VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1937-1945 Torque Tube, Okie Bushing

So one aspect that bothers me is the situation where after installing an Oakie, the original rearmost bushing is running dry. You would think that would cause a problem

Here is my theory which I hope others will challenge.

The original rear bushing is irrelevant after the Oakie is installed. There is a rear bushing in the Oakie which supports the drive shaft. It is a new bushing running on an unworn part of the shaft so it has less clearance than between the old bushing and driveshaft. So having no lubricant to the original rear bushing does not create any problems.

Agreed. Plus I figure no seal is perfect and some lube will inevitably migrate from either end along with any lube already in the tube from it's first 70+ years of service...

OK, I finally attacked my torque tube. Almost didn't want to take it apart as the propeller shaft turned so smoothly with no play or roughness but I will rebuild this with a 3.73 since my original is 4.22. Plus we ALL want to see what is inside these darn things!

I will be posting a series of photos. Maybe wait until I get these ALL posted before commenting so they are all in sequence.

This series of pictures shows the torque tube by itself on axle stands and "Special Tool A" - some local brew. I simply removed the axle by removing the perimeter bolts and wiggling and the ring/axle assemble pulled free from the pinion and torque tube.

I was mistaken that there was no taper in any of my three torque tubes (ya I collect stuff lol). There is a taper but I had each wrapped in garbage bags and taped so the taper was not obvious. daaaa....

These photos show the shaft, tube and the bushing removal tool. the tool is cheaply made but works with care. It is shaped like a penis and is driven in past the bushing, then the metal tab is pounded in to expand the end so the bushing can be pulled. Tightening the bolt pushes the tool away from the splined shaft bringing the bushing with it.

The dowel is very short and stubby. I centre punched it and then drilled with a couple sized bits until it spun then dug it out with a small screwdriver and pliers. It would really suck to try and remove this dowel pin while this assembly was in a car, What took me 5 minutes I could see taking hours and much blood (and beer) to accomplish.

You can clearly see the both the front and rear dowels and how they are staked.

More pictures coming

Hard working with thumbnails and oldish eyes. Will post the pictures and then go back and add comments so bear with me!

Here you can see me pulling the front bushing out. It has a hollow in it for the dowel. The replacement bushing does not have this hollow. There is only a bushing. There is no seal of any kind. This is the original bushing.

I slid one of my Oakie bushings inside just for fun. It fit fine up until the last 3/8" section that was thicker, but would certainly pound into place. The genuine Oakie will pound inside the tube and be approximately 1/4" from the rear bushing, leaving the rear bushing untouched. The front bushing MUST be removed before an Oakie is installed as the original front bushing and Oakie are longer than the distance to the rear bushing and the rear bushing is held with a staked dowel.

My pictures then shift to the differential end of the torque tube. I remove the 3 set screw/bolts and then simply hammered the shaft from the front side and the whole assembly (propeller shaft and pinion gear/bearings/shims) came free and could be pulled out.

The service manual mentioned drilling a rivet out before removing the pinion but I did not see a need. There are 4 rivets holding the torque tube to the differential case. They are staggered and each protrudes inside the tube but do not contact the propeller shaft or bearings so not sure what rivet the manual is referring to. Edit: Later realized the rivet mentioned is the one holding the pinion shaft onto the propeller shaft.

Last batch of pictures. Give me a bit to type details.

Had to include an ugly mugshot of the photographer. Beard is still dyed purple at the request of my 18yo daughter who finished her cancer treatment yesterday. 6 months ago she was a full paraplegic with a stage 4 diagnosis and 5 tumors. Several surgeries including opening her spine to scrape tumor off the nerves, Chemo and lots of medical attention and she is almost back to 100% besides having less hair then me lol. Been a long year with Covid too so there's a reason this car project has been sitting still since April. This site and the people on it have kept me sane.

I compared the positions of the original style bushings beside the Oakie. The rear bushing can indeed be left in place as the Oakie is about 1/4" shorter. Strangely the replacement rear bushing is a smaller diameter than the Oakie rear bushing. The Oakie rear bushing is way bigger than the shaft so may be meant to cover various years. It was too hard to measure the original rear bushing (the original LOOKS smaller diameter than the Oakie) which I left in place as I haven't decided whether to replace it as I don't want a leak from the dowel hole.

Edit: It was later determined that there is a rubber spring backed seal rearward of the rear bushing. Will remove and post pictures later.

There was zero fluid inside my torque tube and the propeller shaft had some minor rust so my bushings have done their job for the 63,000 miles on the car. The car is a 1938 Canadian Coupe.

The Oakie seal is labelled "M101" so hoping a modern one is available. I have 3 Oakies and they all use the same seal, They are quite old. I was very surprised that there was no seal originally within the torque tube, The propeller shaft was dry as I mentioned above so the bushings were obviously enough to hold back fluid. The splined shaft does have some ridges visible in some pictures. Enough to snag with a fingernail. I assume this is wear from rubbing on the bushing.

I also showed a picturred of my 3.73 pinion so we could all see where the dowel pin? holds the propeller shaft to the actual pinion.

Let me know if you would like any particular pictures.

Finally think I've got all relevant pictures posted.

Still surprised there was no original seal in the torque tube, only the front and rear bushings. Have to check the parts manual sometime but there really isn't room at the end of the splined shaft closest to the ujoint and you can see in the pictures that the original bushing is almost flush with the torque tube so the only place for a seal would be between the front and rear bushings and there is nothing in my tube. Edit: found a rubber spring backed seal rearward of the rear bushing. Will post pictures later.

Added one final picture showing the side by side of the torque tube with dowel holes, propeller shaft, original bushings and the Oakie bushing.

Tim, great set of photos. Couple notes... there should have been a seal just rearward of the rear bushing. They were cork, so prone to disintegrating. Their purpose was to keep the transmission fluid from migrating to the rear end. My '53 Bel Air (Powerglide) had that seal disintegrate some time in the distant past. Not good to have ATF in the rear axle assembly, but when I took it apart, it was the cleanest differential I think I've ever seen. LOL.

You might want to consider going to 3.55:1 gears. My '53 cruises very nicely with that ratio, which was OE in the '50-'54 PG cars with torque tube drivetrain.

Cheers!

Doug

You made me look again Doug!!

I have seen the cork seals that go behind the rear bushing though I thought they went on trucks (at least around 1938 years). I suspect there are variations over the years and models...

My torque tube was clean inside so I dug out the Amazon inspection camera and low and behold, there is a rubber seal/spring on the backside of the rear bushing. Drat, I was hoping to not have to take that bushing out but now I have to get it into my hands.

Attached a picture I just found in the service manual (after I finished ripping things apart of course).

The 3.73 is a direct bolt-in for 1937-1939 cars as it was available in the USA built Masters. The 3.55 needs a fair amount of machine work for a 5% improvement as the later model car torque tubes are longer and the gear design is completely different. If I can fit a taller tire I can gain close to the 5% back if I need. If I couldn't go to a bolt-in 3.73, I would likely look at the 3.55. An overdrive would be nice to find as some guys really like the original 4.22 around town as it feels like a hotrod. But alas the 3.73 is soooo easy lol.

Found the rear seal with some searching. Has the small spring along the edge like I saw with my cheapo camera.

Attached a pic I found online. It cross references to National 50606 Seal

Gonna have to tear this out now that I've disturbed it. At least I finally know what's inside this pesky torque tube.

Great pictures and write up, thanks for posting. Check out National 471270 for a replacement for M101 and post what you think. I have this job ahead of me and your write up helps!

Prayers for your daughters full recovery.

Dave

I will pull the rear bushing and seal today so I have pictures of everything done. I'm tempted to make a new post eventually that is more organized and after I get other questions or question things myself - like where to get new new dowel pins. The usual vendors sell them but they are miles too long. Like to test replacement seals for fit and then post what works.

I have ordered the National 471270 seal Dave for replacement of the M101 on the Oakies, as well as a SKF 10632 for replacement of the rear bushing seal. Will see what they look like.

Attached is the service manual picture showing the line drawing of the pieces.

2nd picture are the actual pieces, including the rear bushing and rear seal. The seal is leather..

Pictures of the Oakie Bushing.

In placing it side by side with the original bushings, it offers more bearing surface than both the front and rear bushings and obviously has a seal. The rear bushing and seal appear to essentially replace the functionality of the original rear seal and bushing (even though they are normally left in place when installing an Oakie). The Oakie then provides a new bushing surface for the u-joint.

This one is dirty but shows enough detail to be useful. I positioned the Oakie in it's intended position in some previous photos so you can see the position relative to the original bushings and seal.

Tim,
That is good news about your daughter. I bought my 38 to celebrate surviving esophageal cancer in 2015.

What instructions do you have to shim your new assembly?

Great information and photos. Many thanks for sharing this level of detail.

Based on my first pass through the pictures it does look like what I expected. But it really helps to see the actual parts!

I agree that if you have the 3.73 it is it not worth all the effort to adapt the 3.55.

Not sure what you are referring to Fred. I suspect setting up the Ring and Pinion - that is much later! I just tore the torque tube apart since so many of us were questioning what was in there. The differential setup is a whole 'nother battle much later...

Sorry I didn’t mean to get ahead of you. Myself I tend to think through scenarios months ahead of time and go through all the steps in my mind. Anyways it sounds like you have a lot of spare parts! And thank you for showing us all the details up close!

Tim,
I have a copy of the Chevrolet Mechanics Repair Manual for 1937 38. It describes the use of a gear setting tool that measures the actual depth of the pinion. It appears that they didn’t document this procedure in future manuals. If you would like I can send you a copy of the article.

A friend of mine who is a mechanic and a machinist used this procedure on his early Ford. He initially used the standard process of going by the pattern but it resulted in a noisy rear end. He ended up measuring the pinion depth and corrected the problem.