash 4-3 with the T5?


I am looking forward to see the write up on this conversion. Thanks for all the effort guys!

Gonna depend on how much you get a T5 for. I got mine at a swap meet for $50. I was offered about 5 more locally for $200 each, and will probably buy another as a spare. Figure $200-250 for the T5.

I'd expect the Cbeam adapter to be about the same cost as the T56 adapter, figure $150-200 for that. So lets say $450 so far.

The Fbody shifter is offset. It can be modified for about $40 at a welding shop if you can't weld, OR you can get a hurst pro-comp shifter. Thats $165 new. Need to take it apart, and put a lever in the other way. I have not got to the shifter part yet, but the stick is probably going to need to be cut, and offset about 1.5-2" and welded as well. if the 1.5-2" offset scares you, go look at a 60s mustang. The offset is like 8", or a 80's mustang at 3" :)

So worst case scenario $650 or so, if you get things cheaper, do things yourself closer to $500. You can do it as cheap as $350 if you can modify the stock shifter yourself.

-- Joe

anesthes - Thanks
 

Joe,

Thanks for all your help. I have a 84 Corvette with a Doug Nash 4+3. I checked the OD filler for fluid. I believe I found gear oil. Or dirty ATF oil.

Could 80-90w gear oil from the gear box be transfer to the Overdrive section of the Doug Nash 4+3?

Joe, I like your idea of using a T5. I want to keep the cost down and have a dependable transmission. On my 84, I can reuse the bell housing, hydraulic slave setup, flywheel, clutch disc, pressure plate and drive shaft. The 84 driveshaft in the same for automatic and manual.

My swap will need a fbody v8 T5 manual transmission, shifter and cbeam.

Please let me know on cbeam too

Does this sound correct? Again thanks for your help.

A ZF-6 swap is much more direct and probablyt costs less. I did one on my 84. Great swap. Its a whole different car to drive.

Dominic Sorresso - ZF-6 swap
 

Hi Dominic,

I live about an hour north of Rockford IL. I believe a need to replace the Doug Nash 4+3.

You have an 84 Corvette too! What will I need to perform the swap? Parts list? Modifications? What can be used from the 84 Corvette? Any sugguestions are very welcomed. I am very interested in learning more.

How does it drive now? What do you like about it?

Rick

A ZF6 swap isn't more direct. You have to change the hydraulics, bell housing, flywheel, clutch, transmission. On a T5 swap, all you have to change is the transmission. The tunnel mods are the same.

And the costs are not even close. Like I said, worst case scenario $650, but more likely closer to $500 - and if you break a T5, you can get replacement transmissions for under $250 all day.

The ZF is surely stronger than the T5, and if you have a tall enough rear end gear you can actually use the 6th gear off the ZF6. If you're worried about strength + having 6 speeds, your much better off going with a T56 which is also a direct bolt in using a Cbeam adapter from pro-street.

You can't go near a ZF for under 1k.

ixlor8: You need a T5 + cbeam adapter. You can use the stock Fbody shifter with the T5 (need to modify it) or an aftermarket shifter (still need to modify it). Your bell housing, driveshaft, clutch, hydraulics, and cbeam will all be the same.

Thanks Joe. I will be looking for a T-5. I would like to keep the cost down. I am going to keep the stock engine, so horse power is not an issue.

Do you have to do any changes for the speedometer?

About how many hours does it take to take out the Doug Nash 4+3 and replace with T-5?

Thank you very much for your help, :bigears

Speedo is a very good point. You will of course need to change the plastic drive and driven speedo gears in the transmission, for a total cost of about $18.00. (you won't find an fbody with a 2.59 rear end). Depending on the year of your vette, and year of the T5 you need to make sure you get the right VSS. If yours is cable, an 82-86 firebird/camaro VSS. If its 2 wire magnetic, an 87-89 firebird VSS. If its optical, 90-92 camaro/firebird.

As far as 'hours'. Not sure. I have a lift, tranny jack, stands, etc. You need to:

Disconnect battery
Remove the distributor
Lift vehicle
Put a stand under the oil pan to keep the engine from diving
Unbolt the driveshaft
Drain transmission/od fluids
Unbolt exhaust
Disconnect any wires, cables, linkage
Unbolt the cbeam
Unbolt the transmission

Probably about 3 hours with a lift + air tools. I had an automatic,
which came out in about 2 1/2 hours. But I'm doing cam too, so I also yanked the motor.

Looking for a T-5
 

Joe, I must say you have been a great help.

I am in the process of looking for a T-5.

Which transmission years should I be looking at?

'83-'92 V-8-powered Camaro and Firebird
1982-1992 Chevrolet Camaro (World-Class T-5 with RPO code MK6)
1993-2002 Chevrolet Camaro (V6 models) ?? Torque ratings lighter?

Rick

Any updates on this swap? I'm ready to do this right now if it works. Thanks-Charlie

Part Number Chart - 1984 to 1995 Corvette
 

Joe,

Is this information you wanted? Clutch / flywheel and more.



http://home.san.rr.com/khastings/ima...hpartslist.gif


Rick

Man, I really wanna do this swap now too. I've got a 4+3 and it's only a matter of time till it's done now that the 383 is up and runnin'. Since I've already got a 4+3, I can leave my bellhousing and clutch on the car and the trans will bolt right in, right? If I can weld the shifter properly it will come out in the stock location? And with the C_beam adapter from ProStreet Customs it will fit the C_beam with a few modifications. Does the driveshaft need to be shortened? This might finally be an economical alternative to the 4+3...:party:

93-02 won't work. You need a 82-92 camaro/firebird out of a V8. The world class T5's are better. Dont buy the first one you say, hold off for the right price. Junkyards want $300+.. Most local guys parting out cars get around $200.

I'm just waiting on the prototype cbeam adapter. Assuming I get it this week, i'll bolt it up and let pro street know if any changes need to be made. If not, I imagine they will be available almost immediately.

The shifter needs to be cut and welded so it comes up in the right spot.

The drive shaft should not need to be altered. Same yoke, and same length.

I'm not 100% sure on cbeam mods yet. With the T56 swap, you need to drill two new holes because the back of the tranny is weird, but on the T5 you should be able to make the bracket work with the stock cbeam holes. But thats pro streets part.

-- Joe

That sounds awesome, keep us all posted on how that adapter works out. I'm gathering parts as we speak :cheers:

Holy smokes guys - reading all of this makes my head spin - seems like alot of work to save a few hundred bucks! In my 86, I just went with the Keisler TKO500 - made the swap in a day and a half - drives and shifts great after 2 years of abuse on road tracks - no issues to report!

Great gear ratios - of course I have it linked to a ZZ4 - so that may make some difference!

I'd much rather drive my car than work on it. For me, the extra money was worth the saved time and potential headaches! I could devote all that extra time to other projects I am working on! So instead of fooling with the Transmission in the car - I was building my Bonneville racer and going racing every couple of weeks with the 86. (the one with the TKO500)

Everyone is different - we all have different priorities, and skills I guess thats what makes it so much fun!

Carl "satisfied Tremek customer" Johansson

Carl Johansson

Carl,
I see where you're comin from, but it isn't a few hundred bucks. The cost of this T5 swap is about $3000 cheaper than the TKO kit. In a car like my 84 that's worth maybe $6-$7k, spending $3700 on a trans isn't what I want to do. $700 for a new trans is much more to my budget right now...

You obviously haven't read all of it. We're talking about a swap that will COMPETE with keisler but will only cost a few hundred bucks instead of $3k.

The 'headaches' will be exactly the same, since it's the same thing. Same basic transmission design (externally), same type of cbeam adapter. Same tunnel mods. The only 'diy' part will probably be the shifter, and even then
maybe we can work something out with pro street to mod stock fbody shifters on a trade-in basis.?.

The TKO is a nice transmission, like the ZF, like the T56, and so on. It's a matter of what you need. Considering the values of C4's have dropped like a rock, now that you can get into a C5 for under 20k, it doesn't make much sense putting a very expensive transmission in a C4.
If and when you decide to sell or trade the car in, nobody is going to give a rats behind that you spent 3k+ on a TKO..

-- Joe

Mine's an 84 with the 4+3 currently. Which VSS is it, the 2 wire magnetic or the optical? How can I tell? Also, mine's got the 3.07 rear right now. Anyone know what rears most Camaros came with?

Electrical Connections on Doug Nash 4+3
 

I have a 1984 Corvette shop Manual.

I see six electrical connectors, and Throttel valve cable on the Doug Nash 4+3:

1) 1st Gear Switch connector

2) 2nd gear switch connector.

3) 4th gear switch connector

4) Overdrive Solenoid Connector

5) E.S.S connector. Electron Speed Sensor

6) Backup light switch.

How do we handle the 1st gear, 2nd gear, 3rd gear and overdrive solenoid connectors on the T-5? Will we get an error code if they are disconnected?

E.S.S connector plugs into the overdrive unit of the Doug Nash. How do we connect this to the T-5 I do not see a speedometer cable it must be electronic.

Throtte valve cable - This cable is on the overdrive unit. This must act the same way like an automatic transmission. I do not think it is used on the T-5 because it does not have an overdrive.

Sorry for all the questions.

Richmond 6-Speed Corvette Installation Overview
 

I found this website last week. It tells the story about replacing the Doug Nash 4+3 with the Richmond 6-speed. Very interesting.

http://www.areddy.net/vettetrans/

Rick

Tach - function with the T5
 

I am guessing that the tach gets it signal from the Electronic Speed Sensor.

Where do you find the adapter for the plug in from the factory harness to the T-5 transmission?

It's magnetic. Camaros came with all sorts of rears. You'll need to probably buy the two plastic gears. You'll need a magnetic VSS for a T5.
Should be fairly easy to come by.

i'll post pix when I get a chance.

ESS/VSS + backup switch will go to the transmission. The plugs are very standard with GM. (two wire post type).

No throttle valve cable needs connection.

As far as the solenoid connectors, you won't connect them. I'm not sure if you will get a code. I'm going to have to defer to someone whos had some experience with that end. On my '87 i'm running a computer from a '91 fbody (1227730) because I like MAP better than MAF for tuning.


-- Joe

Tach - function with the T5
 

I have been told that it comes from the distributor.

Tach comes from the distributor

You will not get an error from leaving any of the gear switches out. My first gear switch has been bad on my 4+3 for a while and I bypassed it and it's been fine. You can probably remove all the gear switches.

O.D. Solenoid connector will be useless and can be removed.

ESS/VSS and Backup light will work fine. If they need adapting cut the plugs off the junkyard donor for the trans and solder them in.

TV cable can disappear cause it will now be useless