Transmission update for High RWHP Z's : Power Issue

[The Devils Z]

I posted this on tt.net. Figured I'd share for reference information purposes...if you want the history

read history here


With help .. I tore down the transmission today and looked into all the bearings ( pivot, throw out, countershaft, input ~ front , rear, and main, misc that I am not mentioning ) ....all the bearings seem fine ... I have about 20K on this tranny at 600rwhp plus.
Upon further inspection, it looks like 4rth gear is starting to show signs of small wear. The countershaft gear ( ?? ) that it interacts with has real small signs of wear. Based on the way it was explained to me the 4rth gear is always distributing an engine load even when not in 4rth gear.

Looking at the tranny parts visually, you can see that 4rth gear is always in motion, just not engaged until that gear is selected.

It seems that my 4rth gear can not support the power levels that I am at indefinitely. This would also explain my tranny failure 2 years ago when I was speed shifting a lot. This tranny "blewup" from a 3rd to 4rth shift ( no synchro issues also).

Below are some pics. You can't see the 4rth gears with enough detail to see what I am talking about.

My options at this point are

1) to probably take all the gears and bearings including a new 4rth gear and get it cryno treated to see if that will increase the longevity.

2) Throw it back together as is and cross my fingers

3) Buy another used tranny while I get this one cryo treated.

Decisions Decisions .. enuff talk ..a few pics ...


first a lovely pic of my SZ cracked split downpipes ..

I tried to repair these myself ( because they have cracked 2 times already) - so i can't return them



Flywheel side of tranny housing





Tranny housing assembled



Input shaft / Countershaft / Gears



Right side view



Left to Right

on the top: Input shaft
1rst gear / Synchro / 2nd gear / 3rd gear / Synchro / 4rth gear

on the bottom: Countershaft

Countershaft gears



Back half of the bell housing



Neutral / 5th gear / Reverse



Looking over all the gears and bearings