The Stovebolt Site Forums The Shop Area Driveline Torque tube

A friend has a stock 54 GMC with a 4 speed transmission. I have not seen the truck in years otherwise I would not be asking this. He was asking if the 4 speed would have torque tube or open drive. He is concerned that a previous owner had replaced an open drive with a torque tube. Given the amount of work I do not think it was changed.

Can't he just look?

The odds of going from open to TT......hmmmm. Agree with Bill, just look under if the truck is nearby.

Of course he can look and has. It is a torque tube but he had thoughts that it was not correct because the shop manual for the 54 doesn't show a torque tube he tells me.
The truck is currently in storage on his farm in the country.
Thanks

I believe open drivelines didn't start until mid 55.

What size truck is it?
A 1/2 ton or a 3/4 or 1 ton?
Same year will be closed or open depending on model
-s

That is correct for Chevrolet.

Maybe someone will confirm for GMC?

The 3/4 & 1 ton trucks used the torque tube 4 speed that went back to the carrier brg. The rear drive shaft from the drive shaft carrier brg. on back to the rear end was open.

George

I did Tim. Right here.

My 54 9300 has a torque tube 1/2 ton Canadian model

All my 3/4 and 1 tons are open drive from the transmission to the rear, nothing is enclosed, all sm420 transmissions
That’s 1948-1953 years in my collection
OP has a Canadian gmc 1954
But the small 1/2 tons did have tubes for some years I think
That’s why it would be useful to know what specific door tag information in on the truck in question
-s

The likelihood that someone converted an open drive shaft truck to a torque tube setup is extremely remote. The fact that the truck has a torque tube almost certainly means that it cam that way from the factory.

Bill Hanlon's TSB indicates that most trucks in '54 had torque tubes.

Posting the door tag information will enable confirmation of this.

Ooooooooooooops! I missed the possibility that the truck in question may be Canadian.

So to keep the owner from looking underneath to see if he has a torque tube, have him tell us the serial number off the door jamb tag. If it is a US model, I'll stand by the info in the TSB.

Bill, the owner has looked underneath and it does have a torque tube.

The owner seems to think that his truck should have an open driveline and that somebody replaced it with a torque tube. Not likely but who knows what goes on in the Canadian wilderness?

My understanding is that the 1955 Series 1 was the first truck from GM with an open driveshaft. The 54 and 55 series were identical except for that change. The 55 series 1 was produced for approximately three months.