The Stovebolt Site Forums The Shop Area Driveline Replacing seals on my Torque tube.

I have a 3600 with a sm420, torque tube, drive shaft to the rear end.

How far back do I need to go to get the tube off and replace the seals?

Thx Don

I think you are looking for an Oakie bushing. They are right at the transmission end of the torque tube. They come in two diameters. Getting the old bushings out and the seals can be a challenge.
https://www.chevsofthe40s.com/detail/6271/Chevrolet_Driveshaft_Oakie_Bushing_With_Seal.html

What year 3600, Don?

"I have a 3600 with a sm420, torque tube, drive shaft to the rear end."

Do you have a torque-tube and enclosed drive shaft that runs all the way to the rear end, or a torque-tube for a shot distance behind the transmission, and then an open drive-shaft to the original 3/4 rear end (what year)?

I looked back through your posts and I think you might be referring to a 1949 3600?

It has an open driveshaft into the rear end - right?
http://chevy.oldcarmanualproject.com/chevyresto/4973.htm

If you have a 1949 3600 it would have a 2 piece drive shaft.
The front shaft is a torque tube which has a bushing and a oil seal inside.
The rear shaft is a open drive shaft with a u-joint & slip yoke and a u-joint at the axle.
There is a intermediate bearing where the shafts transition from torque tube to open shaft.
The oil seal is pressed into the torque tube next to intermediate bearing.
Picture at bottom of Page (u-joint at axle not shown)
Picture of the front shaft. in truck.
Check HERE Courtesy Denny Graham, 1950 3604 Chevy truck driveline Rebuild photo album.
Check Parts Illustration Attached

If you have a torque tube like THIS I would say you have a 3100 1/2 ton truck.

xfiles

It’s a 1949 long bed. The Torque tube ends at the carrier bearing.

Yes. That’s what I have. I’m trying to fix the drips at the transmission where the tube starts. It’s not dripping at the end.

Change the cork seal and shims here Picture 1 & Picture 2
Available Here and Here You will not use the smaller diameter seal on your truck that is used on the 1/2 ton trucks.
You could call http://nwtparts.com/ ask for John he may be able to sell you everything minus the smaller diameter seal.
You need the 4 hole shim gaskets not 6 hole.
Check illustration Group # 5.572 and 5.567

Shims and Seals info.

Right.
I have the needed seals and shims. My question is how much do I have to take apart to replace them. It looks like I need to remove the torque tube back to the intermediate bearing. Is this correct?

Don

Yes
According to the manual you have to remove the entire torque tube from the truck.
Because you need to perform the necessary universal joint ball housing adjustment. Page 1 -- Page 2
The adjustment determines how many shims are needed to get the ball collar cork seal to seal correctly.
You do the adjustment without the cork seal in the ball collar.

I would split the intermediate bearing u-joint, unbolt the ball collar, unbolt the support bracket from the cross member, slide ball housing/torque tube back until it clears the front u-joint rear yoke splines.
Remove support bracket from ball housing/torque tube so you can access ball collar.
Then do the universal joint ball housing adjustment.
Install new cork seal in ball collar and place ball collar over the ball housing/torque tube.
Install support bracket onto ball housing/torque tube.
Intructions - page 2

Well guys. Thanks for the posts. I believe this is too much work for a couple drips. I’m not experienced enough for this and might get in over my head.

Thx Don

For the heck of it you could re-tighten the 4 ball collar bolts and see what happens.
That might stop the drips.
The bolts may have loosened a little over the years.
It can't hurt anything.

The manual says the 4 bolts should be torqued at 8-12 ft.lb.

Oh I’ve been after it many times. Everything’s tight. This truck sat for 7 years and everything is dried out. I’m down to three spots on the floor and this one I thought would be easy.

Don

Well guess what? After replacing all of my motor mounts. The torque tube drip went away. Not to mention banging and rattling going down the road. It’s dry as a popcorn fart.

Don

In replacing the throwout bearing on my 38 1 1/2 ton, I'm finding a lot of other things that need to be dealt with (go figure). The rear seal of the front ball joint seems to have originally had a felt seal. The replacement FelPro kit that I got has a rubber type seal ring that is almost twice as wide as the gap between the two steel rings where the felt seal was originally. I find it impossible to insert the new seal ring. Is this the wrong seal or do I just not know how to squeeze it in? I'm wondering if this seal is actually for the back ball which has a screw on cap to compress the seal.
Now that I think about it, the back ball looks like it would easily replace the front ball and is a much better setup for the back seal. Has anyone tried replacing the front ball with a back ball that has the screw on cap at the end?

Cwalling

Does your drive train look like this:

Chevrolet's 1938 Shop Manual

Front Propeller Shaft and Housing - 1929-40 Top picture

Yes. Basically figure 43 from the shop manual.

Cwalling

Is the front ball housing and the rear ball housing identical ?
Is the front ball collar and the rear ball collar identical ?
Is the front screw on retainer cap and the rear screw on retainer cap identical ?

The front and rear ball housings are different. Although the general dimensions appear to be the same, the rear housing has a screw on cap. The front housing does not have this cap. It is all one piece with a lip on the back that holds the seal.

There are different ball housings, some have the lip, newer ones have the screw on cap.
You just happen to have both, probably because of the extended driveline, with the intermediate support bearing.

Most parts suppliers only provide the screw on cap type oil seal, in their Torque Tube Ball Seal Kit.
The kit comes with a ball collar cork oil seal, 4 paper/gasket shims and a screw on cap rubber or cork oil seal. Picture
I have never seen a oil seal for your lip type ball housing. But I know someone that might have what you need, keep reading.

The original front ball housing (with lip) oil seal was felt, some parts suppliers may have a cork oil seal.
1938 1.5 ton truck U-joint ball housing part # 353896 (check 1st picture)

The original rear ball housing oil seal (with screw on cap) was probably felt or cork.
The newer screw on cap oil seals are usually cork or rubber.
The rubber oil seal in the felpro kit, is for the rear ball housing screw on cap.
Some rubber oil seals can be quite wide, Picture it will work just as long as there is enough threads in the cap.
I think the 1938 1.5 ton rear ball housing part number is 602688. (check 2nd picture)

Both ball housings use to 2 steel O-ring washers.

Because you have a older and rarely seen driveline,
I would talk to John over at:
Northwest Transmission Parts
13500 US Highway 62
Winchester, Ohio 45697
(800) 327-1955
nwtparts.com

Tell him what truck you have and he should be able to set you up with the correct front ball housing (with lip) oil seal.
He just may have a newer type of oil seal and some tips for installation.
I think most ball housings have the same tube inside diameter and ball outside diameter,
which means lip type and screw on cap type can be interchanged. John would know.

I'm curious, are the 2 steel washers in the front ball housing
split or cut so you can get them out of the housing.? Picture (click on picture to enlarge).

This Parts illustration is for powerglide transmission but some of the ball housing parts are interchangeable with other GM vehicles.

Let me know if Northwest Transmission Parts had what you needed.

xfiles

Great information! Thanks for for the detailed response. The Two washers are solid which seems like a really poor design. They could have used a snap ring or retainer and made things much easier. Or just used the screw on cap like the rear ball. I’ll call John and see if he has the correct seal for me.