Hey guys any of you ever ran none syn. 85w90 in a auburn style rearend? I just did a fresh rebuild on mine and put RP 75w90 syn. w/additive and it was whining(i guess it was 2 thin). So pulled the rearend again and rechecked everything, it was perfect. So this time i put straight 85w90 and it is quite as a mouse. I went back and added the additive cause the clutches were chattering when turning, but now it is perfect. Is there any long term affects of this?
BTW the paper work that came with the gears said to use 85w90.

 

should be ok

 

alright thanks. so far so good