Can you use Royal Purple Synchromax in our tranny's???

I have 4 quarts Synchromax and 2 quarts Max-Gear....


If so I was gonna use the Max-Gear in the Diff and Synchromax in the Tranny

 

DO NOT put Synchromax in your transmission. That is for manual transmissions that use automatic transmission fluid or regular motor oil. From the website:

Synchromax is recommended for manual transmissions that specify an automatic transmission fluid or motor oil.

Use the MAX GEAR in the transmission. BTW, I just put RP in my trans and diff and unfortunately, I haven't noticed any great improvement in shift smoothness as others have reported.

 

yea I looked at there web site and it said Max gear for GL-4 and GL-5...lol so confusing GL-5 is supposed to be more corrosive right? and I read a post on this site that said someone loved Syncromax in there Tranny...lol

 

Is there any preferance between the RP Max gear 85w140 and the 75w90? Would you benefit from either in any location?

 

If you look at the RP FAQ, it explains that their MAX GEAR product does not have the additives that make regular GL-5 oils corrosive:

My vehicle's transmission specifies an API GL-4 gear oil. Can I use Max-Gear®?

Yes. Max-Gear® possesses both API GL-5 and GL-4 certification. Max-Gear® is formulated with Royal Purple's proprietary, Synslide® additive technology to provide the exceptional film strength necessary for GL-5 applications, yet it is noncorrosive to soft metals found in manual transmissions that specify a GL-4 rated lubricant.

Use the 75W90.