OK I have done a lot to this truck but this is a new one to me and I ma looking for advice. My diff is leaking BAD where the drive shaft connects. This is a truck I will have for life so I like to fix things right. What do you experts recomend I do? whole new rear end ( if so whats the best?), just new gears and seals? or just replace this seal? Thanks for any help. Here is a pic of my truck.

 

My guess is a bad pinion seal

 

so you would just replace that seal?

 

or is there a better rear end I can drop in?

 

It can be done. There differing views on doing it though. Ill tell you how I did mine. I got the new pinion seal, make a mark on the pinion nut that corresponds to the pinion shaft. Now remove the nut and the yoke. Then pry the seal out. Coat the flange of the new seal with a light coat of rtv and install it carefully making sure it seats straight. Now put the yoke on and the pinion nut, when torquing tighten the pinion nut to the corresponding marks you and then just a wee bit farther. I went about 1/8 of an inch past. Leak fixed and I have had no problems with the gear yet with about 2k miles.

 

Thanks for a great reply! I think I will do this. what about the diff rebuild kits I can find online for 150 bucks, Are they a good idea and are the hard to do? any special tool or anything?

 

Rebuilding a diff takes some know-how and a couple of special tools. You will need a dial indicator and an in/lb torque wrench. Not saying you can't do it yourself, but you'll probably want a good book on it (I'd recommend the one from Randy's Ring and Pinion.)

As far as replacing the pinion seal, there is a crush collar in there AFAIK...you want to be careful not to torque it too much when reassembling. Some will tell you to install a new one (requiring you to set up the backlash/preload/etc), but you can get away with the method mentioned above if you're careful. Good luck!

 

While you have the driveshaft out inspect your u-joints, also put a little lube on yoke before you slide it in, that keeps from scratching the new seal.

 

Thanks for the input. I think I will buy the 150$ kit. it looks like its just a few barrings and a cpl seals. should not be two hard.. I hope

 

Depending on your skill level I recommend rebuilding the rear. It's a lot like building an engine. Once done right it will last you for life and the knowledge you gain is valuable. Those rebuild kits have most of the parts you need. An inch pound torque wrench and a dial indicator and the biggest braker bar you can find. You can get all these cheap at harbor freight. Find a good write up online or in a book ( those things made of paper ) and its not real hard to do. If its a limited slip you may want to change out the clutch plates. If you want to do a gear change now is the time. Basically take some time and do it right and it should run for another 100k or more. BTW I highly recommend synthetic gear oil.