gongshow71

iTrader: (1)

After destroying 2 pilot bearings and 2 input shafts over the past 10 months I came to the conclusion that I have a serious alignment issue with my input shaft/clutch set up/pilot bearing.

After doing some research I learned that its vital to perform parallel and concentric alignment on Tremec T56 transmissions. I spoke directly with Tremec and they said not doing so voids the warranty on their transmissions and that it should be done on every install.

Example:


According to their T56 service manual Tremec recommends aligning the the input shaft within .010" in "face and in bore." If you're out of spec it will put a side load on the input shaft which will lead to input shaft bearing wear and failure, or pilot bearing failure which is what I am having problems with. To fix this you have to shim the bell housing to fix the parallel (aka "face") and then use offset dowel pins to correct the concentric (aka "bore").

From my research, some high performance builds even recommend having the parallel alignment within .002" and the concentric within .005". This seems over the top to me if Tremec says .010" is fine but what do I know at this point.

To do it properly for a T56 you have to remove the front cover of the transmission and mount it to the bell housing to have a surface to measure on. The T56 bell housing doesnt have any way to measure it without putting the front cover on.

After spending 70+ hours under the car on my driveway I have given up and bought a 2015 Civic Si for a daily, but I refuse to sell this Trans Am. I can't get reliable measurements and have decided that I am going to leave this up to someone with much more experience than myself.

Can anyone recommend a shop in the DFW that is trust worthy and methodical that can help me out? I am worried about allowing a shop to do something that I cannot verify their work until 5000 miles down the road my input shaft goes out again and there's no warranty on the work done by them because its a performance shop.

Thanks!

This is how I was measuring parallel:



And concentric:

chrysler kid

iTrader: (14)

Who is building your transmissions. I Have done several in the dark and never had a problem. Including the car in my signature

Call Texas drive train performance and talk to Jason. You're not rebuilding them correctly or your builder is not doing it correctly

gongshow71

iTrader: (1)

I've only ever used Jason @ TDP and he has done great work for me. I'm even using his stage 2 Diamond clutch with 15lb light weight fly wheel which I love by the way. That's why I'm convinced something is going wrong with alignment somewhere within the bell housing.

Today I called Anything Automotive in Denton as well as RPM Transmissions and both of them said the never do bell housing alignments on LS/T56 set ups. So I guess I'm just going to put it back together and hope for the best. If they're building 1000+hp drag cars then I shouldn't be having any problems with my 400hp street car that stays below 5500 rpm.

txazformula

iTrader: (8)

So I have to wonder how GM ever did this in a production environment without voiding Tremec's warranty requirements

gongshow71

iTrader: (1)

I've tried to wrap my head around this as well because there is no way they could have done it on a mass production line. I'm just going to put it back together and see if it breaks a third time. If it does I have no idea what I am going to do.

ramairetransam

iTrader: (18)

maybe your bellhousing is fucked up , i never knew you were supposed to measure like your doing . I dont know anyone who has done that or had the issue .

chrysler kid

iTrader: (14)

Are you using a pilot bushing or pilot bearing? Are you using a poly trans mount or a stock one, I strongly reccomend a stock rubber mount to reduce internal stress,

Are your motor mounts all new"ish" ?

I'm running a stage 2 tdp t56 Julian built for me from a core in the shop. I'm also running a stage 2 diamond clutch with a stock weight flywheel. (I think it's stock, I told him I needed parts for my six speed swap and he grabbed a cart and started grabbing parts for me lol)

I'm not thrilled about your lightened flywheel, I haven't done the research on it but I'm assuming others have done it without problems?

Jason reccomended pilot bearing (he sold it to me) and also sold me new flywheel bolts and shims for the clutch. I think the whole process of draining Jason brain of knowledge and Julian building my core took 3 hours. That was years ago though

My stage 2 chattered like hell when it was new. With a light weight flywheel I'm wondering if you are running a poly trans mount and chattering the **** out of that pilot bearing. The rubber mount will wiggle and transfer more of the vibration out of the trans than a poly would. At one point I remember the chatter causing extreme bangs and clunks the first week or so on the poly mount

It may be worth a try to switch to a pilot bushing if you have only been using a bearing.

gongshow71

iTrader: (1)

Pilot bearing which is what Jason, RPM, and everyone else recommends to use. And a Energy suspension poly urethane mount.

Motor mounts are 120k miles old and trashed. About to replace with energy suspension poly urethane.

Jason sounded thrilled about the light weight fly wheel and recommended it so I'm trusting him that he knows its safe to run.

I'm putting the car back together this weekend so I will go from there and update once it breaks again... if it does... hopefully not!

Bowtie316

iTrader: (1)

I had a tight pilot bearing hole in my crank that caused me problems with the stock bearing. I ended up turning down a pilot bushing that fit better and so far so good. I will mention though that most of the new bushings are hard and not oilite like intended.

00pooterSS

iTrader: (40)

I would recommend a new bellhousing and a stock flywheel, rubber trans mount and poly eng mounts.

In my opinion there are more downsides to light weight balancers and flywheels than upsides. Back 20 years ago when I was in the honda world I saw a lot of oil pumps being blown apart due to light weight crank pulleys (they need to be heavy to absorb shock and prevent harmonic vibrations, in other words harmonic balancers are heavy for a reason). For that reason I would personally stick with a stock flywheel, the weight wil help reduce harmonics and it helps with launching, I get that the light weight one helps with acceleration, but to me it doesn't make a big enough difference to offset the downsides. That and I trust the machining/centering more than with aftermarket parts.

I would definitely ditch the poly trans mount. And I just realized you are using a poly trans mount with stock engine mounts. If I recall correctly some people have reported trans case damage from that setup, the engine is flexing and the trans is trying to be completely locked. That will put a lot of stress on the trans housing.

Put in poly eng mounts and a new factory rubber trans mount and enjoy less broken parts and less cabin noise too

Again, I would highly recommend a new bell housing, yours may be tweaked and don't be surprised if it has something to do with busted old engine mounts and the poly trans mount.


For what it's worth I've stabbed several T56s without issue, and honestly I didn't take any special steps, just threw them in like any other trans. See if you can also get new dowel pins, maybe one is a hair off or bent.

Also check your oil pan and make sure it is sitting flush with the block/trans bell housing. It's all designed to work together

chrysler kid

iTrader: (14)

Jason all recommended the same to me, but after reading stories about the poly trans mount causing cracked tail shaft housings I went back to rubber.

If your factory mounts are shot and the trans is sitting on the basically solid trans mount it's transferring that rotational stress back up into the engine.

So you're having to release the clutch at higher rpms because of that light weight flywheel, causing more stress on the back of that crank. That stress is usually dampened by a heavier flywheel, like I mentioned that ceramic disc chatters like he'll when new, and it's all getting shot back onto the crank back into the engine. You have yet to mention how bad the stage 2 chatters, it's something everyone complains about with the stage 2. I'm sure if you could see your engine at clutch release you would see it shake like badly with those blown motor mounts

Fyi it took about 700-1000 miles to break in my diamond stage 2. It was very sensitive to a quick clutch release and would chatter the driveline so bad my trans would hit the body under the car. (I have spohn solid mounts that raise the motor about 2 inches) with the poly trans mount it would chatter the *** of the ten bolt so badly i knew it would destroy a u joint or worse eventually. It's gone now, the clutch is awesome, releases like stock and immediately sticks on a power shift through the gears

I'm not thrilled with light weight flywheel on a daily driver either, but I don't think it's specifically the cause of your problems

So my advice is to go to solid motor mounts or poly motor mounts and a stock trans mount.

If the trans is pulled it makes things a little easier to get to those motor mounts

Just another reference, we installed a pro 5.0 shifter in a buddies car a few years ago and his motor mounts were so busted that the stick alignment wouldn't even let him get into reverse because the shifter would hit the dash. So those blown motor mounts definitely affect the angle of the transmission under the car

gongshow71

iTrader: (1)

All of this definitely makes sense. I appreciate the input guys! I'm putting the poly engine mounts in this weekend and will try to find my OEM rubber trans mount. Ill hopefully have the car back together next weekend. Once I put some miles on it (or it brakes again) I'll report back. May be a few months though since its a weekend car now.

00pooterSS

iTrader: (40)

Best of luck to ya man

adanieljohnson1

iTrader: (1)

Great shop!!! I did his Stage2 T56 with his stage2 diamond also.. I loved my V when I had it...