Rear axle seal replacement

[coolwind57]

So when I installed my rear shocks the other day, I noticed that I had some fluid of some type spinning out from my driver's side, interior-side rear wheel onto the tire.  My first thought was that I had a brake cylinder going out.  But I've detected no issues with my brakes here lately.  Fluid level is good to go.  

 

Then I recalled that I'd been hearing some slight noise from what sounded like the rear end, but I wasn't sure since I just went from mud tires to ATs a couple of weeks ago.  Aha.  Well tonight, I didn't pull the rear tire but I did crawl under and uncapped my rear diff.  Sure enough, I had to add 1/2 quart.  

 

So, without pulling the wheel and really inspecting, I'm pretty sure my axle seal(s) are bad. 

 

So what am in in for?  Mine's a 1989 stock D35.  The only thing I'd done to the diff is change the fluids about a year ago.  I don't know much about them, as I've never separated shafts/gears before.  Not sure if this is a C-clip or non.  If I'm dealing with driver's side, there's two seals in there, right?  I hadn't seen a write-up yet, so how's this going to go down?  Is it a pain?  Any tips?

[Dzimm]

I've done the seals on my D30 and it was pretty straightforward.  If your pinion seal is not leaking, I wouldn't worry about it right now because you can cause a lot of issues if the pinion isn't reinstalled properly, just not worth it imo.  If it is leaking, you'll want to do it too while you are in there.  

 

The inner axle seals are pretty straightforward though.  You will have to remove the diff/ringgear as well as the axles.  Be careful when removing the diff because there are shims on either side that must be reinstalled on the side they came out!!!! The seals can be easily knocked out with a broom handle going from the outside in.  When putting the new seals in, you'll need the tool because they must be centered and you'll want to do both sides.    It takes patience to get the seals started as it's a tight space.  Make sure to clean the axle tubes out good before installing the new seals and be careful with the bearing and sealing surfaces.  

 

If it's a c-clip axle, you'll be removing the center pin of the spider gears to remove the c-clips (easier).  If it's a non c-clip, you'd be removing the wheel and brake drum to get at the flange bolts that hold it in place.  

 

As for instructions, someone will chime in with the proper instructions or a link to some.  I haven't done the D35 so I can't offer specifics on it.

[AZJeff]

Axle seals on a c-clip D35 are a no brainer.  There are plenty of YouTube videos on how to do it.   All you will need, besides the seal, is replcement gear oil, and some gear-oil tolerant silicone gasket sealant.

[coolwind57]

11 hours ago, Dzimm said:

When putting the new seals in, you'll need the tool because they must be centered and you'll want to do both sides. 

 

This is the type of tool you're referring to, right?  Loaner from Autozone.  Just helps to get them seated squarely I assume.  

 

Fellas, I really appreciate your insight on this. 

 

I think I know what Pete would say about putting time and money into this D35....

 

I may consider just keep adding fluid as necessary until I can acquire a D44 or a 8.25 for a swap....Spend hours on the D35 or hours on an upgraded axle?....hmmm.  Something to think about. 

 

tool.webp

[Eagle]

1 hour ago, coolwind57 said:

 

I may consider just keep adding fluid as necessary until I can acquire a D44 or a 8.25 for a swap....Spend hours on the D35 or hours on an upgraded axle?....hmmm.  Something to think about.

 

 

Bad idea. You risk contaminating the rear brakes.

[Dzimm]

I made my own tool to seat the seals so I've never seen the proper one in person but that appears to be correct and yes it's just to get the seals seated squarely.  

 

It really isn't a long job, like mentioned by AZJeff, the c-clip style is a very quick and easy job.  Maybe 2 hours if the seals cooperate.  I would however recommend just getting the gasket instead of using rtv.  I've done both methods and only ever had leaks using rtv, plus the gasket is just so much easier and faster.  No pia cleanup ever again.  Make sure you get yourself a couple cans of brake clean to clean everything in the diff because it will be dirty, just don't spray it directly into the bearings to keep the oil in them.

 

Axle swap would be nice but you are looking at a weekend project with that and a few hundred dollars at least.  The used axle you buy may need a repair done such as these seals, also more than likely would need new brakes.  Regardless you'll be buying new ubolts, probably new brakes, brake fluid, new spring perches (positioning and welding the perches), ECT.  It's more involved than what it seems on the surface.  Not a hard job by any means, just much more time consuming and costly than inner axle seals.  Plus by keeping up with the maintenance on the D35, the risk of blowing it up is lower.  

 

Like Eagle mentioned, you could risk getting gear oil into the brakes rendering them useless if you let it go.  Granted one slipping rear brake won't do much as the fronts do most of the work but you have to weigh the risks with that.  

[AZJeff]

There is a nice YouTube video on how to change the wheel bearing and axle seal on a D35.   The only part you need to pay attention to is the seal part, and that starts at 1:35

 

How To Replace Your Axle Seal and Bearings

 

I have always used a block of wood to drive in the seal.  You cut the block so it's width matches the outside diameter of the seal opening in the axle housing.   The wood is soft enough to not damage the seal or the housing bore, but judicious smacks with a machinists mallet or the like will drive it in.

[Warren Mohler]

this isn't a tough job if its a c-clip pretty simple if its held with four bolts still not to bad, most have two seals be carefull with inner seal pack inside of seal around garter spring with thick grease to keep  spring in place I have had one pop off while driving it in then new seal is needed, don't  let axle drag heavy over seal when putting back in place if bearing is pressed on axle you will have to remove retainer ring to remove bearing to get to outer seal I always replace all pieces because I have no press, I use a wiz wheel to cut it all off, a heavy piece of pipe the diameter of inner race works well to knock it all back together be sure to pack bearing