[V8] Hex size and MT-90/MTL

[qshipq at aol.com]

 Gentz:
GL-4 (MIL2105) is a really generic specification of manual transmission fluid.  Steve, the MT-90 covers both the 75w-90 and the 80w90 GL-4 specifications called for in a wide variety of 1980's and 1990's Audi manual transmissions.  It might be worthy to note some trivia here as well, that specific to your synchro anecdote, the v8 5spd and forward Audi manual transmissions used a revised synchro design (ala introduced on the 012/01A 80/90 chassis) that had the synchro braking surfface on the outer face of the operating sleeve instead of the inner cone of the gear.  This design change from the older 016 setup, increased the synchro surface area by some 33%, and this design has been used on every audi manual transmission since.  Add in a driveshaft mounted oil pump on the v8 5spd, I really doubt that using G50 vs Redline et al GL-4 synthetics, would make any difference in wear or mileage.  Maybe to your wallet?

Audi only dictates G0050 which are both GL-4 SAE 75W90 MIL2105 synthetic fluids.  The other guy meant to say he used oe GL4 in the transmission and GL5 specification in the rear diff, as that's what the factory calls for exactly.  

Those more nerdy at all this might realize that puts GL-4 in the center torsen and GL5 in the rear torsen.  And Zexel-Torsen claims this is absolutely fine, as the T-1 works well with either.  

As a rule, I'm not one to debate fluids, especially something as backwoods as gear oils.  I've gone thru a many gallons of Redline Gover the years in Audi Manual Transmissions without issue, and have also used the G50 as well, can't say one is better than the other...  The old MIL 2105 (GL4) and Mil 2105B specifications are about as plain-jane generic gear oil spec as you can get.  The biggest mistake in transmission fluids as I see it, is following the Audi "lifetime" fluid assurance.  

HTH and my .02

Scott J


 

-----Original Message-----
From: ron_01056 at yahoo.com
To: Steve Buchholz <urq at pacbell.net>
Cc: V8 at audifans.com
Sent: Tue, Aug 10, 2010 6:51 pm
Subject: Re: [V8] Hex size and MT-90/MTL


I'm going to agree I didn't have huge confidence in Redline when I did the fluid 

in my 5sp,

 and used oe Audi fluid in both the transmission and rear diff.

 I figured it worked for this many years.



 Ron

-----Original Message-----

From: "Steve Buchholz" urq at pacbell.net

Sender: v8-bounces at audifans.com

Date: Tue, 10 Aug 2010 16:31:01 

To: <allanvega at comcast.net>; <qshipq at aol.com>

Cc: <v8 at audifans.com>; <toml99 at todomundo.com>

Subject: Re: [V8] Hex size and MT-90/MTL



I must say that I've decided not to use Red Line MT-90 (or MTL) in my 

transmissions.  On my '88 5kCSQA I replaced the tranny lube at around 90k miles, 

and by 140k the 2nd gear synchros were gone.  No question that shifting feel was 

improved with the MT-90, but since the cars live in mild climes they don't need 

the thinner stuff ...



Fortunately I was able to get a NOS transmission to replace it ...



Steven Buchholz