# Is a gl5 gear oil that bad for an o2a transmission



## blubullet509 (Oct 15, 2007)

Ive been getting some increased transmission noise, I dont think its a gear oil related problem, but im no expert. Ive been running a synthetic 75w90 in my o2a trans for about 10k miles. In the last 2k it has had alot more noise and seems to slowly be increasing. I honestly think its the differential, as it has a slight whine in all gears. But... the last 2k miles have been the hardest miles this transmission has seen guaranteed. The engine was rebuilt and track driven all summer so its not that crazy for me to beleive its just seen better days since it has almost 150k on it. Im going to rebuild the trans or a different one this winter with a new differential an r/p gears but just trying to find out if a gl4 is the way to go or if a gl5 is really that bad.


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## AudiSportA4 (Mar 3, 2002)

The only problem w/GL-5 is the incorrect coefficient of friction for syncro engagement. No harm unless you are jamming into gear. Drain and refill with a thick GL-4 75w-90 and hope for the best.


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