transmission oil and rear differential?
 

do they use the same oil? im planning to change my manual transmission oil with redline mt-90 and im not sure if it will use same oil on the rear diff.? can redline be purchased at local autoparts store? and do you use 3 quarts for the transmission and 1 qt on rear?

RE: transmission oil and rear differential?
 

2.1 quarts for the tranny on the 5 speed, 2.7 quarts on the 6 speed, and 1.1 quarts for the rear diff.
I have MT-90 for the tranny, and redline 75W90 for the rear diff. I cant remember my thinking on why i got the two types, they're the same weight I believe.

RE: transmission oil and rear differential?
 

The MT90 is a GL-4 while the 75W-90 is a GL-5 with more EP additive and is recommended for hypoid gears.

RE: transmission oil and rear differential?
 

so was i correct in my choice of fluids?

Actually knowing that, wouldn't the 75W90 be a better choice in the transmission too, considering it shares fluid with the bevel box?

RE: transmission oil and rear differential?
 

It is best to follow Audi's recommendation (I don't own a TT (quite yet)) so I can't say for sure. A hypoid gear set is slightly different from a bevel or spiral bevel gear set due to the offset of the shafts.

In general, more additive than what is necessary is not a good thing as it may havenegative effects on other properties of the oil.

RE: transmission oil and rear differential?
 

Transmission - Gear oil: SAE 75 W 90 (synthetic oil) Part number: G 005 000 (same fluid for both 5 and 6 spd. only quantity changes)

Rear final drive - Gear oil SAE 75W-90 (synthetic oil)
Part number: G 052 145 A

Still gotta find the specs on those part numbers.