RP Maxgear 75-140 OK for Vette diff. ?

[drfeelgood]

I own a 2005 Corvette, and already changed the diff fluid to M1 75-90 with limited slip additive to try to decrease the chatter in tight turns. (A relatively common issue in early C6 models). Still has some chatter. At least one hi-perf diff company recommended using RL 75-140 in their diffs. My car gets driven fairly hard and will see some track time at Road Atlanta. Would RP 75-140 be a good choice to try?

 

[reyjay1]

Either that or the 75w90 which i would be more inclined to. Generally no need for the FM LS additive with the Maxgear. The 75w90 will actually run a tad cooler and should be 1 or 2 HP delivered above the 140 weight.

 

[unDummy]

Did you use M1 75w90 AND a separate LSD additive? which additive?

I find that M1 gear oil usually needs aftermarket LSD additives in tight(new/rebuilt/low mileage) diffs. Tired diffs work well with M1 alone.
I know that Mobil1(along with Pennzoil synthetic GL5) claim to be LSD happy fluids. But, my experience is that you should add the additive in ounce increments until you've eliminated the chatter.

Visit your local dealer or autoparts store for another bottle of LSD additive.

 

[dailydriver]

What type of diff is in those Getrag center sections? Is it a steel plate clutch pack??

 

[drfeelgood]

I'm not sure about the exact type of LSD in the 2005 Corvette.
Yes, I did use the M1 75-90 and added some limited slip additive from Advanced Auto.
So, should I use 75-90 RP, or try the 75-140?

 

[JohnBrowning]

The RP 75W90 or 75W140 will work just fine in your diff. When I lived in Georgia I ran 140W gear lube in my transmission,transfer case and diff's and never had a problem. I do not like RP Max Gear in manual transmission becasue her in Michigan the RP Max Gear tends to lose it's cold temp shift properties after 10,000 miles of use. RP has the best Timken Load rateing of any gear lube I am aware of on the market.