A couple weeks ago I helped a local GP buddy put a transmission into his car. He got it a while ago as a built trans. There was an odd wobble in the driveline once we got it in and on his way to work the second day something banged and there was no more movement in any direction. He asked me to pull it and go through the trans to fix it. Tonight it jumped out in about two hours and I started to tear into it. Dagger and I checked everything possible before pulling the trans. It showed input at the ISS and the diff was in good condition.

Out it came.... in a couple hours tonight. Then I tore into to for diagnosis.


The pan, clutch material and sparkling metal pieces.


This would be the view when you pull the cover off the side of a tranmission. The channel plate is the broken item we see.



Pulled the pump, valve body, channel plate. Found a 15/16" chain a bit out of it'* normal position. Took out the fourth assembly and gouged up the trans casing.



Unsure which chain this was, made in Canada.


A lot of work later it came loose, there is more damage to the fourth assembly if we look down into the leg of the trans.





Carnage out of the case
Fourth assembly

Fourth clutches were reasonably worn, lube dam got stuck on the clip of the output shaft, various other broken pieces



Diagnosis: 15/16" chain failure. Most likely from the previous owner as Daggers car is completely stock with a Wizzair intake and recently added headers.

Mike is looking for a new transmission unfortunately. The case at the bottom of the fourth assembly (leg of trans) is partially cracked and out of shape.

That tranny had seen some better days. I suppose the failure could have been much worse, but with the case cracked it just doesn't matter.

Hay Bill, you remember what I said on the phone when we talked about this?

Nope... hahahaha made sense didn't it.

This is the exact reason why I decided not to use my old 4T60E from the L27 in my L67 swap. Never seen that kind of damage before. Wow...

This is a 4T65HD trans. That had a 15/16" chain, upgraded input shaft, hardened 4th hub shaft and probably a few other goodies.

I have heard from a couple of specialized trans guys that the 15/16" is supposedly weaker than the 7/8" chain. Not sure about that as this is the first snapped chain I have pulled out. Looks like it broke right at the master link though.

Don't know how they compare in regard to chain strength between the two, but, I have heard numerous reports of people who swapped an L67 in their 1st gen w-body equipped with a 4T60E, modded said L67, and stretched the chain within just a hundred miles or so. Just something I wasn't willing to risk given other peoples' experiences.

I have NEVER seen that kind of damage in a 4T60E/4T65E trans!

Ouch... I can imagine that doesn't shift so well anymore lol

That'* surprising to hear Steve.