First thing that was required was to remove the entire rear end of the drive line.

Jack up the car, put it on stands, remove the rear fenders, remove the spare tire mount, disconnect the brake rods, remove the “U” bolt brackets at the axle and spring junction, and roll out the rear end without damaging the end of the drive shaft.

Remove the rear fenders.

Jack up the rear end and put it on jack stands.

Roll the rear end out from under the car.

The entire rear end is removed. A white plastic collar fastened over the square slip joint end of the drive shaft for protection.

I went about disassembling the torque tube and differential carrier.

The torque tube, differential carrier and drive shaft are suspended from the engine hoist.

JB Weld is not going to fix this.

This used to be one piece.

The torque tube was in two pieces. What other damage occurred when it broke?

The drive shaft bent a bit. The ring and pinion gears are galled and chipped. A sleeve that was grafted INSIDE the original torque tube was cracked in half. A stabilizing tube added OUTSIDE the original torque tube was split as well. This was fairly major mechanical carnage.

The drive shaft after turning some of the bend out. Still not really straight.

Ring gear chipped and heavily worn.

Ring Gear and pinion gear inside. Note the severe galling on the surface of the pinion.

My initial thought was to simply stick what was broken back together. (This is close to a “JB Weld type fix.) But that really would NOT be a fix. This torque tube had already been broken once before. The welding and grinding on the exterior of the tube proved that. There was also a substitution of a modern bearing for the original Hyatt roller & cage type bearing just forward of the first break and our new break in the torque tube. After considerable searching online, discussions with restoration experts, and consultation with the Jolly Boys (our Saturday lunch gathering) of the La Jolla Regional Group of the Horseless Carriage Club of America, I came to the conclusion that I could not simply patch up the break in our torque tube. I would have to engineer and splice in some sort of radius rod apparatus to reduce or eliminate axle wrap – lest we just keep cracking this thing in two — indefinitely.

What should a fix look like? 

During the next couple of months, I spent time admiring the underside of 100 year old automobiles. And my conclusion was that a torque tube only set-up for dealing with axle wrap, was pretty rare. I found no others in my limited search. Without exception, each car I examined (from 1909 to 1916 or so, had some sort of traction bar, radius rod or anti- torque braces that prevented axle wrap. There were single side braces between the differential housing and the frame. There were single side wishbone or “Y” braces. There were double sided wishbone braces. Some of these devices connected directly to the front side of the differential housing. Others connected from the back plate of the brake drum to the frame. Still others went from the axle tubes near the wheels up to the frame. But the one that seemed best for a simple modification without too much engineering was a radius rod set-up like that on a Model T Ford. Which, by the way, was very familiar to me.

Model T Ford radius rod and rear universal joint set-up in green.

This would be the configuration that I chose to modify and install on our Michigan car. However, this would have to wait while I repaired the damage, which as I’ve shown, was considerable.

The crack in the torque tube was discovered on March 14, 2025. It was significant and total.  The car had made an unusual sort of thumpy noise before I parked it on February 23, 2025. I surmised that the cracked tube and the pressure and flex on to the drive shaft it covers was the reason for the thump. This did not sound like an easy fix.  And….. it wasn’t.

The crack in the torque tube extended all the way around the tube.

So why did the tube break? Well, this calls for some investigation on the purpose of torque tubes and how they have evolved.

The reason for a torque tube is a phenomena called “axle wrap”. Which is not at all like Saran or plastic wrap. It is the twisting force forward or backward of the differential upon acceleration and braking.

This diagram shows axle wrap distorting the leaf spring while accelerating. The red arrows show the twist that occurs during acceleration and braking. The torque tube is supposed to relieve the stress but on early cars, failed to do so.

Our Michigan has what is referred to as a “torque tube drive” set-up. However, its implementation was not well engineered. Indeed, if you examine the close-up photo of the crack, you will observe what appears to be grinding marks adjacent to the crack. That is not my doing, but is an early attempt to repair a torque tube failure in the exact same location.  While trying to figure out what steps to take to fix the problem, I called upon Mike Howard in Kalamazoo. Mike is another owner of a 1912 Michigan and two 1913 Michigans. Mike sent photos of the same area of his 1912 car. It appeared to have been repaired at some time prior to Mike owning the car. The break is in the IDENTICAL  location. It is important to note that the differential and drive train for the 1913 car is vastly different.

Differential & torque tube of Mike Howard’s 1912 Michigan showing repaired torque tube.

Mike Howard’s 1913 Michigan had no torque tube, an additional universal joint and most importantly, big heavy radius rods to prevent axle wrap. – Click on photo to enlarge.

I looked at about 9 or 10 other cars of similar vintage from before 1912 and after 1912. In nearly every case, there was a radius rod setup of some sort to prevent axle wrap. Our rear axle and differential were built by Sheldon Spring & Axle Company.  Most of the axles they produced were for heavy trucks. Our Sheldon “Pleasure Axle” was for cars. https://michiganmotorcar.com/nuts-bolts-2/axles-differential/  It is very apparent that their  model No. 201-D, was poorly engineered and defective from the beginning. Our car, Michigan serial number 3531, and Mike Howard’s car serial number 3477, both have repaired torque tubes. The only other operating 1912 Michigan that I am aware of, #3535, has a completely replaced rear end from a Ford Pinto, complete with hydraulic brakes. This leads me to believe that use of the Sheldon 201-D rear end was short-lived and a continuing problem.

Michigan Serial #3535, completely replaced
Ford Pinto rear end.

So, we know a little about the problem- axle wrap.  And we have some knowledge about how others seem to have avoided it. I really dislike the idea of replacing the entire rear-end with something modern. So, what was the extent of the damage to our car and how do we fix it?