Jeremi414

Am I correct to say I can put full synthetic in both differentials? I do not have LSD. I don't tow Im just going to use 75w90

jeepmojo

i dont use synthetic oil at all / valvoline has the additives required by chrysler spec.

im not saying synthetic is good or bad just that its not required . Check your owners manual . But i decided to just use regular gear oil as was always good enough . Just replace it every 25,000 or so if you expose it to water of any type to be sure your ok, and keep it well lubricated

Jeremi414

I'm sorry. It's not synthetic I picked up on sale but this

jeepmojo

good to go you could use a heavy gear oil in rear if you wish 85/140 but your still ok i believe with 75 /90 in both

i replaced with 85/140 in rear diff

Jeremi414

Thank you sir

jeepmojo

have fun dont forget >

Mark Doiron

That's what I use. BTW, just for the record: Synthetic is not safe for all differentials. I have an aftermarket Auburn Ected locker and the manufacturer specifically says to NOT use synthetic. Which is why I choose the Valvoline.

rob_engineer

Of course you are safe with synthetic in stock axles. In fact, Chrysler recommends synthetic if you are going to tow. Yes, I am aware that some aftermarket diffs specify not to use synthetic. I switched to synthetic at 4500 miles. Now have 57,000 trouble free miles. Even towed a 4000-5000 pound toy hauler around 5,000 of those miles.

goaterguy

I am a fan of synthetics but the TrueTrac doesn't recommend it. Stock diff are ok.