1926 Chev Touring Drive line Problem

[Steve Seguin]

A friend of mine has a 1926 Chev Touring and the propeller shaft inside the torque tube has disconnected at the front of the differential. He had been moving it in reverse and then shifted to 1st and it wouldn't move. He thought the transmission failed. He did not hear any noise such as a snap or bang. I jacked it up and removed the back wheels and rear diff inspection cover, to check the axles. Axles are fine. I pulled the front of the torque tube from the transmission tail stock, and the tranny is working fine. The problem seems to be where the propeller shaft attaches to the pinion gear. I have a manual that shows the all the parts but not how it is attached. The torque tube outer housing is riveted the the front of the differential casing making access to this area impossible. I'm not sure if something has broke or just disconnected. If any of you mid 20's Chev owners have any ideas on what my next step would be or have experienced this before, I could use a little guidance and appreciate any suggestions . My name is Steve and I live in Kingston, Ontario, Canada.

[Vintageben]

I would say more likely then not the tail shaft has broken at the pinion. I had this happen to me once and there was next to no noise when it let go, it’s a fairly common problem. There is 3 grub screws on the diff housing that hold the tail shaft in place. Hope this helps if you need more info let me know.

 

[Steve Seguin]

Thanks for the reply, I highly suspected this is the case. Do you know if the diff can be removed from the housing while on the car. If so, does it come out of the back or front of the housing. The manual shows removal of the entire rear end from the springs which would require raising the back of the car.

[Vintageben]

So you can remove crown wheel and pinion through the back. Obviously you have to remove the axles etc for this to be achieved but you can not remove the whole assembly as one piece through the back you have to split the uni behind the gear box and drop the torque tube remove brake rods etc as well then you can remove the torque crown wheel pinion assembly. 
If it were mine I would probably just remove axles then crown wheel so I could get at the offending parts. Then find a good prop shaft and put the pinion and bearings on it then reset backlash etc.
Have you got a workshop manual or just a owner hand book. The workshop manual is really comprehensive and helpful for this process.

[Steve Seguin]

6 hours ago, Vintageben said:

So you can remove crown wheel and pinion through the back. Obviously you have to remove the axles etc for this to be achieved but you can not remove the whole assembly as one piece through the back you have to split the uni behind the gear box and drop the torque tube remove brake rods etc as well then you can remove the torque crown wheel pinion assembly. 
If it were mine I would probably just remove axles then crown wheel so I could get at the offending parts. Then find a good prop shaft and put the pinion and bearings on it then reset backlash etc.
Have you got a workshop manual or just a owner hand book. The workshop manual is really comprehensive and helpful for this process.

I have reprint of a 1925-1926 Chevrolet repair manual that covers the more common problems. It has the section on the differential and axles but seems to be lacking some details. It is only 129 pages. I don't know if it is the same  as a workshop manual. I have already disconnected the torque tube at the gearbox and removed the rear inspection cover from the diff. I will pull the axles and crown wheel next and go from there. Do you think the prop shaft could be repaired or will we have to source a new one and where would we find one?

[Steve Seguin]

Update, today was our lucky day. We found a used prop shaft, in great shape at a classic auto salvage yard near by. Roblin's Garage has been in business since 1930 and they have a barn full of used and NOS parts dating back to probably the 20's. They have a Web site but most of the vehicles have been sent to the scrap heap in the last few years.The old shaft had broke on tapered section where the pinion gear attaches via a woodruff key. I will now do some parts cleaning and start reassembly along with adjusting the backlash.

[Steve Seguin]

Good day, 26 Chev is back together and working well. Did the reassembly through the rear of the differential. Car is back on the road.