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Hello everyone. I'm in the process of rebuilding my T56 for my 01 C5Z. I've gotten to the shimming process. I've but the input, main, and counter shaft together and got the case on with no shims to check for end play. Right now I have .000in of end play without shims. I've replaced all bearings/races and I have a 8620 forged steel mainshaft. Everything is seated properly as well. Is this okay with the new bearings? This is my first time rebuilding a T56. I've gone through the manual to see of I might have messed up and I haven't. I even went as far as disassembling everything and put it back together.
Last edited by TxPete20; Mar 26, 2024 at 12:10 PM.
St. Jude Donor '08-'09-'10-'11-'12, '14-'15-'16-'17-'18
If you have replaced all the bearings and races, make sure the races on the main case are seated all the way. Of all the T56 I've done, I never had one that didn't have play on the main/counter shafts.
I just reshimmed a box I'd previously. I was not happy with the inconsistency that I got in my readings before. I used this method to help draw the line where zero preload is.
I added .012" to the input/main and .007" to the cluster gear to get what feels by hand to be as close to 0 on the input/main as my shims allow and .001"ish preload on the cluster gear. There's no question my races were seated the first time I did this. The kicker? Prior to disassembly I had no perceptible endplay, so I have no idea where to begin to understand how I could be so far off and think I'm right.
If you have replaced all the bearings and races, make sure the races on the main case are seated all the way. Of all the T56 I've done, I never had one that didn't have play on the main/counter shafts.
I made sure all races were seated. I used a feeler gauge to check and make sure there was no gap.
I'm incredibly suspicious that OP is encountering something similar to what I did. I HIGHLY recommend adding the thinnest shim you have and see if that induces preload. If it doesn't, keep going until it does so you can truly see where 0 is. Using this method, as I got a thou or 2 from 0, the shaft (either one) would have a noticeable amount of rotational resistance (which I initially mistook as preload) that would go away once you gave the shaft a few spins.
Might be a silly question, but when you're measuring endplay, is the trans horizontal or vertical? When I rebuilt my t56 I saw a significant different in numbers based on where gravity was pulling the shaft.
By the book it should be vertical with the input facing down. I have seen YouTube videos with folks laying them down and measuring. I wouldn't recommend that.
Might be a silly question, but when you're measuring endplay, is the trans horizontal or vertical? When I rebuilt my t56 I saw a significant different in numbers based on where gravity was pulling the shaft.
Not a silly question, but you want it standing vertical to measure for endplay
Hey guys bringing this thread back from the dead. What shimming spec did you guys use? So far I have two sources that contradict each other on the mainshaft.
The Tremec T56 manual available online states the following specs:
XP’sGarage video series on YouTube is the same except the mainshaft he PRELOADS to .000-.002”(I think he says he uses the 04 Corvette service manual). I also saw some places just aim for .000” on all three shafts. Any suggestions from people that do this often? Appreciate it.
Hey guys bringing this thread back from the dead. What shimming spec did you guys use? So far I have two sources that contradict each other on the mainshaft.
The Tremec T56 manual available online states the following specs:
XP’sGarage video series on YouTube is the same except the mainshaft he PRELOADS to .000-.002”(I think he says he uses the 04 Corvette service manual). I also saw some places just aim for .000” on all three shafts. Any suggestions from people that do this often? Appreciate it.
Nobody I've spoken to has ever been on board with the endplay on the main shaft. My suspicion is that Tremec was trying to keep the little pocket bearing alive that lives between the input and the main. As for the end play on the counter extension, that one's lost on me. I've always chickened out on preload on the main and just shot for as close as I could get to 0. If I ever were to replace the bearings it would be preload everywhere as they do loosen up with use. The PDF manual doesn't specify a difference for new vs used bearings. Breakaway torque might also be a viable alternative here.
Thanks for the info. I actually have a digital copy of a service manual for a 2003 Corvette and it says .000-.002" of PRELOAD on the main/input shaft and countershaft, and .002-.005" of ENDPLAY for the countershaft extension. I attached the excerpts here... I don't know why they are showing to the measurements upside down for the mainshaft and countershaft extension, but whatever. These are the specs I will use.
I am going to do it without the 5-6 cluster. Doing it with the 5-6 cluster would be a bad idea in my mind. You would have to press the compound gear on, do your measurement, then pull it off to be able to add the shim again. Lots of extra work and you are potentially wearing down the splines on the gear or the main shaft.
I am going to do it without the 5-6 cluster. Doing it with the 5-6 cluster would be a bad idea in my mind. You would have to press the compound gear on, do your measurement, then pull it off to be able to add the shim again. Lots of extra work and you are potentially wearing down the splines on the gear or the main shaft.
Not the 5-6, the cluster gear is the countershaft.
T56 shimming
