When I put new gear oil in my rear end do I need to add a additive to the oil? I am using vavoline(or however you spell it) 75/140 syn oil and i was just wondering if i put anything in with the oil.Also I went to get some tranny oil sun. And nobody knew what kind to get (Go Advance Auto) So if yall could tell me again what to ask for or what to look for it sure would help me out. Thanks

 

Mercon for the trans. No you dont put any additive in the rear end. Auto parts store should know what you need when you tell them what kind of car you have.

 

Forgot to mention. If its an automatic, you need mercon v

 

I heard something bout sycromesh or something like that. whats that. do i just say mercon tranny fluid. they tried to sell me some auto tranny fluid.

 

Syncromesh for what? Yes, mercon, it should tell you in your manual as well.

 

i heard syncromesh was a brand of tranny fluid. maybe i need to go to a different parts store.

 

Best bet if your unsure and want the right stuff is just buy it from the dealer and keep your sanity. (LOL)

 

about the additive in rear end i was reading a manual at the store. and it said add 4 oz for the trac lok i was just wondering maybe i read it wrong.

 

Not sure about that. The guy thats putting my gears in told me to supply the fluid with the gears and thats all I need. The only thing he suggested is the master bearing kit, but I dont need that unless I have 60000 miles. Other than that, gears and lube.

 

according to owners manual
the rear axle uses motocraft sae 75w-140 synthetic rear axle lubricant and 4 oz. of additive friction modifier xl-3.
the auto trans uses motocraft mercon v only.
the manual trans uses motocraft mercon atf only.
the syncromesh is a special manual tranny oil made by GM for the tremec, this is highly recomended for racing use.
I hope this helps