I noticed today while under my truck changing the Fuel Filter that the Rear Differential had fluid slung all over the place. Right where the drive shaft enters the differential. Is this a bad seal and is it a big job to fix? Any comments would be appreciated.

 

Sounds like pinion seal not sure how hard to fix , if its leaking bad keep an eye on diff fluid.

 

It's not a terrible job, but requires some specific tools to do it.

You'll need a 12-point 12MM socket, preferably a swivel one. I can't recall the size of the pinion bolt, maybe 1-7/8? Then it's get the yoke off, and old seal. Check the yoke for any excessive wear at the spot the seal sits. If it has a big groove you will need a new yoke, or a repair sleeve. The put it back together, and refill.

Takes me ten minutes on a lift. But I do it all the time...

 

Isn't there a crush sleeve involved in the pinion assembly? If overtightened you will change the gear mesh pattern....don't overtighten or undertighten.

 

Use a new nut,and when you contact the crush sleeve give it about an eighth to quarter turn more.it'll be fine.

 

Perfect...just wanted to make sure the OP didn't ruin his rear end in an attempt to fix the leak...thanks steelhead

 

Thanks guys... I did the job today and had to use a flywheel puller to get the flange off after dropping the drive shaft and removing the main nut. They told me at the parts store that all I needed to do was lightly tap on it with a hammer to get the flange off... not true... this sucker was stuck on there!!! It went back on equally as hard. So much so that I had to turn the nut to help push the flange back on.
Problem... I could not tell when to stop tightening the nut as it was driving the flange back in place and giving much resistance the entire way... How do I know if I over tightened it? I ran the truck on the highway for about 20 miles and the differential was pretty hot to the touch...I don't know if that is normal or not. Fluids were filled properly prior to the run.

 

Well, this is the tricky part. But the big thing is that you have no in and out play with the yoke. Some very minimal up and down (which is gear mesh) play is correct. That's the best way to describe it over the internet that I can think of.

I rarely can just tap them off. I usually end up using my air hammer to remove the yoke...