I'm trying to find out what type of fluid to put in my 2008 Sahara unlimited. I'm replacing the transfer fluid, differential front and back. Are there any synthetic oils I can sub for and do I really have to buy them from dealership.

 

Don't buy any fluids at the dealer. You can get them all at your local auto parts store. If you don't know what to buy, ask the counter clerk.

 

I use all synthetic Mobil 1 products in my rig.

 

What weight do u use for your differential gears and what kind of jk do u have?

 

The deal said it uses a special type of fluid with an additive for the differential gear so can I use aftermarket and what type?

 

IF you have a limited slip rear diff you will need friction modifier. Many synthetics come with that already in them, the bottle will say. I think they call for 75-90 weight gear oil. I used 80-90.. not a big deal with axles.

Transfer case just uses automatic trans fluid.

The only "special" fluid called for by Jeep is in the manual transmissions.

 

Great advice, thanks😃

 

75-90 synthetic and it requires no friction modifier. I have a 07 Jku on 37's with 5.38 gears.

80-90 Dino does require a modifier for the limited slip.

For how often you change tranny and gear oil I feel there is no reason to go cheap.

 

Do you need friction modifiers if you use Lucas 75-90

 

Will it it harm my differential if I added a thicker fluid like from 80-90 to 75- 140 I think that's it. I have 35's and a 4 inch lift. I go out off roading about twice a month. Sometimes I tow my two dirt bikes so if I changed would that make a difference or no.
Thanks.