C5 Fluid Changes to ????

[chris308]

Getting ready to lower my car soon, and i figured while it was up on stands to change out the fluids in the diff and MN6...

What do the shop owners here recommend also the DIYer's??

Cars a 99, tranny has the paper blockers i assume.

 

[chris308]

no one here changes their own fluids?

ttt

 

[fletcher4u]

I use GM diff lube and 2 GM additive trans gets 5w30 Mobil 1

 

[RevXtreme 1]

Hi Chris,

I use either M1 or another premium full syn diff lube in the rear (they do not require friction modifiers usually) and for the MN6/MN12 I prefer a NON detergent straight 20w motor oil with 1/2 qt of Lucas oil treatment. I find smoother shifts, excellent wear protection, and the lucas seals & prevents leaks. Or there is a new ($10-11 qt) full syn fluid just released for trannies requiring Dex ATF that I hear is great, but have not tried it.:thumbsup:

 

[Mongoose]

I would use GM LS gear oil Part #88862624. That is the only fluid for the dif. No modifier needed. As for the trans GM manual trans fluid #88861800. That is all I install here at the shop on factory parts. With the trans you may opt to use something else. But I do not recommend anything else on the dif. to much risk.

Good Luck
Brian

 

[Rich Z]

I had Royal Purple put in both the trans and diff a while back. Shifting seemed much nicer to me, but it could just be the "washed car drives faster" syndrome.

I have no idea what Chris has in mind to put in the new tranny and diff..... :shrug01:

 

[Rich Z]

I have no idea what Chris has in mind to put in the new tranny and diff..... :shrug01:

Well I just found out today that Chris recommends Amsoil. He said he did some testing in a racing environment and Amsoil kept the temps in the tranny down about 20 degrees cooler than the other products he tested. Not sure what other products he tried, but that probably means substantially less friction.