Just bought a 1956 Chevy 1/2 ton, 3100. The truck has a GM 12 bolt installed, and I need to get the rear wheel cylinders. Unfortunately, I cannot ID the axle from the codes I've found. The stamp on the passenger side front of the tube is TO (maybe k?) and the -0425K-.
I also found the casting number 3896839 on the front of the diff housing, with GM2 also cast onto the housing above this casting number.
From what I can tell thus far the axle appears to be made by McKinnion in Canada. But I have been unable to find a year code anywhere. Can anyone tell me if the K at the end is a year code?
Appreciate any advice or help you folks can offer. thanks in advance.
OK, I decided to take a photo of the axle code. When I enlarged the photo the TO prefix now appears to be a TQ.
According to a chart I just came across in Google, it looks like TQ would make this a 1969 truck axle with a 3.73 gear ratio. That gear ratio seems much closer to the trucks actual performance, than the what is indicated for code TO. Of course, there is nothing to say that the R&P has not been changed at some point over the last 50 years. If someone believes this logic is flawed let me know.
Now at least I can order the wheel cylinders I need to get the rear brakes back online.
Pull the cover off, the ring gear will be stamped with date code and gear ratio, then use that information along with the two digit stamped code to confirm what you have. All GM gears are stamped.
