The Stovebolt Site Forums The Shop Area Engine Shop Driveline Leak

I just discovered a new leak on my 1950 3/4 ton. There is fluid leaking from the drive shaft where it mounts to the frame. Since this is a 3/4 ton, it has an open drive train. However, the front half of the drive shaft seems to be close while the back half is open.

Since the drive shaft appears to be a two piece, I assume there is a bearing where the shaft mounts to the frame and this is where it is leaking.

Can anyone give me help on how to fix this and tell me how difficult it is?

Michael I have the same exact truck. If it's original it will have a torque-tube front shaft. Notice the ball & socket type joint on the tail end of the transmission. That covers the front U-joint/trunnion-bearing. Oil from the trans lubes the U-joint. There is a thin metal tube that covers the drive shaft back to the carrier bearing. There is a seal back there that leaks. I think the Truck Shop Manual has an illustration of this. I don't know if anyone repops that seal. Good luck.

I was hoping there was just a seal but don't know for sure and didn't know how big of a deal it was to fix.

The shop manuals from GM have always been good but this 1950 manual is not very thorough.

Have you had to replace yours?

The 50 I have now has decades of caked-up oil and dirt that have "sealed" it up. My previous 50 3/4-ton leaked bad there. I remember a post about this problem approx. a year ago. Guy posted a picture of the underside of his truck and he had a small tin bucket or paint can wired up under the dripping joint. :p

Mine leaked around the threaded collar on the ball housing. I undid it and wrapped plumbers teflon tape around the threads and it is now dry. If it is coming out of the end of the ball housing then a new seal is needed.

I noticed that there is what appears to be a rubber seal that is torn and sticking out about an 1".

If that rubber seal is sticking out of the end of the ball housing by the threaded collar then it has to be replaced which entails undoing the 4 bolts at the rear of the trans, un bolting and removing the u-joint then taking the housing off. The seal goes in that threaded collar. Sometimes you will find a thin metal ring the same diameter as the seal. I think this may hae been used to hold the old felt style seal in place. Having said all this I am assuming you have a torque tube driveline.

Oldblu49, his 3/4 ton has the two piece shaft. Front half is enclosed, rear is open.

I would recommend removing an reconditioning the driveshaft. That is the only way to replace the ball gasket. I was able to purchase the seal and gaskets at my parts store. Check your carrier bearing, I had to replace mine. Also there is a rubber cushion around the carrier bearing, you will have to get it from one of the restoration parts dealers.

The seal I'm speaking of is the one where the drive shaft is mounted to the frame. I assume that is the carrier bearing?? That is where the leak is coming from. I called a couple of transmission shops and they said they could fix it but it depends on the availability of parts. The manual describes how to fix it but it sounds as though you have to have a press. I also don't know what parts to order.

?????

Inside the housing at the carrier bearing there is a drive shaft torque tube seal, which is the part that is leaking. Other parts needed will be the carrier bearing rubber bushing and the universal joint housing and bell gasket set. You might also need a carrier bearing and universal joints. Of these parts, the only one that I know for certain that has to be purchased from the specialty vendors is the carrier bearing rubber bushing, and possibly the torque tube seal. The bell gasket set is still made by fel-pro. The carrier bearing should be available from a local parts store, but I cannot recall for certain. The universal joints that are exposed are available through a local parts store, but the enclosed u-joint (at the tranny) is not available, as far as I know.

The driveshaft is not that difficult to rework. It can be done without a press, but some mechanical aptitude is needed. If I were taking it to a shop, I would at least get the seal and the cushion before I went in. You aren't too far from Chevy Duty, they should have the parts in stock. Also Jim Carter and LMC are in the area.

If you need a good mechanic, I do know of one in Olathe, he rebuilds 67-72's on the side. Back channel me if you would like a contact.

Hey Michael or Fred,

My 1950 3/4 ton Chevy torque tube is also leaking at the carrier bearing. I have been trying to find a source for the drive shaft torque tube seal. All of my local sources say that the seal is not available. Please let me know where I can find one.

Thanks

It was 5 years ago that I got mine, parts store had it on the shelf, Felpro, but I don't know the number. If your's doesn't show it in the books, you're stuck with making your own. The Felpro web catalog now only goes back to 62.

I tried some of the on-line shops, found a set at American Classics, GKT-05 for $25. Says it fits 37-54 1/2 & 3/4 long beds. It's at least worth a phone call.

Mike try the filling station in Lebanon Oregon

www.fillingstation.com

Thanks Guys,

I'll give them a try.

I posted this a while back but here it is again. It may of some use to you. I bought a replacement bearing and rubber cushion for my 51 1 Ton and according to my information, it is the same bearing as the 3/4 Ton.
Bearing:
Number wriiten on Box 906879
bearing stamping SXF 6207 VBE
also replaces 8A-1225-A
Ford Pass(EXC. S. D. & S.W.)49-56 Merc 52-55 rear wheel bearing

Replaces 906879 (5.430)
Chev Trk Frt 3/4 & 1 T 46-59 EXC D.S. & E.S.

There is more information on the package about other models.

The rubber cushion is a DOAN 35-2036