mn_vette

Ok, I just blew 2nd gear out of my 4th tranny in the last two months. I've got a 2200 stall converter, Manual lockup control on at 45mph, and a B&M tranny cooler. I had it built to handle some HP but things aren't going well.

All this is behind a newly rebuilt 396 made for torque, with a nitrous shot on top of it.

My mechanic that talks to the tranny guy said that he said that it was just the clutch packs. I picked up this tranny last friday and 2nd gear is gone already.

Do I just have to much HP? Is there anything I can do to fix this? What has everybody else done to make these things stronger? Oh, this is on a 4L60(no e). PLEASE HELP!!! I'm desperate!! :cry

86VETTEMAN

I don't have high HP but, I do know there are some guys using the 4L80(E). It handles a lot more torque than the 700R4 or 4L60(E). Hope this helps out.

jpee

I am wondering why you have it set to "lock up" at 45 mph.. several of us racers at E Town find our ET is about the same without locking up the converter..

By locking it you "might" gain 1-2 mph, but not any better ET..

IMHO I think locking the converter puts unnecessary wear on the trans.. After you get it running try it without locking it up...

mn_vette

Well, a few words Daily Driver Highway gasmileage Tranny Heat

I would try locking and not locking if I could keep the tranny in the car long enough to get to the track. I don't mean to seem harsh, but I'm jusr teally frustrated with the whole situation and I really don't want this tread to diverge from it's intended topic, how to make the tranny last. After that I'll worry about drag racing techniques.

As for the 4L80e I have looked into that but it seems to be about $4000 to do the swap with the tranny and the computer control module. I was hopefully looking for something cheaper.

Nathan Plemons

:iagree:

Now I don't have an auto tranny so this is just speculation but it sounds feasable. When the converter is unlocked there is some degree of slippage, allowing the tranny to do it's own thing independent of the engine. If the tranny has to slow down or speed up due to the shock of changing gears or something it can do so because of the "slack" in the converter. This does cause some inefficiency though because some of your engine power is going to the slippage doing nothing.

If you lock up the converter at 45 mph the tranny is essentially locked to the engine. If the tranny tries to shfit or recieves a shock from the rest of the driveline it can't just transfer this shock to the "slack" in the converter. It must absorb that shock because it's got the torque from the engine to overcome on the other end. Doesn't take a rocket scientist to figure out that something is going to break, and that will be the weakest point. That weakest point seems to be the gears in an auto.

So leave your converter unlocked when you are racing, OR delay lockup until you are in high gear. This way your tranny won't have to try and shift on a locked converter.

Just a thought but it seems rational, at least to me anyway. Again I don't know for sure because I don't have an auto. Take my theory as just that, a theory until anybody else can prove or disprove it. :cheers:

jburnett

From what I've heard the trick to getting a 700R4/4L60 to live behind high hp is how it deals with the line pressure as well as converter selection. I don't have a whole lot of experience with the OD autos with the exception of the one in my wife's '85 Vette. It runs a 475 hp 383 and runs 11.70's; it was rebuilt by a local tranny guru (Southern Transmissions) with Art Carr internals and a PI converter. I haven't had a bit of trouble out of it in a LONG time.. There are some builders out there who can build the OD's capable of running 10's and taking a lot of abuse, but they are few and far between. I'm well past those limits and I've made the decision to even pull my bulletproof ZF out and run my TH400...
-Jeb

Half Fast

My 4L60E is stock except for Yank 3000 converter, B&M 24k GVW tranny cooler and programming change to raise shift points to 6200 and a line pressure increase. The fluid and filter gets changed also. With a 100 shot I'm running around 460 RWHP and the tranny is still hanging in there. :chevy

dtorc4

I haven't had any personal experience, but I've heard many good things about Pro-Built trannys. I know ski-dwn-it is running one in his Vette, and has had zero problems with it (last time we talked about it, anyway). Ask him what he thinks. www.pro-built.net

FD2BLK

I would not drive a 700R without the converter locked up unless you like buying transmissions (Heat is the #1 Killer of OD transmissions).
Here is a good educational article on 700R TCs http://www.700r4.com/tech/tc_article/
Here is a link to a trany that will probably take care of your problem. A lot of my 4x4 friends have went with these transmissions because of the monster torque their trucks produce. There are a couple of good 700 builders out there but Bow tie is the only one I have any first hand knowledge of. Some people complain about the fact that they don’t like the fact they require you to use their set up procedure or they wont warrantee the transmission. I helped a friend of mine set his up and it was pretty much just checking the pressures at different times and setting the TV cable up, no big deal. http://www.700r4.com/trans/level2.html

mn_vette

Well, I talked to my tranny guy and he's been talking to Hughes and a few other tranny people and no one can give him a clue, he did everything they suggested to do.

I think he's finally fed up like I am, he offered me the 700R4 out of his dully pickup because he knows it works. he had it rebuilt last summer to handle all the towing torque that he puts on it. I figure I'll try it and if it breaks in less than a week like the rest I'll bring it back and figure out what to do after that.

jpee

>> would not drive a 700R without the converter locked up unless you like buying transmissions (Heat is the #1 Killer of OD transmissions).<<

I was running a Vigilante 3000 converter, & had 1.65-1.70 60' times consistently.. & I've had no problems w/my trans..

I do have a "GOOD" trans cooler.. & my trans temp NEVER goes over 210 deg. even if I'm hot lapping when we are down to 4-6 cars.

The Trans cooler.. is a MUST !!! I know there are 2 types of coolers, 1 is the tube with fins, & I cant think of the name of the other, but THAT is what I have.. & even with the 3000 converter in traffic it runs 200 deg.. & on a 90+ deg day on the highway when it locks up my trans temp drops to 180

As for locking up.. mine NEVER locks up during a run.. & it only locks up over 45mph, & when I'm NOT at full throttle.. I have a Hypertech programmer, & also raised my shift points, & raised the line pressure..

jpee

Oh..

I just remembered, my trans shop has told me it is NOT good to be always be making all out runs with the selector in "OD" he said it will kill 2,&3rd clutches.. if your gonna run it hard leave it in "D" not "OD"

I dont know how true this is, but I have been doing that with good luck..

red L98

hi i got my trans built by art carr they know their stuff give them a call at

1888-5265868 and ask for scott his cool guy and another thing i learned is

if u want ur OD trans to live longer dont let it down shift it self what i mean is

kick down and that they last for ever racing it off the line and its batter to

have a shift kit to alow u to down shift it urself going to 3rd then 2nd . when u

kick down it skips 3rd and goes 2 second and thats why u have problems with

it . i know i have 700r4 on a 415 stroker and 200 shot wet nos and it holding

real good thnks to artt carr and scott :thumbs: :grouphug:

FD2BLK

If you keep the trans in D and not OD then you can run as you stated with out the converter locking up and without heating the trany up.

mike 1985

There is a local guy here that has broke several well built 4l60 E's running 11.6-7 on motor and another that runs 12.20 and broke his too. I just don't think their that strong.

Since your going to try the 700 r-4 i think you'll be happier with it as we have several of those here running in the 10's

Corvette0096

http://www.pro-built.net :yesnod:

BowTieBlood

my t/a was faster in D than OD :cheers: , but i couldn't tell you why :jester


[Modified by BowTieBlood, 12:52 PM 9/25/2003]

ENGINE TROOP

i dont have much experience on high hp applications but my best advice is get a temp guage and put the sensor in the pan and don't let the temp get over 150 at any time. Also check your lines and flush the lines and cooler and install a new tc everytime you do work to your trannie ie. clutches.
also you can buy a magnetic inline filter from bowtie overddrives but this is ONLY for the breakin first 100-500 miles.
hope i helped

J Z06

John P

The name of the type of cooler in your car, ralphs and mine is "stacked plate" an RV cooler with some nutty GVW capacity.

mn_vette

The tranny cooler I've got is from summit

BMM-70264
24,000 GVW
11 in. x 6 in. x 1 1/2 in.
$49.95

Stacked plate