Diffferential Leak at Front, How to Refill
 

It looks like the front seal of the differential on my 1999 Econoline 150 is leaking. I was hoping it was the vent tube but no luck, it is clear.

Is there anything special about changing the seal?

How do I refill the differential? It doesn't seem to have a plug.

Thanks

Pete

Nothing special. Just try to get the torque on the pinion nut as it loosens so you know where to go back to. There should be a little plug above the seal on the drivers side. Use a 3/8 ratchet to remove it. Make sure the pinion nut is tight enough that it does not cause the pinion gear backlash to be too great.

The plug is located on the side of the differential housing. 3/8 drive ratchet usually works. Once you remove the front driveshaft at the front, the nut that holds the flange on the pinion shaft is removed and the flange will usually come off sometimes with a little help. Then you can get to the seal. Sometimes you can punch a hole in the seal , insert a sheet metal or drywall screw and pry the seal out. Good practice is to replace the nut with a new one and make sure to apply some silicone sealer on the seal outer surface before carefully driving it in ,squarely, to the same distance the old seal was installed. If you have any clean grease available pack the inner groves of the seal with the clean grease and it will keep the inner garter spring on the seal,if it uses one, from flying off as you drive the new seal in. Assemble in reverse order. Not too dificult to do . hanky

Thanks guys. I have the shop manual (on CD) and it shows a special tool for pressing in the flange. (It also shows one for the seal but I don't think that is too necessary if I take it easy).

The flange tool seems, from the picture, to "extend" the threaded end of the shaft out more. Almost like you can't start the nut on with the flange not seated yet. Is that a problem or are they jsut trying to sell a tool?

Thanks Again,

Pete

You do not need the "special tool". Just have the loosening torque so you can install the nut to the correct torque. The nut will probably torque at a little more than 250 lb ft.

Crap! My torque wrench only goes to 100 ft lb. Maybe the parts place will loan me a "bigger" one.

Thanks for the heads up.

If you have a 1/2 inch long handled ratchet, or a 1/2 inch breaker bar, and pull until you can't pull anymore, you will be close. You need someway to block the rear end so the nut can be tightened. We use a metal bar with a rectangle hole cut in it to fit the flange fairly tight.

Well, that sounds easy enough. The old "calibrated muscle" I guess. But my 63 year old muscle or my weight lifting 27 year old son's? Just kidding.

I gather, "tight as you can get it" is about right.

Thanks

Pete

Now that you have the job finished and want to add gearlube to the differential, does your 150 have a limited slip differential? If it does, don't forget to use the correct lube for it. Depending on how much you lost will determine how much friction modifier you might need to add.
Have a good one! ,,,,,,,hanky

Hey petec. I would venture a gusee as to you pulling as much as your son. Somethings youth and muscle can not overcome.