What fluid do i use for front and rear diff

[Alaskanredneck]

OK SO IM DUMB AND I CAN NOT FOR THE LIFE OF ME FIND THE THREAD THAT SAYS WHAT WEIGHT FLUID I PUT IN THE FRONT AND REAR DIFF AS WELL AS THE TC. I HAVE FOUND THE CAPACITIES ALL OVER THE PLACE BUT WHAT KIND OF FLUID. IM LEAVING FOR THE STORE IN ABOUT 1 1/2 HOURS SO PLES HELP THIS STUPID GUY.
BTW I HAVE A 91 EXPLORER EDDIE BAUER

 

[corkey]

i am pretty sure the front and rear diff use gear oil, probably 80/90 , but the transfer case would use auto trans fluid,

and use synthetic to get the most of mileage from your Ex,

 

[Alaskanredneck]

Would 75w90 work im having a hard time finding synthetic 80w90

 

[gavin]

yup, that would work too.
I know Napa and Schmucks sell Royal Purple synthetic 75w90

that's what I used.

 

[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?
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?
WOULD IT HURT TO PUT MODIFIER IN THE FRONT?

 

[snoborder42]

The front diff is an open differential, therefore it doesn't need the friction modifier. Only the Ford Limited Slip diffs require it. The transfer case doesn't need it either. Also the transfer case uses regular ATF, not a gear lube.

As for the rear diff, just pour in the entire bottle along with the correct gear lube and you are good to go.

 

[Alaskanredneck]

Damn then i have an extra bottle of friction modifier anyone know if it would help or hurt putting it in the front diff

 

[gavin]

it won't hurt, no. But won't do any good, either.
it's only necessary to help the limited slip clutch packs grab

also, what gear lube did you get? if you got a full synthetic lube, then it may not require additional friction modifier. I know the Royal Purple stuff does not require it

 

[HahnsB2]

It's not needed and last time I checked, FM makes the clutches less grabby... That's why you don't add it unless the clutches chatter (usually only fresh clutches will chatter).

 

[gavin]

FM makes the clutches less grabby...

d'oh
yeah... for some reason I was thinking the other way around. oops!

 

[Alaskanredneck]

I got the royal purple 75w90 I'm gonna put the FM in anyway. I just changed the t case fluid and it was pretty nasty, does anyone know what the hell that heavy weight bolted on the back of the t-case is.

 

[Maniak]

Its a vibration dampner... We don't use it on our X anymore since we just about ripped it off wheeling one time.. I haven't noticed any new vibrations.

~Mark

 

[X~FACTOR]

Vibration dampner? What the hell is that? That is not the 5th shock is it?

 

[Maniak]

Its a round weight thing that is bolted to the back of the transfer case. There is another one on the rear end on many explorers.

some also have a 5th shock (horizontal shock) to help with vibrations, but thats not on the transfer case.

~Mark