Originally Posted by 06silvercrew

No matter how you cut it, 75w140 is expensive!!!!

Originally Posted by Krewat

Funny thing. My rear diff made a slight whine at highway cruise from brand-new. Never changed, never got any better, but was so slight it wasn't worth doing anything about.

Had to clean up the rear cover, changed out diff fluid to royal purple.

Noise got a LITTLE bit quieter, but didn't go away.

Had a leak, had to fix it, and tried Mobil 1 this time.

NO NOISE.

As for the LS additive, are you sure it has the additive, or it's billed as "not requiring it"?

Originally Posted by 06silvercrew

No matter how you cut it, 75w140 is expensive!!!! I have 60K on the clock and have a nice finned aluminum cover sitting in the garage, but damn near $70 for 4 qts of liquid gold LOL

Originally Posted by EXv10

That's because they don't make a lot of it.

Originally Posted by EXv10

There is 2 versions of Mobil 1; 75-140 synthetic. Regular and the LS version which has the additive. That is an interesting observation with the addition of the Mobil 1 ! Sometimes the ring and pinion don't mesh perfectly from the factory, I has seen this also.

Originally Posted by ameinig

Right. I know it has been discussed before, but the purpose of the LS additive is to make the LS NOT work. That is why it reduces chatter.