I removed my tranny and replaced my 3-4 clutches with a Z-Pak set. I've worked on my transmission many times, so I have good experience tearing it apart and re-building. However, now I have a constant vibration, while driving and even while sitting at idle. It gets worse when I rev it. Not sure what to look for. The flywheel is relatively new, and there was no vibration before replacing the clutches.

Any thoughts on what to look for when I remove it?

 

I encountered a similar issue with a rebuild too. Couldn't figure it out until I learned about GM's transmission vibration test procedure. Yes, it's in the 86 Camaro GM factory manual.
As it turns out, if the torque converter isn't reinstalled exactly as it was relative to the flexplate, the stack up of balance tolerances can induce a vibration where none existed previously.
The manual suggests re-clocking the TC to the flexplate by 120 degrees. Then test. If the vibration persists, go another 120.
It worked for me. I had neglected to index the parts when removing the transmission.

 

Thanks for the response. Yes, I've re-clocked the torque converter twice, nothing changed.

 

Can't say what if anything went sideways in the trans. I had thought that my transmission rebuilder had dropped the thing and bent something.
Is there a possibility that the flexplate is the issue? Balance pad vs neutral balance perhaps? Of course if it's the same FP before and after then that's not it obviously.
I've read accounts where an externally balanced FP can be installed incorrectly relative to the crank if the locating dowel isn't in place. But that's truly an odd one.

 

I'm kinda ruling out the flexplate, especially since it was smooth as butter before. It probably won't hurt to get a spare one, and test it. I don't want to take apart the trans unless I know what to look for.

 

Did you also install a "Beast" reaction shell?

 

It's a level 3 trans, that was done when it was initially built.

 

My last rebuild I installed one of those and the trans has had a weird vibration since.(it's been many years though). It's a early one and could be one with the imbalance problem. I need to remove it.

 

Ok, gotcha. Well since the vibration wasn't there before replacing the clutches, I doubt that's it. I'll probably start with pulling it, and re-clocking the converter on the input shaft. Something tells me that's where my problem is. I doubt it's internal.

 

indexing is always a good idea, but when yer changing parts out, that can change the way everything balances relative to other parts. you rotated and tested at one end, did you do the same at the other end? ds rotation and balance can be affected very easily, but in my experience, imbalance that cant be tuned out is usually bc of bent parts..... that output shaft in those 700's is a sensitive piece

 

Didn't you say you did that? Or am I missing something.
By the way, I've a level 4 version of this transmission and it's smooth as silk. All the best bits from Sonnax and GM. Best trans I've ever had (touch wood).

 

I re-clocked the converter on the flexplate, but not on the input shaft. That requires me to pull the trans, slide off the converter, rotate, re-seat it, and then mate it back up to the engine. That I have not done.

The vibration is also there when I'm sitting in park or neutral.....can't be the output shaft or driveshaft.

 

Thinking that might be what I was missing.
​​​​​​I suppose anything that was possibly changed is worth revisiting. Drag about having to pull the trans though. I went through three different transmissions trying to isolate the problem and stumbled across the reclocking procedure after the fact.
Good luck.

 

Thanks for you input man.