Rear Pinion Seal Replacement

This site may earn a commission from merchant affiliate
links, including eBay, Amazon, Skimlinks, and others.

bluemax009

bluemax009

10 Year
Joined
Jun 1, 2013
Threads
22
Messages
127
Did an advanced search and found a few threads on replacing the rear pinion seal. Said it was simple. All that's needed is the seal, which I picked up today for $10 and a 32mm socket. I know there has to be a few catches...
Anyone got any tips before I get started
 
I just did the front seal today. Was easy enough. Some say you have to replace the copper crush washers. Others... Not so much. The longest part was the four bolts on the drive shaft.
 
You won't have anything open, really. I re-used my stake nut that way I knew how far to re-tighten. I think you'll be surprised how easy it is. Be ready with a catch pan once you pull the flange out. A seal removal tool would be useful.

On second thought, you could grease your driveshaft while you are under there.
 
I replaced a rear pinion last month and it was not as easy as I thought.

I swapped rear diffs and had to swap pinion flanges because of different year trucks. Getting the flange off one was a simple hit with the impact. The other would not budge. I ended up installing the diff I wanted into the axle that had the flange I wanted to toss. Slide the axle shafts in, put the bake drums back on and set my parking brake so the pinion wouldn't rotate. This let me use my breaker bar on the pinion nut and a floor jack to turn the socket. It actually worked and nothing broke.

I hope you don't have to do that!
 
I knew someone had to have a horror story. Always like to be sure of what "could" happen before doing discovery learning.
Thanks for sharing.
 
It seems like I preface every post I write with "I'm not the expert but...".

That said, I think once you release the pinion flange nut you have released the pressure on the crush sleeve that's between the two bearings on the pinion. Thus releasing the pinion preload. Now, the bearing has been seated on the pinion at some point (the last time it was rebuilt - or built) so that may be enough to hold preload on the crush sleeve, but the FSM says not to back off the nut if you go past pinion preload settings.

You can PROBABLY just put the new seal in, torque the pinion nut down a LITTLE at a time (get an in-lb torque wrench) so you apply pinion preload properly and go.

Just something to be aware of - maybe 100 will chime in and say they've replaced the seal a hundred times each and never replaced the crush sleeve. I'm just going off the rebuild procedures in the FSM and my recent experience putting in ARBs. Take a look at the last posts in my thread - sig line - and learn from my discovery learning.

Good luck,
TDC.-
 
If there is a solid spacer in there (hint, hint, get one if you ever have the diff opened up) then you can simply re-torque the pinion flange nut and you're good to go.

If you have a crush sleeve then technically it is a one time use part. I have read of guys being able to just R&R the seal and re-set the pinion bearing pre-load using great care with a crush sleeve. I'm pretty sure that I'd only do that as a "getcha home" trick, but others seem to be fine with it.
 
Nice write up Mr Machinist, well done:clap:. I have that same seal from Marlin on my bench and will be doing the change soon.
 
Ok. So far first part went well. Now that I'm down to what appears to be the seal over the gasket I'm stuck. Not quite sure where to apply leverage. There's a soft membrane on the around the inside of the seal. Don't want to damage that. Where should I pry or pull?

image-3627801076.webp
 
So after seeing the machinists post and pic of his seal I've decided that mine looks pretty pathetic too. Ordering the Marlin Crawler tonight.

image-3401070677.webp
 
All you need to do is wedge a big screwdriver in there and pry on it until it starts coming loose. I had some trouble getting it out, but eventually I got it. The seal in there now will be destroyed, but there isn't anything else in there to hurt really.
 
just destroy the old one and you can use a screwdriver or claw hammer to pry it out. I replaced mine 2 months ago or so right after machinist did his. I reused the stake nut
 
OK.. Finally got the pinion seal out. Took some banging and pulling, but it came out. Fit the new seal in and as The Machinist said it was a bit tricky to get it in. I tried to strike the surface of the seal as evenly as I could and did it the same way you would tighten lug nuts. It was going in perfectly at first, but right toward the end it got a little collywompassed inside the shaft and bubbled a little bit on the edge as it fully seated. Its not much but just wanted to get an opinion on whether or not this may turn out to be a leak?
Secondly, after the seal was in I fit the differential flange back onto the diff housing. I noticed that no matter how hard I pushed, tapped or jiggled it it would never fully seat on to the lip without at least an 1/8 inch of a gap. I definitely couldn't get seated with just my hands but as I tightened the diff nut down it closed the gap to about 1/16. Is this normal or does it need to be fully seated on the lip of the diff housing where theres' no gap?
 
bluemax009 said:
OK.. Finally got the pinion seal out. Took some banging and pulling, but it came out. Fit the new seal in and as The Machinist said it was a bit tricky to get it in. I tried to strike the surface of the seal as evenly as I could and did it the same way you would tighten lug nuts. It was going in perfectly at first, but right toward the end it got a little collywompassed inside the shaft and bubbled a little bit on the edge as it fully seated. Its not much but just wanted to get an opinion on whether or not this may turn out to be a leak?
Secondly, after the seal was in I fit the differential flange back onto the diff housing. I noticed that no matter how hard I pushed, tapped or jiggled it it would never fully seat on to the lip without at least an 1/8 inch of a gap. I definitely couldn't get seated with just my hands but as I tightened the diff nut down it closed the gap to about 1/16. Is this normal or does it need to be fully seated on the lip of the diff housing where theres' no gap?
Click to expand...

can you take some pics of it and post for the gap?
the seal itself basically just holds the oil on the pinion flange and the metal dust cover part doesn't come in contact with the diff or flange. so ther is a gap on the metal part.

as for hitting the seal home, when you do it find a can or other item or large socket to tap it in all at once and fits all around the seal evenly. if you have a 52mm axle hub socket it fits perfectly over the seal and can be used for it.

you shouldn't have an issue if the gap seals, if you have a sloped driveway you can test overnight by parking with the seal downhill and if it leaks then you know and can pull and repeat.
 
You must log in or register to reply here.

Share this page

Back
Top Bottom