Hi, I've had the truck in my garage parked for 2 days and notice a puddle of fluid underneath the rear drive shaft/rear end.

My rear universal joint is wet, could it be a seal?

also there seem to be some play, if I take off my driveshaft and grab the yoke on the rear end, should there be any play at all?

THANKS FOR ANY HELP IN ADVANCE!

SBishop

84 Ford F-150 4X4

 

Might be time to replace the u joint.......I'm thinking there shouldn't be any play....

 

usually that is the pinion seal leaking. and no there shouldnt be any play. the yoke should be tight.

 

I agree with the Pinion Seal Leaking. Replace the seal, and the leak should quit. You must get the bearing preload exactly right or problems can result however.

Where exactly is this play you are talking about? Is it in the yoke itself, where it bolts on, or is it inside the rear end itself? Where the pinion gear meets the ring gear? A small amount of play is acceptable inside the case, just as long as it isn't excessive. If in doubt take it to a reputable shop for an estimate. A reputable shop will tell you if the play is excessive or not.

BTW, excessive play in the rear end can cause the Pinion seal to leak.

 

I dropped the rear shaft and tighten the large nut on the yote. I was able to turn it almost a full turn, it was leaking from there. the seal is nice and dry. I will keep on eye on it to see if it's still leaking in a few days. this is not the first time i've had to tightent the nut. third or fourth time in the last 7 years or so.

thanks for all the suggestions.
SBishop

 

That nut you tightened is where the bearing preload must be set right.

There is a procedure for adjusting the bearing preload in the haynes manual using a torque wrench, but it's a pain.

I'd suggest having the truck taken to a shop, and have them adjust the preload for you, and/or inspection.

That nut should not come loose like that.

 

If the leak is not from the seal, the leak is from the splines of the half round companion flange and the pinion shaft.

Before you remove the pinion nut, you're suppose to jack the rear up, remove the rear wheels and brake drums.
With an inch pound torque wrench you measure how much torque it takes to move the pinion a couple of revolutions.

Then remove the pinion nut and flange. I use some Right Stuff by Permatex and put some on the splines of the flange and pinion shaft.

When you retighten the pinion nut, you tighten it to the same torque or a little more than what your first measurement was. (8 to 14 inch lbs. for used bearings).

The factory manual says not to reuse the old pinion nut.
I'm not sure why but maybe because it stretches or because of the sealer/coating that a new pinion nut has. A pinion nut cost around $2.00.

The final torque on the pinion nut when the installation was new was 160 ft/lbs.

As far as moving the flange/pinion shaft in or out, there should be no play. Moving the flange right or left (CCW or CW) you will have some back lash movement. Around .008 - .015 inches.