Michael_D

I need to drop the transaxle and swap out the clutch this winter. I’ve procrastinated that job long enough and just need to get it done. And I get to do it with the car on jack stands, joy-joy-happy-happy…..

Seeing how the bulk of the PITA work is getting the drive train removed and reinstalled, figured I might as well go through the tranny while I got it out of the car. I’m not a tranny guy. Rebuilt a few diffs and transfer cases, but never a tranny.

I absolutely hate first gear. Way too tall for me. I could care less about 60mph times. Gotta shift anyway when rallying about….. I’mt hinking about changing first from 2.22 to 2.97. With the engine mods I’ve doneso far, torque under 2500 is considerably lower than OEM, so a lower first (higher ratio) will help.

I don’t much care for 5th or 6th gears either. Again, too tall. Peak speed limit where I live is 65mph anyway.

Not being a transmission guy, I have no idea if I can just buy the gears I want and swap them out. I suspect there are physical limitations and good reasons why this is not an option.

Ideally, I think the following gear ratio might be more to my liking….

2.97/2.07/1.43/1.00/.80/.63

Or maybe….2.97/2.07/1.43/1.00/.82/.68 ???

Current ratio is: 2.66/1.78/1.30/1.00/.74/.50

I’m also not up to speed on shaft spline options. I see where many of the tranny shops advertise a 30 spline ‘upgrade’… What’s that all about?

If I’m not mistaken, I can upgrade to the carbon blocking ring set for smoother shifts. Any downside to this?

Looks like a bronze fork pads are another option. What are the OE fork pads, and what does this bronze pad option do for me?

Please school me on my options and what I consider doing to this thing. A good book recommendation on tranny overhauling would also be appreciated.

Unreal

30 spline is what a z06 is stock. Base vettes are not and need that upgrade for a z06/zr1 diff.

Not sure you can mix match 1-4 gears. I believe they are all on the same shaft. Can only swap the 5/6th to different. So you would have to pick a certain 1-4 stack, then a 5/6. I would talk to RPM and see what your options are.

Undy

Old post but might help...

https://www.corvetteforum.com/forums...or-c6-z06.html

Michael_D

Thanks for the input!

MTIRC6Z

I love the 2.97/2.07/1.43 ratios. But I'm not sure why you'd want something as 'short' as .63 for 6th though.

I got a RPM L5 TR6060 and L5 ZR1 diff brand new directly from RPM (but made the purchase through Ron at Vengeance for roughly the same cost as a new trans/diff, so the RPM upgrades seemed to be effectively free). I then sold my 'old' T56/Z06 diff to a guy who owned a C5 Z06. The RPM L5 trans shifts telepathically. Combining this stuff with some C5 axles, a RPS BC2 clutch and custom built halfshaft safety loops makes me feel like I have a built-proof driveline.

Cheers, Paul.

Michael_D

Thanks Paul. I don't use 6th. I'd have to cruise at 75 or better to not have surge. The cops round here keep an eye on my car. Not many like it around here..... Even 5th is a bit too high. Revs need to be 2200 or I feel an iritating miss.

Shipping costs for a tranny are horribly expensive. About a grand or more back and forth, because 2 day air is my only option. My local tranny guy is retired, and I don't trust anyone else. So I figured I'd do the work.

For anyone who cares, Tremec has the service manual for about every tranny they make on their website, but the 6060..... But, the car's service manual has it.

Can't find any "how to" type books for this sucker either.

Undy

Tune it in SD and you'll get rid of the miss. Ask me how I know...

Michael_D

Already tried speed density with MAF disabled....No real improvement. Also MAF only with SD disabled, no real improvement. I tried running this in Open Loop too. OL actually got rid of some of it (not all), but I do not like ignoring O2's so OL is not an option for me. My last experiment was to buy a larger CAI bridge, fit a honeycomb screen and recalibrate air models to reduce MAF hertz fluctuations (minimal improvement). My next, and probably last thing to try, is a newer ECM that will give me access to a couple more O2 tables.

It's not, as commonly phrased "in the tune". It's just what it is. If you're really bored, you can read all my efforts to deal with it over the last year or so here..... http://www.hptuners.com/forum/showth...%99m-desperate)

I may yank this cam out and try something different. Kinda depends on my motivation this winter, and if I need to pull the heads off again.

Dan_the_C5_Man

FWIW, I spoke to Rick Kim at RKT Performance yesterday, seems like a reasonable guy, plenty of good feedback from other forum members.. Another option for you (I know you mentioned shipping was a challenge).

You already have the presses and a few of the specialty tools you'll need, or do you plan on making those investments?

Michael_D

Rick/RTK is on my list of folks to call.

The challenge with shipping and related costs, have to due with the flight over and across Canada to get to Alaska. Doesn’t matter if the parts are in Florida or Washington, the costs are the same – stupid expensive. I had to pay $75 to get a set of pushrods sent the other day. I am a tool *****. If I don’t have what I need, I don’t mind buying it. I have a manual press and a magnetic bearing heater. Plenty of pullers, although I may need to get a couple more.

erick_e

Even though I am ASE certified and have lots of mechanical experience I was intimidated by the thought of rebuilding a T56.

With the right manual it was super easy. I'm sure Michael can handle it. Only special tools were some snap ring pliers and a gear puller.

I used both the Tremec manual and the GM ESI manual. I laid everything out a a large piece of cardboard with the sequence number so every step was documented by piece.

The hardest thing was drilling a hole in my workbench top for the shaft to fit in.

Dan_the_C5_Man

Gotcha.. I was going to ask, "Where in the heck are you, Alaska?" Now we know..

I played music professionally / full-time for a few years, did a short tour up that way and into Canada - man, those people were REALLY into their cigarettes.. I recall having to stand in the doorway of the club, with freezing temps outside and smoke billowing out of the club inside, just to try and catch a breath of fresh air..

I know a few years ago a CF dude wrote up a step-by-step teardown with pics of a T56, called out the special tools needed, etc. Not sure if it is still here or not. Was in the C5 tech section IIRC.

spode

Here is the link to the rebuild.
https://www.corvetteforum.com/forums...d-rebuild.html

double06

as you take it apart so you can remember. Rick at RKT is a good guy I have one of his transmissions.

Michael_D

Thanks fellers.

I don't look at the other forums much at all. Wouldn't be here if I didn't own a Z06.

That rebuild thread is excellent. A lot of effort went into it.

I have a background in turbine overhauls. Pictures and as found measurements are mandatory. I'll use the same approach.

Talked to the main Tremec OE parts supplier yesterday. Got some good info and advice.

Undy

I had a lot of experience with marine steam turbines, 400 to 1200 psi, 25,000 shaft horsepower. I did a few Kingsbury trust bearing setups too. A small amount of experience with GE LM3500 gas turbines too. Mechanical is mechanical.

MTPZ06

Which is it? Also, what air intake are you running?

Michael_D

Here's the engine highlights:

Comp HUC-R lobes. 235/255-113+3 - .650/.670
Halltech MF108
Fast 102; ported.
NW 102
Ported heads with Crower rockers.
Smith Brothers .120 rods.
Morel 5293 link bar lifters.
ARH 1 7/8 LT's
ID 1000 Injectors
MSD coil packs, with direct 12v harness.
NGK TR7ix plugs .055 gap.
High amp billet alternator (forgot the model)

SHovV

I've ALWAYS read and heard bad things about the MSD coils. Have you tried stock coils to see if your odd misfire issue goes away?

Unreal

And a smaller gap? Never seen a LS motor run that gap. Also agree on the MSD coils. Also why the upgraded injectors? You running e85? I would put stock injectors, stock coils, and some different plugs in it first.