diff and trans case

Reply Subscribe

Thread Tools

Search this Thread

May 23, 2010 | 10:02 PM

99explr

Thread Starter

New User

Joined: May 2010

Posts: 9

Likes: 0

diff and trans case

Hi, i want to change the fluid in both diffs and transfer case. i would like to know how much fluid i need and what to put in them. do both diffs take the same thing? i have a 3.55 non-limited slip. also i read that i need to take the back diff apart and put it back together with RTV. Which one do you use? Black ,blue, copper? i will be puting in synthetic so any recommendations on brand ?

May 24, 2010 | 01:58 AM

4.0 Beast

Elder User

Joined: Oct 2003

Posts: 504

Likes: 0

From: Gilbert, AZ

I had both diffs done at the dealer and they used 75w140 with a bottle of friction modifier in each one. Not sure on the exact amounts but i think it was 3 quarts each. The rear diff is put together with RTV... any RTV would do. The dealer used black but if you bought it on your own im sure the color doesnt matter as long as its RTV. I would get the high temp one too. I would go with genuine ford oil as far as brands...... just my humble opinion

May 24, 2010 | 05:28 PM

steve(ill)

Hotshot

Joined: Jul 2005

Posts: 11,931

Likes: 180

your not taking the back differential apart, you taking the sheet metal pan off the back as there is no drain plug. you then glue the pan back on (and a dozen bolts) with RTV. The older trucks had 80-90 wt gear lube, non synthetic. THe newer spec is 75w-140... you can use either. You can use generic gear lube from Wal Mart if you want, dont make any difference at all.

May 27, 2010 | 01:36 PM

Graygeorge

Senior User

Joined: Dec 2007

Posts: 139

Likes: 0

My 98 exp Transfer case uses transmission fluid.

May 30, 2010 | 02:12 AM

99explr

Thread Starter

New User

Joined: May 2010

Posts: 9

Likes: 0

ok, changed out the fluid in the front and back diff and put in full synthetic 75w140 and changed transfer case fluid also. Went for an hour drive and checked everything when i got back. no leaks but the rear diff was so hot i couldnt keep my hand on it. The front diff was warm. is it normal for the rear diff to be so hot ?