1/2 Ton Rear End Rebuild

[timsresort]

I am looking to rebuild a noisy 8-3/4" 1/2 ton rear end and started looking around for parts, and it appears limited. And no, I have not reached out to my normal parts vendor yet. Does anyone know if the supply of stock 4.89's is limited to NOS or used? I.e. no one is making them? I have seen the seals and spiders etc, and I assume bearings are available from Timken, but no gears. What has everyone been using? Have we just been lucky enough to use original serviceable gears?

[napavalleyartillery]

Well if you are sufficiently motivated there are at least five or six in place differentials sitting out in the boneyard. You are welcome to investigate at your leisure. Price would be right.

Send me a pm if interested.

Barry

[timsresort]

Well if you are sufficiently motivated there are at least five or six in place differentials sitting out in the boneyard. You are welcome to investigate at your leisure. Price would be right.

Send me a pm if interested.

Barry

Thanks Barry, I appreciate the offer. Let me get it open and see how bad it is, and I'll get back to you.
Tim

[timsresort]

Well, it was such a fine fall day, I decided to get to the bottom of the noisy rear end. Took it for a drive, 40 MPH or so down a hill, on coast I have some noise. To eliminate the transfer case, I shifted the rear end into neutral (I have a NP 205 transfer case), front end into high, locked the hubs, and continued. No noise, so rear end. Popped the rear cover, nothing terrible, except a lot of magnetic oil. Backlash isn't horrible, maybe 10-20 thou. But what is noticeable, is the slop in the side gears to spiders, I can turn the yoke an inch or so. So out it comes.

It's striking if you usually work on Dana axles to see a banjo housing empty.

[timsresort]

A couple small problems right away. I think I forgot I have one 1/2 ton axle and one 3/4 ton. Dug around and found the correct shaft for when this gets reassembled.

Next, I noticed the U joints had some play, did not have any new ones in stock, so will order some up. Luckily this truck uses Detroit style not mechanics, which are getting expensive. BTW, Moog 305 or Spicer 53251-X works for the joint, but surplus NOS are the cheapest.

Then, I have oil getting past the axle seal, which is diluting the wheel bearing grease, so I will look at those. The seal problem is likely from the groove in the outer spindle nut seal surface. Also, ominously noticed the magnetic silver paint dripping out.

I painted on some gear marking compound to see what the mesh pattern looks like. Hmm, it's in the middle, which is good, but shows a sharp diagonal wear across the drive side of the tooth.

And looking closer, on the unmarked teeth, you can see wear on the drive face of the teeth. I'm thinking the pinion is giving up, hence the silver paint.

[timsresort]

Not having a lot of luck on parts, so decided to look in my stock for whatever I could find. I have no 1/2 ton assemblies left, but did find new (1952) diff gaskets, seals, and axle gaskets.

I have had a few very generous offers to look at used 3rd members, and I think that is where this is heading.

[timsresort]

Having located a good used 3rd member, I decided to pull out the housing for clean up and paint. I started with capping the brake line and pulling the drums.

This is the outer spindle nut with the groove allowing oil into the hub.

Housing out, and now I can feel the worn spring bushings, so they will get replaced.

A quick pressure wash and clean up with a wire wheel, and I won't have to set up for blasting. I think this will be fine.

If this axle could tell stories...

[zepher11]

Looks like a fun project. I take it those scrapes/gouges on the rear end housing are on the bottom? Built Dodge tough!

[D.R.H.]

I agree with Zeph. This is making me miss my 1/2 C. Car. Nice write up Tim, can't wait to see it progress.

[Dozerman51]

I found that when installing new spring bushings, it is so much easier to freeze them overnight so they go in much easier than having to really pound them in if installed at room or outside temp. Just a tip and you might already know this.

[timsresort]

Looks like a fun project. I take it those scrapes/gouges on the rear end housing are on the bottom? Built Dodge tough!

Yes, on the bottom. I might be responsible for some of it, the time I took it up to 11,000' in the Eastern Sierra.

[timsresort]

I agree with Zeph. This is making me miss my 1/2 C. Car. Nice write up Tim, can't wait to see it progress.

Thanks Dave. I'm not doing a big project like Zeph this year, just some nagging little stuff like this that would be fun to knock out.

[timsresort]

I found that when installing new spring bushings, it is so much easier to freeze them overnight so they go in much easier than having to really pound them in if installed at room or outside temp. Just a tip and you might already know this.

I have done that with ring gears before. Thanks for the tip, I got the springs out today, and ordered up the bushings.

[timsresort]

It has been a while since I pulled leaf springs out of a Dodge, so had to refresh my memory on getting the pins out. The book shows using tool DD-431.

Lacking that tool, and with some advice from Zeph, I came up with running a 3/8-24 cap screw into the zirc threads with a jam nut, so I could wiggle it out with vise grips. Worked like a charm. A slide hammer would also be great, except with the body on, there is not room in there. I was grateful that they were not rusted/frozen in place and slid right out. Note the remnants of red paint, highlighting a lube point.

Once on the bench, I can see the bushings are toast. The rear end was the one area I skipped 10 years ago when I wanted to get it on the road. Don't want to rush into these things.

[zepher11]

It has been a while since I pulled leaf springs out of a Dodge, so had to refresh my memory on getting the pins out. The book shows using tool DD-431.

Lacking that tool, and with some advice from Zeph, I came up with running a 3/8-24 cap screw into the zirc threads with a jam nut, so I could wiggle it out with vise grips. Worked like a charm. A slide hammer would also be great, except with the body on, there is not room in there. I was grateful that they were not rusted/frozen in place and slid right out. Note the remnants of red paint, highlighting a lube point.

Once on the bench, I can see the bushings are toast. The rear end was the one area I skipped 10 years ago when I wanted to get it on the road. Don't want to rush into these things.

Ahhh...your photos reminded me that I used a large socket, nut, washer and bolt to pull some of the pins out. I did use a slide hammer on one or two, but the body was off. Would be difficult to access as you mention with the body on.