Rear axle seals

[Mertz]

I inserted the axle into the rear end and on the passenger side and there appears to be an inner seal but there does seem to have one on the drivers side.    Is that because the diff vent is on that side?

[lostviking]

Not sure. I suggest taking a look at the exploded view in your parts book.

[Dodgeb4ya]

There should be a inner oil seal on each side of the axle housing.

Then one more narrow grease seal in each rt/Lft backing plate.

[Mertz]

I have the inner and outer seals but there appears to be something near the differential that the axle slides into on the passenger side but not the driver side. The diagram in the manual shows both sides the same. I did run some shop towels through each side to clean them but I’m sure I left nothing behind. I guess I’ll pull the differential and see if I left something behind. 

[Veemoney]

It could just be you are having trouble aligning the axle splines to the mating splines in the center section. If you push the axle in and it hits something metal to metal try tilting the axle some to get the inside end centered while rotating it. If you are bumping into  metal you will hear it like the light tap of a hammer on solid metal. If it sounds like your bumping rags well you know what you need to do. You should also be able to use a small diameter Maglite to look down the tube to see the obstruction.  

[Mertz]

The drivers side goes in just as you described. I have to tilt the axle to get it to align. The passenger side seems to have a ramp that it slides on to and I can feel resistance as I push it in all the way. It takes a strong final push to get it all the way in. I’ll pull the pumpkin next week and have a look inside. 

 

[Mertz]

The drivers side goes in just as you described. I have to tilt the axle to get it to align. The passenger side seems to have a ramp that it slides on to and I can feel resistance as I push it in all the way. It takes a strong final push to get it all the way in.

 

Update. Looked down the end of the rear end and there was a shop towel left inside from when I cleaned the housing. What a dummy I turned out to be. Should have seen it when installing the pumpkin but it was up high.  

 

[Veemoney]

I think pulling the center section is a good idea and should be easy since you had the axles out. Will give you a chance to look it over and replace the pinion seal if you have not done so already.

Here are some other things that can also cause the situations you mention below if you do not find anything wrong in the housing or center section. The picture that follows shows a car axle at the top with a truck axle below it. You can see the taper and seal surfaces with diameters marked. There is ~1/16th difference or .030" a side on the OD of the inner seal surface.

1. The axle tapers up from the splines to the hub. Once you get the axle so far in you would likely feel the axle moving up as it ramps up at the inner seal/axle contact point going through the seal.
2. Not sure if you are working on a truck. Since it takes a strong hard push at the end that could signal an issue with the inner axle seal since that surface is short and comes into full contact at the very end when your pushing the maximum diameter through the seal. (possible distorted/damaged seal or a smaller ID seal used that is for the car axle.) 

20 minutes ago, Mertz said:

The passenger side seems to have a ramp that it slides on to and I can feel resistance as I push it in all the way. It takes a strong final push to get it all the way in.

[Mertz]

The rear end was pulled and examined and appears to be in very good condition.  There are no wear marks on the gears and everything appears tight. This is on a truck. I have installed new seals and still need to replace the axle bearings. 

[Veemoney]

Good so far, do you have the inner seal part number/s you used? Couple things to check also while you have it apart.

1. Slide passenger side axle into the center section while you have it out to confirm no issues or burrs. Should slide in nicely.
2. Slide axle into passenger side housing. Should feel minimal resistance when you reach the sealing surface. 

[Mertz]

I got the seals from Roberts specifically for my truck. Passenger side slides in very nicely and the shop towel created a bit of resistance on the drivers side.