Since I’ve got my 03 ZO6 transmission out and am rebuilding it, I decided to inspect the torque tube and noticed that there is a slight amount of runout at the input shaft - maybe a half mm. Is this normal? I haven’t take anything apart; should I inspect further. I don’t want to spend money unnecessarily rebuilding it if I don’t need to.

 

So you have removed the input shaft from the assembly, and have it positioned on v-blocks(or equivalent) and have measured the runout that way with a dial indicator?

 

Chances are it's fine. The input shaft is supported by 2 bearings: 1) in the torque tube; 2) pilot bearing. If you have the torque tube out then the 2nd bearing support is absent. See if you can wiggle the end of the input shaft around, as that "looseness" is what will allow the pilot bearing to straighten it out.

 

For a C5/C6 Corvette torque tube input shaft, the generally accepted maximum allowable runout is around 0.002 inches (2 mils), though tighter tolerances like 0.001 inches are preferred for high-RPM performance, as excessive runout causes vibrations, and the pilot bearing helps, but significant wobble needs addressing to prevent clutch/drivetrain issues, often checked by rotating the shaft with a dial indicator or visual inspection against a fixed reference.

I had iirc .oo7 to .010 and fuked my pilto bearing up.

 

The input shaft is connected to the TT assembly. While the assembly is removed from the car, the input shaft has not been removed.

 

I cannot wiggle it where it’s noticeable to me.

 

I used a dial indicator and measured 0.031”, but this is with it connected to the TT. I tried to wiggle it, and it affected the dial indicator by anround 0.003”, so it has some wiggle room being that it’s not connected to the pilot bearing.
What bothers me is that I did not expect it to be out of round; I thought as I manually spin it, my eye wouldn’t be able to see the variance in the shaft, but I did see it. I just don’t know if it’s okay or bad - which means rebuild. I marked the side where it was 0.031 and marked the front where it was at 0, and they are opposite each other. In between, on either side, there is a linear increase or decrease. My conclusion is that somewhere along the assembly there is a slight bend; my guess is the dampener. One of you suggested since it’s not connected at the front/pilot bearing, it may not have anything keeping it aligned and it’s likely okay. With these recent measurements, does your thinking remain the same?

BTW: I have no experience taking on a trans rebuild and now a potential TT rebuild (and clutch kit too - that was planned along with the trans rebuild - since everything is out of the way), but I decided to start doing all maintenance/repairs because every time I’ve taken it elsewhere, it seems like I’m paying more to fix something others did wrong. I’m also tired of paying for the labor and markup. Nothing against the trade professionals, but the old saying “good help is hard to find” seems to apply in my experiences. The bright side is I’m learning a lot as I go, and I couldn’t do it without folks like you all helping with pointers and experience. So thank you for that.

 

Then you are chasing your tail. You cannot evaluate the runout of that part connected to the assembly unless you had some way to simulate the nose being contrained in the pilot.

 

When i checked mine it was off the TT.

 

Removed from the TT, I checked the propeller shaft; it’s runout was 0.007”. I separately checked the input shaft; it’s runout on a vee block was 0.003”. I suppose the guibos may explain the greater variance before disassembly. Speaking of, I had to use a propane torch to break the bolts loose. Had a few small flames and some smoke in the process. They look good; no cracks. The bearings turn smooth without any roughness and little noise. What stumps me is 1/4 (say 9 to 12 o’clock) of the bridge in the middle of the prop shaft is scuffed or maybe heat fatigued. Based on what I described, what is the perspective of the experienced folks? Is it necessary to replace anything besides the c clips/snap rings - I messed it up as it was stuck? What about bearings or other parts?