Rear Differential Front Oil Seal Leak (1 Viewer)

[shack]

I observed last night a small puddle underneath my rear diff. Upon inspection and after smelling it it's definitely gear oil. I wiped it up and checked this morning and that puddle is nearly dry. No new drips. I also haven't driven my truck since Tuesday.

I've identified the drip location and based on my reading in the FSM I think its the rear differential front oil seal. I haven't touched this part of my truck before so the components and everything are all new to me.

Putting together a quick parts list here is what I have. I put a * next to the items marked non-reusable. Am I missing anything?

Plate Washer*
Oil Seal*
Bearing Spacer*
Dust Deflector*
Drain Plug Gasket*
Fill Plug Gasket*
Gear Oil

This looks like a straightforward job and I think I can just knock it out in my driveway. However you can never be totally prepared for the unexpected.

I've attached a few pictures of the problem.

 

[Cruiserdrew]

It does look like the pinion seal. Before you do anything else though, make sure the axle breather isn't clogged. If it is, as the differential heats up, it will push oil out through the seals.

One thing to realize, is that on high mileage trucks, the leaking seal often is related to a worn outer bearing, or a grove in the sealing surface of the flange itself. So the repair you do in the driveway may not last, and a full rebuild may be needed.

 

[Mandrake]

Loose pinion bearing preload can cause a leak, so if you havent already done so, engage the parking brake, put the tcase in neutral to remove any load on the driveline, then wiggle the joint to see if your pinion bearings are loose. If they are, unstake the nut and retorque and restake, then clean off all the oil and drive it a bit to see if it still leaks.

This has been the case twice for me, and I figured it was worth mentioning in case you didn't already check.

 

[unklwedy]

You may want to have a 'Ready Seal' on hand. Pinion flange may have nasty wear mark preventing new seal from working properly.
Not sure if it is wise to replace crush sleeve. I'll let others chime in.

 

[nukegoat]

If the current flange is torqued via a crush sleeve then you cannot retorque to establish pinion preload

 

[shack]

Loose pinion bearing preload can cause a leak, so if you havent already done so, engage the parking brake, put the tcase in neutral to remove any load on the driveline, then wiggle the joint to see if your pinion bearings are loose. If they are, unstake the nut and retorque and restake, then clean off all the oil and drive it a bit to see if it still leaks.

This has been the case twice for me, and I figured it was worth mentioning in case you didn't already check.

After checking for this wiggle it would be this step you are referencing correct?

 

[Mandrake]

Yep, but I guess the ones I've run across had solid sleeves if the crush sleeves can't be retorqued.

 

[Cruiserdrew]

If the current flange is torqued via a crush sleeve then you cannot retorque to establish pinion preload

X2

And I doubt you could generate sufficient force to crush a new crush sleeve while under the truck.

I once just tightened up a pinion nut on my FJ60 under similar circumstances, but it only lasted a few months and needed to be done again. I think the bearing wears, looses preload, the tightening accelerates the wear etc. But I would see the OPs leak as a sign it's soon time to think about a differential rebuild before there is too much wear on the gear set.

I have heard of adding a few thousandths in shims, then re-crusing the crush sleeve to the correct preload but have never done that or even seen it done.

If you do rebuild it, it's a good chance to add a solid collar and eliminate the crush sleeve.

 

[shack]

What is another name for the crush sleeve? I want to see where it lines up in the FSM but can't find that mention.

 

[SteveH]

Have you checked to see if your axle vent is plugged? The seal may not need replacing.

 

[Tools R Us]

Many pinion seals have been changed without removing the diff. Remove the nut and flange, change the seal, put the flange and nut back on, tighten just past the old stake mark and stake it. Most of the time it's successful, if not the diff has to come out. I would not attempt to change the crush sleeve without removing the diif and carrier to properly set the preload.

Solid collar? Unless the plan is to be a bigtime rock crawler it's not needed. History has proven the crush sleeve works fine for most of us. Most of the rigs I wheel with have them, never an issue.

 

[Prairie Swamp]

What is another name for the crush sleeve? I want to see where it lines up in the FSM but can't find that mention.

Bearing spacer. Goes in between the inner races of the two pinion bearings to provide for the proper pre-load of said bearings.

 

[shack]

Have you checked to see if your axle vent is plugged? The seal may not need replacing.

The top of my breather is all sorts of corroded and I'm not even certain how its supposed to look but all the corrosion could definitely be preventing flow i'd think right?

 

[80t0ylc]

.......I haven't touched this part of my truck before so the components and everything are all new to me.......
This looks like a straightforward job and I think I can just knock it out in my driveway. However you can never be totally prepared for the unexpected.
.......

I've condensed your post to what I think is appropriate. If I wasn't in the middle of my axle project, I wouldn't be in any place to offer advice. Sounds like your willing to tackle this yourself, so....if your gonna do it....do it right. My '94 is not my DD, so I am blessed to be able to work on it over a period of....well, however long it takes. But, my project started with your problem - a leaking rear pinion seal. So you need to check your axle breather 1st to make sure it's not clogged. Even if that's not the problem you need to make sure. But, seriously, with a 20+ yr old vehicle, whatever you're fixing is going reveal something else that needs attention. What I think at least contributed to my seal leaking was over filling the slip joint zirc on my rear drive shaft.

So dig into that rear axle and pull that 3rd member out....it's time! Get a rear axle kit from Curt at Cruiser Outfitters to be prepared for seals & bearings while you're in there. Also, get the rear axle pinion nut adjusting tool. If you haven't already, checkout and adjust your e-brake. Hey, this is an opportunity to get familiar and do stuff that probably needs to get done anyway. With the 3rd member, which includes the pinion seal, I decided to get help. Ken Francisco was my choice, but I was also using the opportunity to have some mods done and I wanted it all to get done right the 1st time.

A well maintained 80 will serve you well, for years to come. And although repairs can be expensive at times, it's still cheaper than a new rig. Plus you already know that you have a well built rig to start with.

 

[Prairie Swamp]

Yep. The rear breather on my 03 Tacoma corroded shut causing it to puke oil out the axle seals. Suggest that you run a hose from the axle breather fitting up high on the body and top it off with a lawn mower fuel filter to keep dirt and bugs out.

 

[Tools R Us]

Yep. The rear breather on my 03 Tacoma corroded shut causing it to puke oil out the axle seals. Suggest that you run a hose from the axle breather fitting up high on the body and top it off with a lawn mower fuel filter to keep dirt and bugs out.

Also confirm that the fitting on the axle housing isn't plugged up.

 

[Tools R Us]

... so....if your gonna do it....do it right. ...

Blab, blab,,,,

The job at hand is a leaking seal, stopping the leak would be doing it right? Optionally, if you're looking for a new hobby, as much expenditure of time and treasure as one wants, can be put into an old rig. But that expenditure, "fixing" stuff that is currently serviceable, doesn't necessarily make it more "right".

 

[80t0ylc]

Blab, blab,,,,

The job at hand is a leaking seal, stopping the leak would be doing it right? Optionally, if you're looking for a new hobby, as much expenditure of time and treasure as one wants, can be put into an old rig. But that expenditure, "fixing" stuff that is currently serviceable, doesn't necessarily make it more "right".

If, at the beginning of my pinion seal leak, I would have took this advice, I would have missed all the other problems I've found. Geez, Tools....our 80's are 20+ years old! If you're driving one why not get the right attitude...like realizing you're going to be spending time on it to keep it rollin' on down the highway or up the trail. How many fingers you got to plug all the holes in the dike?

 

[Prairie Swamp]

Blab, blab,,,,

The job at hand is a leaking seal, stopping the leak would be doing it right? Optionally, if you're looking for a new hobby, as much expenditure of time and treasure as one wants, can be put into an old rig. But that expenditure, "fixing" stuff that is currently serviceable, doesn't necessarily make it more "right".

If, at the beginning of my pinion seal leak, I would have took this advice, I would have missed all the other problems I've found. Geez, Tools....our 80's are 20+ years old! If you're driving one why not get the right attitude...like realizing you're going to be spending time on it to keep it rollin' on down the highway or up the trail. How many fingers you got to plug all the holes in the dike?

It's not the destination, it's the journey. Besides everyone needs a hobby. As far as way to spend time and money this beats the hell out of sitting on a bar stool or drinking beer while watching SportsCenter. For me anyway.

 

[shack]

Also confirm that the fitting on the axle housing isn't plugged up.

I have some 1/8th inch cable wire that wouldn't go through this fitting. After working it around a bit I got it through and now have a better opening for sure. So it was definitely clogged. I also tried blowing through the breather line and that was a no go.

I doubt I am out of the woods and will be ordering a new breather here shortly. I'm guessing this blockage has caused the oil to seek the path of least resistance which is the oil seal.