leaking rr pinion seal - urgent or not?

[lovetoski]

Hello all,

Did a few hours of PM on my wife's 80 yesterday. While greasing the rr u-joint, I noticed that the rear pinion seal is leaking. Diff oil is heavily splattered under the truck, directly above the pinion. Last time I greased the u-joints was 5,000 miles ago. I added about 1/2 cup of gear oil to bring the diff back up to full. With 225,000 miles on the clock I guess it's about time for this seal to pack it in.

I've read through the "pinion seal" posts in the archives, and am a little uncertain about doing the on-vehicle pinion seal repair. I can do it, but it sounds like it can be a hit or miss deal. I travel a lot, and my wife puts 25,000 miles per year on her 80, so I need to do a repair that is going to stick.

I talked to Randy's Ring and Pinion this am, and their recommendation (based on the total milage + plus the fact that we plan to keep this for another 225,000 miles) is to completely rebuild the diff (new pinion seal & bearing, new carrier bearings). I'm leaning this way, and would have them do it. (C-Dan, stay tuned for a call...)

Since it appears to be pretty simple to pull the rear diff (slide out the axles, unbolt the diff from the driveshaft and axle and go) I'm thinking of taking the diff out myself. This will save ~$125 in labor they say.

Due to my travel schedule of the next few weeks, I won't be able to do this until early Oct. I'll be home on the weekends, and can check to keep the diff topped off. Is it OK to keep running this way, or am I putting the family or my wallet in jeopardy?

Thanks as always for the advice.

Best Regards,

 

[nakman]

Well since no one else has responded, IMO replacing the seal is not urgent, as long as you keep the diff full of gear oil. And your plan to just top it off on weekends sounds like a good one. You could also run dyno 90wt, instead of synthetic (not sure what you're using) since the dyno won't leak out as easy. But fixing it for real in October is obviously the best plan. hth..

 

[cruiserdan]

I agree with Nak.

Do not let it bleed out and you can go quite a ways.

 

[lovetoski]

Thanks guys!

 

[loquito]

I replace both front and rear seals on mine, I agree it's not urgent, but for a seal under 15 dallors and an hour of time and mine no longer leak, time and distance will tell on mine.
Hunting down the inch torque meter took the longest time.
Good luck
S

 

[landtoy80]

I have rebuilt the front and replaced the front pinion seal (after the rebuild) due to a worn flange.
I only rebuilt the diff because of milage 200K+ mi. And I had the axles out replacing the birf's.
The bearings were good and didn't need replacing but did it anyways. I had a ring on the flange where the seal was. If you rebuild get a new flange.

Replacing the pinion seal is not too hard as long as you know what you are doing before you dive in to it.

I was going to rebuilt the rear as I have the rebuild kit and a friend that will help me. He helped me with the front diff. I ran out of time this year so it won't get rebuilt this year.
If you do it your self, find someone to help you that knows what they are doing as it is a big job to do it.

 

[montocr]

pinion seal

Beware of doing seal from outside. (without dissassembly and replacing crush sleeve). For every 0.001" of crush on the crush sleeve, the rolling resistance is increased by approximately 10 inch-ibs. The spec on used bearings is about 6-8 inch-ibs. There is no real accurate way to measure this, without full dissassembly. Besides, at 225k it could probably use bearings anyway.