its a 92f150 ford truck how hard is it. how is it done and what oil is used it has an 8.8.does it have to be cleaned?

 

if you mean the rear axel, you need to take the cover off the differential to drain it down, get some sealant and put the diff cover back on, then fill it back up with 80W-90W diff lube (If you have the 8.8 rear end like I do)

 

You have the grind the surface of the cover and the axle where it mates to get a good seal.

 

You don't need to grind it. I just use a putty knife and my fingers to peel away any remaining RTV after removing the cover. Some solvent might also help break loose the real stubborn stuff.

Unbolt the bottom bolts on the diff cover and left it leak out the bottom into a pan. Once it stops unbolt the cover completely, check the ring & pinion for any wearing/chipping to make sure she's in good shape, have a quick look at the spider gears in the carrier. Dip your finger into the bottom of the pumpkin (yes there sludge down there) to make sure that there are any huge metal shavings, you will probably have some small metal shavings so don't worry about that. Clean out the sludge with some rags and solvent as best you can, and throw some RTV back on the diff housing where the cover goes on. You want to apply a constant bead all the way around the mating surface AND apply RTV in a FULL circle around every bolt hole to make sure you get a good seal.

This guy did a sloppy job but you get the idea.


Throw the cover back on and screw the bolts down until you start to see the RTV squish out from the sides of the cover. Let the RTV dry into a seal (check tube for proper curing time) and then torque bolts down to spec. The filler hole is on the forward side of the diff, use a 3/8" socket wrench and put the drive directly in the hole. Refill! Good luck!

 

it doesnt need a gasket or does it matter. RTV doesnt cause any problems with the axle

 

You don't need to use a gasket, the RTV dries into a rubbery solid and makes its own gasket. As long as you allow the RTV to dry before adding fluid and driving the truck then you will have no problems.

 

There's a gasket available for it, but you can either use straight RTV or use it along with the cork gasket. I've done it both ways with no problems.

 

i like using the gasket and i never have leaks.

 

remember if you have a trac-lok rear axle(both tires spin) then you need to add a bottle of friction modifyer, only sold by ford, to the 80w-90 fluid