jrwilliams95z28

Hi guys, I need some advice. On sunday I changed my differential fluid (first time its been done since new [1995 camaro z28], I used royal purple max gear 75w-90 after suggested that from a friend.

now I am hearing a grinding noise from the rear when I turn the car [either direction around corners]. Now I cannot confirm for sure that no fluid leaked out but the car has been sitting in the same place for almost the whole time since the change and there is zero fluid on the ground under the diff or anywhere around it. I do however remember that I cleaned the entire diff with brake *cleaner* after to clean it up so I could notice if anything leaked and it does look a little wet at the bottom now. But still no fluid anywhere else.

I plan to take it to my mechanic tomorrow to look over it but does anyone have any idea as to whether or not royal purple works well with a 10 bolt LSD diff rear end? It said on the bottle it has the proper LSD additive so I did not add any more.

I scrapped the old gasket off clean on the rear end and the cover, cleaned the surface perfectly, used high temperature liquid gasket on both sides of the new 10 bolt fel pro gasket I purchased and torqued all the bolts down in proper side to side fashion to ensure the gasket compressed properly.

Did I do something wrong or is royal purple a bad choice for our rear ends?

jrwilliams95z28

Ok thanks ill try that! I changed it at my parents place and drove about 30kms (20ish miles) from there to my place and it was alot more quiet, felt better to. Noise only started the last like 1km of the drive I was just on.

speed_demon24

iTrader: (6)

Auburn says not to use synthetic in their differentials, but its probably shot anyway if this is the first time the fluid has been changed.

jrwilliams95z28

really? no synthetic? I've read a lot of people use royal purple successfully. the car only has
40,000 miles original miles on it so its not excessive for the first change but I am not 100% on whether or not the original owner changed it just dident look or smell good.

jrwilliams95z28

the ring gear and LSD both looked really good though.

jrwilliams95z28

and I filled the read up to the fill hole, it took 1 and 3/4 of two bottles of the royal purple max gear

devildog214

i just used good ol' gm/delco gear oil my car sat for 5 years so all the fluids were changed, it quieted down my rear end whine somewhat, no grinds like you were getting.

jrwilliams95z28

I think im just going to get my mechanic to swap the fluid to regular gm fluid with gm additive tomorrow. not worth the headache to run synthetic in the rear i guess especially if auburn (who I just heard about) is saying not to lol

speed_demon24

iTrader: (6)

Buy the ford additive instead. Its $6 vs $25 from gm.

jrwilliams95z28

UPDATE: Ok I decided to try just putting some GM additive along with the royal purple already in there and (since it was raining all week) I just got to take her out and test it and there is no noise what so ever from the rear now. its quieter than ever!

So to just to give people a heads up, don't trust Royal purple's LSD additive use the GM LSD additive along with the royal purple if you use it!

SS RRR

iTrader: (2)

Actually this should be a great testimony to NOT use any Royal Purple product. Just use a quality gear oil and additive.