Rear Diff - Pinion Oil Seal (1 Viewer)

[Irish Reiver]

Came home yesterday from a work trip and found this nice little puddle waiting for. It appears to be running from the pinion seal. The passenger side area has a liberal covering of gear oil so my guess is that it leaks more when been driven than when it is just sitting. I checked the diff breather and it is clear. The FSM details the replacement of the seal but goes all the way to bearing and bearing spacer. A search on Mud brings up a few posts from many years back but it isn't clear to me if I can get away with replacing just the seal of if it makes sense to also do the bearing. Also can this be done with the axle still under the truck?
This is one task on my cruiser that I have never attempted so any help and guidance is appreciated. Also I should point out that the truck has 325K miles under her belt.

 

[Malleus]

Yes, but it's a PITA. You have to break the peen on the nut, and that's a chore under the truck.

 

[JoeCova]

It can be done under the truck and you don’t "need" to replace the bearing. You could technically try to reuse the bearing spacer as the axle nut torque is generally less than crush torque. But if you get it all back together and the preload is off then you would need a new bearing crush sleeve which would require you to pull the bearing anyway so you might as well replace it.

I think the FSM goes through the whole process so people aren’t doing double work by reusing old parts.

Option 1:
Remove nut
Pull flange
pull seal
Replace Seal
Install Flange
Torque Axle nut to 181
Check Preload to spec (knock on wood it's in spec)

Option 2:
Follow FSM and replace bearing and race, crush sleeve and seal.

Option 1 is easy but carries the risk of having to do option 2 anyway. Option 2 will be correct but will be a pain in the ass to get the bearings in and out. I recommend putting new bearing races in the freezer overnight and heating the diff prior to install.

Lastly, double check its not leaking around the diff housing seal, those commonly leak and sometimes you need to retorque the 3rd member nuts. The pinion does hold some oil with the oil retainer but its not a lot so the fact that THAT much is leaking just by sitting seems like it might be the housing seal.

 

[BILT4ME]

Came home yesterday from a work trip and found this nice little puddle waiting for. It appears to be running from the pinion seal. The passenger side area has a liberal covering of gear oil so my guess is that it leaks more when been driven than when it is just sitting. I checked the diff breather and it is clear. The FSM details the replacement of the seal but goes all the way to bearing and bearing spacer. A search on Mud brings up a few posts from many years back but it isn't clear to me if I can get away with replacing just the seal of if it makes sense to also do the bearing. Also can this be done with the axle still under the truck?
This is one task on my cruiser that I have never attempted so any help and guidance is appreciated. Also I should point out that the truck has 325K miles under her belt.

View attachment 3795672

It's not bad to do.

I did mine about 350K, under the truck in the driveway.
Buy a new Toyota seal.
Take the seal to Lowe's or HD and buy a PVC pipe coupler that is the correct diameter to press in the seal. This becomes your spacer to pound on since the pinion will be in your way. I think it was a 3".
Remove the DS
Use hammer and chisel to open up the existing dimple in the nut.
Use an impact to remove the nut.
Pull out the yoke. May need a puller.
Clean the area well.
Remove the old seal. I have an eagle claw to do that, but I think I had to get creative, I don't recall.
Install the new seal with your new tool make sure the bearing and crush sleeve are still in place after pounding on the front, it tended to want to allow the pinion to slide back into the diff and the bearing, crush sleeve, and washer would get out of line.
Reinstall the yoke.
Screw on the nut and tighten with an impact until the nut is 1/2 the width of the keyway on the pinion tighter than when you took it off.
Dimple the nut.
Install the DS .
Enjoy.

Feel the pinion slop (backlash) before and after to make sure they feel the same.

I now have 372K on it and it's one of the best and easiest fixes I've done with immediate results.

I've done this on front and rear.

 

[cruzinfj1]

Good time to change the gear oil seeing how its already low..... Might as well do the front and the tcase while youre under there.

 

[cruiseroutfit]

Be sure to inspect the deal surface on the pinion flange itself. It’s getting very common to have a discernible groove in the flange where the lip of the 38935/38047 seal sits.

While you can use a speedy sleeve, the flanges are ~$42 for a new Japanese flange. If you end up needing one, we’d love to help!

Pinion Flange 27 Spline - Fits 1/1978 - 1/90 4x/5x/6x/7x & 1/1990 - 97 8x Rear Applications (PN60010/30)

Toyota Land Cruiser Pinion Flange

cruiserteq.com

 

[Irish Reiver]

Thanks everyone for the feedback. I plan on following the guidance from @BILT4ME and @JoeCova and will definitely pay close attention to any possible wear grove on the pinion flange. Hope to get this started and hopefully finished today. Will report back on progress.

 

[Irish Reiver]

Good time to change the gear oil seeing how its already low..... Might as well do the front and the tcase while youre under there.

The real pisser for me is that I did the axles and seals on this truck about a year ago. I only got to the point of being able to drive it less than a month ago. Gear oil has about 500 miles on it. Probably my mistake was letting the diff sit for a year with no gear oil in it. Possibly allowed the seal to dry out a bit. I'm not so motivated to start on the other seals even though it makes sense. The dice have been rolled...

 

[BILT4ME]

The real pisser for me is that I did the axles and seals on this truck about a year ago. I only got to the point of being able to drive it less than a month ago. Gear oil has about 500 miles on it. Probably my mistake was letting the diff sit for a year with no gear oil in it. Possibly allowed the seal to dry out a bit. I'm not so motivated to start on the other seals even though it makes sense. The dice have been rolled...

Did you use Toyota seals in it or a different brand?

For things that are painful to get to I make sure to use Toyota.

 

[Irish Reiver]

Did you use Toyota seals in it or a different brand?

For things that are painful to get to I make sure to use Toyota.

I use toyota wherever possible. Everything on the axles is all Mr.T. I ordered most of what I need for this little job from my local dealership and they are usually pretty quick with getting the parts I need. Currently in the process of tearing it down.

 

[Irish Reiver]

Pulled the pinion flange and this portion of the seal just fell out. I think I can spot why it was leaking. Also there is a decent groove worn on the seal surface so new pinion now on its way.

 

[Irish Reiver]

I managed to complete the job over the weekend. New toyota oil seal, oil slinger and pinion flange. Racked up about 50 miles as a test run and this morning it is leak free .


On the down side I now notice a whine from the rear which happens under acceleration and disappears when I coast. I need to try and isolate if this the pinion bearing or maybe just a UJ. I don't know if the whine was there before I changed the pinion oil seal as I had very noisy MT tires fitted. I now have a set of standard road tires from my other Cruiser fitted which are super quiet and possibly allowing me to hear things not previously apparent.

 

[JoeCova]

I managed to complete the job over the weekend. New toyota oil seal, oil slinger and pinion flange. Racked up about 50 miles as a test run and this morning it is leak free .


On the down side I now notice a whine from the rear which happens under acceleration and disappears when I coast. I need to try and isolate if this the pinion bearing or maybe just a UJ. I don't know if the whine was there before I changed the pinion oil seal as I had very noisy MT tires fitted. I now have a set of standard road tires from my other Cruiser fitted which are super quiet and possibly allowing me to hear things not previously apparent.

View attachment 3798884

Awesome stuff, glad you were able to take care of it.

I always tend to be slightly hyper sensitive to noises in areas I just got done working in. It's possible that whine was there all along or it could be the bearing. Hard to say without a video for us to hear. As long as your pinion bearing preload is in spec the bearing should be seated correctly.

 

[BILT4ME]

I managed to complete the job over the weekend. New toyota oil seal, oil slinger and pinion flange. Racked up about 50 miles as a test run and this morning it is leak free .


On the down side I now notice a whine from the rear which happens under acceleration and disappears when I coast. I need to try and isolate if this the pinion bearing or maybe just a UJ. I don't know if the whine was there before I changed the pinion oil seal as I had very noisy MT tires fitted. I now have a set of standard road tires from my other Cruiser fitted which are super quiet and possibly allowing me to hear things not previously apparent.

View attachment 3798884

Typically, a whine during acceleration and not deceleration is a pinion bearing, but it can work exactly the opposite as well, but both can be the pinion bearing preload. How tight did you get the yoke? Since you used a NEW yoke (flange) you no longer have a reference point to the previous preload, so if you reused your crush sleeve, you must go by relative torque instead of the reference of the keyway in the shaft to the nut.

The actual thickness of the flange neck may vary by 0.001" or 0.002" and will change the preload of the pinion and thus may cause the whine. It actually moves the teeth of the pinion from its previous operating location and will be wearing on a slightly different area. is it catastrophic? No. It's annoying, but you may get many more years out of it. I had a rear diff on my Studebaker that whined like an Oliver Tractor on the highway to the point you couldn't have a conversation inside the car while driving. It never failed, but was annoying as hell.

You may want to go back and check the backlash of the pinion as well as the torque on the nut to make sure they are where they need to be. Use an Infrared gun to check front bearing temps of the housing after a ling drive to make sure you're not seeing a lot of heat. Should be sub 130°F in that area. I have not checked mine for a reference point. Make sure the pinion doesn't move in and out during rotation from forward to reverse (accel to decel), as that movement is what can cause damage.