Fluid Change Questions

[snoborder42]

Well I've finally decided to change some fluids that I'm sure have needed changing for a while. I'm planning on changing both diffs and the transfer case. As of right now it has 130000 miles and all these fluids could very well be original.

Anyway, I am wanting to make sure that I get all the right fluids before I get started. And yes, I have searched for this but there is very little on the first gen x for these fluids.

1) The transer case I am pretty sure that it needs regular ATF Mercron III. Is this true even though I have a manual tranny?

2) The front diff. I have no idea what it needs, I found several different types.

3) The rear diff, I think it needs 75-140 but I'm not positive. And I know it needs the friction modifer too because of the gears I have.

 

[410Fortune]

1. Mercon III is fine.
2. 80W-90
3. 80W-90 with modifier if you have a limited slip


For the front diff you will either have to suck out all the fluid you can through the fill port or release the diff from the beam to drain.

In the back a good synthetic might be a good idea if you plan to go another 130K before your next change. I used to run Mobil Synth gear oil back there, but lately I seem to have my rear diff open yearly so I am now running Pep Boys 80W-90.
The 8.8 cover seals up well with silicoln and no gasket.

 

[Alaskanredneck]

Does the front diff need the friction modifer as well? I'm planing on changin the fluids and i bought 2 things of the motorcraft friction modifer, also does anyone know how much to put in or just pour the the whole bottle in?

 

[Alaskanredneck]

Btw forgot to mention i have a 91 x 4x4 automatic with i believe the dana 35 also do i need to put ant additives in the t-case when i change the fluid?