Originally Posted by tclederman
msmalley,

Welcome to Stovebolt.com
You might want to also check out oldGMCtrucks.com
That year GMC engine and dash/gauges are different from a Chevrolet truck.
Brakes and most front end parts would most likely be the same.

Most likely you have a 100 series - 1/2 ton?
A Maintenance Manual should be available from parts vendors.
Here is an early 1955 manual with info on the H-M transmission.

You might as well drain the transmission and put in the correct fluid.
I do not recall if there is a transmission filter (members here should know).
That is a complicated transmission, if it needs repair.
The good news is that it is a good/strong transmission - it might need repairs.

Look here in the Tech Tips for advice on checking out a new truck.

In the Tech Tips, look at the 3.55 Ring & Pinion conversion (for a 3.55 ratio, instead of the 3.90 ratio).
You would need to obtain a 1948-1953 ring-gear carrier (GMC or Chevrolet 1/2 ton).

Tim,

Thank you very much for all of the advice. Yes this is a 100 Series 1/2 ton, and I will check on the manuals. I have visited the OldGMCTrucks site, it was actually the first site I found in my search. I tried to join but I never received a confirmation email from them so I think that the site isn't active. I have gone thru the site and downloaded all the information that I thought was relevant to my truck. I am surprised at the lack of information available for older GMC's on the web. I will repost my drive train questions on the correct forum, but it sounds like it would be worth sticking with the original kit. I just didn't want to go through all of the time and work to keep it if it wasn't going to add any value.


1954 GMC Series 1
102-24 Series 1/2 Ton Long Bed
248 to a Hydramatic