Rear Diff fluid - Page 2 - Audi Forum - Audi Forums for the A4, S4, TT, A3, A6 and more!

Jan 2, 2011 | 10:43 PM

#11

jordon

Audi Forum - Posts like an A5

iTrader: (1)

Joined: Oct 2010

Posts: 366

From: saskatoon, canada

Re: Rear Diff fluid

Quote:

Originally Posted by mksu19

Although GL-4 is acceptable, A4 differentials will perform best with GL-5. The GL-4 additives simply do not hold up to extreme pressures as well. Remember that the differential is effectively multiplying the motor’s torque another four times. At redline in 1st gear, the differential is putting over 4,000lb-ft of thrust to the pavement. You want the maximum protection and engagement here.

I knew I had read this exact same thing word for word once before! Finally found it lol

FAQ: Rear Differential Fluid Basics

about 1/4 of the way down on the first post lol

Jan 3, 2011 | 10:57 AM

#12

Corrado_Guy

Audi Forum - Posts like an A4

Joined: Nov 2007

Posts: 117

From: South of Heaven

Re: Rear Diff fluid

GL-4 and GL-5 are not interchangeable though, they have different standards and can cause problems down the road which is why I never use the wrong product. The factory manual ELSA claims that both the differential and transmission (manual) use 75W/90 synthetic oil part number 'G 052 145 S2' which may have been superseded with a service bulletin but that I don't know. If you want to try different brands that is great but you should make sure the specifications of the product you use match the factories or just use factory fluids.