Hey Guys..wondering if somebody can help...was on the highway this weekend when i pulled over for some coffee i smelled like burnt trans fluid, when I checked it was a leak from my rear differential..where the driveshaft connects. Called a mechanic up and said the pinion seal needed to be replaced but said that the crush sleeve needed to be replaced as well to do it "right". Is the replacement of that part absolutely necessary, or is replacing the seal enough..He said that it was necessary to replace the crush sleeve and it would run a lot more because the diff needed to be taken apart but I'm thinking this is a simple seal/gasket replacement..What do you guys think?? Thanks for your help!!

 

The correct procedure is to replace the crush sleeve, although I am questioning the necessary extra work involved. Drop the drive shaft, remove the yoke, pry out seal, front bearing will fall out allowing the sleeve to be removed. The trick will be crushing the sleeve so as to not over load the bearings. If it was me, replace the seal only and torque the yoke nut only enough to remove excessive play on bearings.

 

I think Bill's advice is sound.....I'd put at least 100 lb/ft of torque on the nut. Once everything is fixed up get the ride out on the highway and run it up to about 80mph and listen for any whine or howl from the rear axle. If the thing is quiet, you're home free. If not, then the "right" way to make the repair to get the correct pinion shaft bearing preload is in the cards.

The "right" way does not require disassembling the differential, but removing the wheels and brake drums is required to get accurate running torque values at the pinion shaft.

 

Thanks guys!! I appreciate your help and advice.....Thanks to guys like you, we all get to enjoy our Fords more and get to know them the way we should!!

 

I would replace the seal and look reclose at the diff flange for grooves and excessive wear if its worn. Replace it.. retorque the flange you also want to index or mark your driveshaft to the flange to emliminate the possibility of vibrations...
top of the diff your on your way.

a worn flange will prematurely wear out the new seal..

 

Actually Guys.....one more question, how can I find out if my diffy is a LS, limited slip diff...this truck is a 2006 F150 FX4 and was told it uses oil w/ an additive if it's a LS but not sure if it is or not......I was thinking about using reg synthetic.

 

If you dont replace to crush sleeve, be sure to mark the threads showing on the shaft. The crush sleeve is a B@@ch to torque. If you dont torque it right, you could tear up your gears in a hurry. Ive seen it happen. You probably have a limited slip, but to know for sure, look at the tag on your rear cover, that will tell you. If it is limited slip, it will say LS, and you will need to add the friction modifier. Be sure to add 75w 140 synthetic.

 

Ford puts a L between the first and final number of the gear ratio where the decimal should be.