The Stovebolt Site Forums The Parking Lot Tons 'o Fun Rear Axle Difference AD 1-Ton?

Question for the gurus ... On the pre-Huck brake AD 1-ton single-real wheel axles (3804 truck), I went to the NAPA web site and for the original '49 3800 axle, SKF (seal manufacturer) lists kits for the HO52 and HO72 axles. I'm guessing the HO52 axle is the single rear wheel and HO72 is the dual rear wheel axle. Is that true? What I'm really asking -- which seal kit should I order for the a '49 3804?

Grigg -- If you read this, I can't remember which axle is which of the two I have on the shelf here ... One of them is Handsome's original and the other is a '54, ja?

John, I just looked in the Timken catalog and got pinion seal 411330N for 46-59 HO52 and HO72.

For wheel seal, I got #2081 for all years, including the 72-present 14 bolt axle.

The HO52 is the 3/4 ton axle, rated at 5200#, the HO72 is the 1 ton axle, rated at 7200#. I believe the main difference is the brake size, perhaps outer bearings on some years/models. I have seen both versions in single and dual wheel, as dual wheels were an option on 3/4 tons in some years.

John, I know you have the Handsum's old 52 axle, not sure about the 54. Pictures of both I might recognize the correct rust color on the 52 if different from the 54...

That's interesting -- So it's the same part for both axles? That's good to know.

This can get confusing as we are going to do the pumpkin swap at Homecoming and document it for a Tech Tip. We are removing the original center section of the '49 1-ton axle (pumpkin,ring and pinion gear) and replacing it with the center section from a '72 3/4-ton axle to get the 4:11 gears. So I am having to keep parts straight for a '72 3/4-ton Pinion Seal and the '49 wheel seals. I'm hoping the bearings are all good as I don't relish the idea of tearing into the ring gear assembly ... although it would make a more complete tech tip ...

Thanks for all the info and helping me keep straight.

Grigg, I'll get pictures. And then I will tag the axles. I'm trying to remember where this other one came from ...

Here's Timkens catalog. P114-115 and P125-126.

Looks like things stayed pretty much the same. A couple varitions in the bearings, that's about it.


http://www.timken.com/EN-US/product..._Seal_Application_Catalog_1989_older.pdf

Not to hi-jack but this is EXACTLY what I'm up to. I found a '72 C30 truck in a local yard today. The stamping says RAK01122 on the rear diff. Guy says that makes it an open drive rear for '72.

Is THIS the magical one I need? I don't care if it is an open diff or not, I'm not pulling the house over. Just trying to get my 3804 "Ivan" to move a little better.

You don't have a torque tube in your 1 ton now do you?
A 72 1 ton rear is most certianly an open driveline, no torque tube. So you could swap center sections but you'd have the same setup is my guess. Other than a possible gear ratio change.

If you want a faster gear ratio than what you have now then first figure out what that is and what the ratio is in the axle you're looking at. While the new one probably is faster geared don't just guess and count on it, lots could have been changed on either truck in the past 40 or 60 years.

Grigg, the stamping on it is RAK01122 and according to the look up at the yard the RAK is supposed to indicate that it is an 4.10 open diff. I just want to make SURE it is the right set. I want to move a bit faster than 5.13 or whatever I have.

I'm looking to do the swap and keep my partial torque tube and all.

My current diff is most definitely in the 5.xx range. Tops out at 49 and it is ugly over 45 just like my old 53 dump truck.

Dan,
Here is a link to the 67-72 Chevy Truck site which references the axle prefix code, the post is 10 posts down. According to the ref, the RAK prefix for 1972 is a 4.10 open dif. When the wrecker is talking about open diff he was referring that it is not a posi. Your best bet is to count the teeth on the ring gear to make sure, as Grigg says you never know what someone has done to a truck over the years.
The link is: http://67-72chevytrucks.com/vboard/showthread.php?p=6534796

Hope this helps
Dave

Thanks. I knew it wasn't posi and I don't care about that. I just wanted confirmation. I don't want to spend a bunch of money on something I can't use. I'm going to take my spare 3/4 ton rear with me when I go out there to pick it up JUST to be safe. And I'll probably pull the rear cover off so I can look at the numbers like Grigg showed.

Good luck, Dan! And hi-jack away (thread hijacking is the official sport of Stovebolt.com )

On the ring gear we've found, the ratio is stamped backwards on the ring gear (on the side, inside of the teeth). i.e., "10. 4" for a 4.10:1 ratio. Hope that helps.

Thanks, Boss Man. I'll keep you posted on what I find. Got to remember to have the bat op impact charged when I go out there so I can make quick work.