My truck has 130,000 miles on it now, and has been through some rough wheeling, and lots of 4wd use during the winter. I think its about time to change the front and rear diff fluid, along with the Tcase fluid.
I have done a lot of searching and reading on how to do this... I found a nice how to on the changing the tcase fluid, so Im all set with that.
Now, from what I understand the front diff has a drain plug, and the rear does not. The front, I will be able to simply open the drain plug and the fluid will drain out, and i can screw the plug back in, and fill up fluid into the fill hole until it starts poring out, close it up and be all done.... Right?
The rear...I have to take off the cover in order to let the fluid drain... Right?
So after the fluids drained from the rear, I simply scrape the gasket (rubber? paper? liquid seal?) off of the diff and off of the cover. Then I purchase a new gasket from autozone and replace it and bolt back up the cover and fill with fluid from the top fill hole? ...Right?
Or is it different.... when I take off the cover is it a gasket that I replace? Or is there a "mote" (thinking of the trench around a castle" on the cover that will be filled with gasket sealer stuff, that I have to get out and refill.
Do I use locktight? What kind?
And Im assuming that all of the fluid types and capacities will be in my owners manual right? (not service manual)

Thanks for anyone who had the time to read and respond...I just want to make sure I do it right and dont have any problems its my dd and I have no spare vehicles, or money to pay a shop.

 

Front does not have a drain either. You are going to have to get a hand pump to suck out what you can and fill it back up. You can do the same for the rear but taking the cover off is easy. All you need it black RTV to seal it back.

 

damn I thought I read that front had a drain... oh well. Does the front diff cover come off easy like the rear? are all of the screws holding it on accessible? And while there open I read that some people spray it down with brake parts cleaner.... is this wise?
So aside from the fluids...all I need from autozone is black RTV sealant? no locktite?
Also, It seams that most people prefer fully synthetic fluids. So get fully synthetic for front, rear, and tcase?

 

You can't take the front cover off without taking the diff out.

I have seen people spray parts cleaner too but mostly to get rid of the oil completely so they can inspect for damage.

I run synthetic in everything. Its really up to you though. All the quantities and viscosities are in the manual. Do you have a l/s in the rear? If so you need friction modifier if you use plain gear oil but most synthetics have it mixed in. Just make sure you read it.

 

Oh damn, I wasn't aware I had to take the whole diff off. Thats gotta be a pita... is it worth it to take it to a dealer?

 

They will probably charge you close to $90 to do it. Its not too hard to do you just have to buy or borrow a hand pump.I used something similar to this: - Harbor Freight Tools. You can also use it to fill the diffs just hold the discharge hose on the pump because it tends to slip out when you are pumping.

 

Alright cool Ill just pick one of those up

 

GREY RTV!!!!!! black will leak as its oil based. Ford uses GREY rtv from the factory for a reason.

 

You sure? I used black with no problems. As a matter of fact the tube I bought had a better resistance to oil than the others. Red did leak on me.

Edit: Found the stuff I bought: Permatex® Ultra Black® Maximum Oil Resistance RTV Silicone Gasket Maker

 

or you could get a 3 dollar gasket slap it on and be done

 

You dont need a gasket, now a 3dollar gasket is gunna leak in no time, RTV done right wont leak at all.

Make sure you torque the cover, or they also leak. damn fords.

 

The rear will take 2 1/2 32 fl oz bottles (the bottles the gear oil comes in) of 80-90 IIRC. The front also takes 80-90 but I don't remember how much fluid. The t-case takes Mercon V trans fluid.