Transmission update for High RWHP Z's : Power Issue - TriStateTuners.com :: Home of Tristate Auto Enthusiast

The Devils Z · 12-31-2006, 09:44 AM

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

Honest_Bob · 12-31-2006, 11:54 AM

Wow, your a madman for tearing that beast apart.

Erik · 01-01-2007, 11:37 PM

looks liek fun man...
goodluck with your work.

peteyturbo · 01-06-2007, 02:04 PM

They look fine from what I can see, I would leave it be..

12-31-2006, 09:44 AM	#1
The Devils Z Tri-State Aficionado Join Date: Nov 2006 Location: Delaware Member #2908 My Ride: Nissan 300ZX Twin Turbo iTrader: (0)	Transmission update for High RWHP Z's : Power Issue 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

12-31-2006, 11:54 AM	#2
Honest_Bob TST Ruined My Life! Join Date: Dec 2005 Location: Easton, PA Member #1179 My Ride: 05 WRX Wagon iTrader: (2)	Wow, your a madman for tearing that beast apart. __________________ To view links or images in signatures your post count must be 10 or greater. You currently have 0 signatures.

01-01-2007, 11:37 PM	#3
Erik Tri-State Post Whore Join Date: May 2006 Location: Glenside, PA Member #1962 My Ride: 2001 Audi A6 2.7 Twin Turbo iTrader: (4)	looks liek fun man... goodluck with your work. __________________ --Eric '96 Mazda Miata \| FM V-Maxx Coilovers \| Jackson Racing Exhaust/Intake GONE To view links or images in signatures your post count must be 10 or greater. You currently have 0 signatures. 01' Audi A6 2.7 Twin Turbo \| Daily \| NoMods

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01-06-2007, 02:04 PM	#4
peteyturbo Tri-State Post Whore Join Date: Feb 2006 Location: NE Phila. Member #1450 iTrader: (0)	They look fine from what I can see, I would leave it be..