Torco RGO Racing Gear Oil (85W-140)

I installed 4.10's in my Mustang GT and had some noise due to how they cut the gears now. Changed the fluids many times, rechecked wear patter's...bla...bla it was all SAT but had constant gear noise 40 MPH+ Long story short looked around and decided to use this stuff with 2-4oz bottles of Ford Friction modifier fixed my problems! It's so much more quiet now, it feels smoother and the differential is actually a little cooler when I check it after driving. Get this stuff after you do a rebuild and break in your gears and it's time to changed the oil and you are going to be very happy! Yes, a little more expensive then most brands (other than Amsoil which is close to this GL-6 stuff) you pay a premium penny but you won't ever have to worry about it again. Hands down worth it!

Best Fluid For 2006 GTO Differential

2005 GTO I recently purchased with 108k miles had a TON of clunking noise and grinding in the rear. I bought 2 bottles of Torco 85-140 (holds 1.6) and stopped by a local FORD dealership to buy a 4oz bottle of their friction modifier($8). Mixed the entire 4oz of modifier into the 1st bottle of Torco, drained the rear end gear oil (simple) and added that bottle with the modifier and another 2/3 of the 2nd bottle. Unbelievable how INSTANTLY this stopped ever noise in the rear end I've had since I bought the car. This stuff is a dream come true & I'll never put another fluid in my GTO's rear gear.

The best gear oil for the GTO rear but make sure to get posi additive too.

Torco gear oil, non synthetic. I changed the rear gears and this was the reommended break in and full time service lube.