[200q20v] Trans and Diff oils

Tom and Carlyn Jervis jervidae at cybermesa.com
Thu Nov 16 05:56:18 EST 2000

This is not something to be done casually.  First of all, those plugs 
are very tight, and unless the wrench has the right tools, problems 
can occur.  You really need a 17 mm allen to put on a hefty breaker 

Second, and VERY important.  GL-4 and GL-5 (and GL-6) oils are very 
different.  Do not let anyone tell you otherwise.

Differences have to do with corrosion protection of copper (bronze 
synchronizers), anti-foaming, thermal and oxididation stability, and 
the relative important of high-torque, low speed, or high speed shock 
loading.  The tests are technical in nature and not easily described 
(and I don't understand them).  Part of the difference has to do with 
hypoid gears that have a very high torque loading.

It is true that GL-5 has more as well as different requirements than 
GL-4, but the numbers do not indicate anything other than the set of 
tests.  GL-6, for example, has no requirements for high-torque 
applications, while 4 and 5 do.

I have used Redline for the last 60,000 miles with no problems.  You 
can buy direct from them (800 #) and they know the amount and 
appropriate type for trans and diff for the 200-20V.  Audi uses 
synthetics and if you live anywhere cold, you should too.

Two stories:

In the way and far-off times I had an Alfa-Romeo.  Tranny ran low on 
a long trip right after I bought it and I refilled with (naturally) 
transmission oil at a convenient garage.  Shortly thereafter I had to 
replace all the (steel) synchronizers.  Should have used straight 

Once, after deciding that my urquattro would be better with winter 
dino oil in the trans, I had to be pull started at 20 below.  After I 
let the clutch out, the truck pulled the car along a snow covered 
street for about 50 yards before the wheels started TURNING! 
Synthetics are excellent at low temps.

Lesson:  Read the directions.

Tom Jervis
Los Alamos, NM

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