The Stovebolt Site Forums The Shop Area Driveline 54 1/2 ton Rearend Conversion

Is there a swap friendly, open drive shaft rearend that will just bolt onto the original back springs?
If no, what would be the best to search for to replace my dying torque tube assembly?

John

1955-1st series 3100 transmission, drive-shaft, and rear end.

Good luck finding all three parts, and good luck finding the rear end that has more life in it than yours.

For about $800, you could put new 3.55 ring and pinion gears in your 54 rear end, and have all new bearings, bushings, and seals.

I put a 55.1 rear pumpkin in mine... with a two-piece driveshaft and a SM420 tranny

GMJager,

Was the original drive-shaft two-piece?

Is there an advantage/disadvantage to 1-piece vs 2-piece in this application (3100 1954)? A friend of mine will be doing this in the future.

I believe that the original was a two-piece drive shaft. The first section goes just underneath the cab and 2 feet (estimate), to a bracket there, hanging by this . My truck didn't originally have a two-piece shaft (Torque Tube), so I used a Universal transmission crossmember and made it fit.

As far as advantage/disadvantage... don't ask me... I'm not a driveline guy. I DO know that trucks are still made with two-piece AND one-piece today.

I have never seen the drive-line on a 1955-1st series 3100, but I think there was one propeller shaft (drive shaft).

Here is a page from the Specifications Manual.

What rear-end are you using?
Is it a 55-1st 3100 rear end?
If not, how did you arrange/mount the springs?

Did you obtain the drive-shafts and rear-end as an assembly (with rear springs)?

Sorry about all the questions.

I know the rear-end (pumpkin and axle housing) is from a 55.1 with 3.90 gears. It fit perfectly with the stock springs w/o modification (other than drilling the spring perches to center up the wheels with the fender).

The drive shaft MAY be from something else, but it fits perfectly. I swear somewhere I saw a stock two-piece on one of our 1/2 tons... but I can't find it anywhere.

I got them from a buddy who's truck was restored back in the 70's. He took everything out and went the V8-700r route, and I took his old parts.


no worries about the questions, I'll answer any to the Best of my ability

Hi John, You've seen my 54 GMC 9300. I used a rear end out of a '67 Chevy half ton with 3:73 gears. Cut all the coil spring stuff off, went to a trailer place for some pads that fit the axle tubes, centered it and set the pinion angle then welded it. The only real problem was getting the E-brake cables hooked up. You will have to move your center bolt holes on the pads to get them to center on the springs. If you want pictures I'll gladly email them to you.

A '55.1 half ton driveshaft is one piece.

Thanks guys. Sounds like bearings to me when I was driving, but there's not much noise now its on jack stands.
I'll try the axel bearings, easy enough but looking for that "plan B". If i'm rebuilding a rearend I might as well go T-5 and an open drive line.
If I go open, I'll take you up on the photos Warner.

I know its not truck but i mounted about a 76 nova rear end under mine, 52 3100 and it bolted right up as far as width and spring pad location goes. Only thing you might not like is the original springs are skinnier than the spring perch on the axel housing is, leaving about a half inch on each side. I also removed the shortest spring to fit the thickness. So far everything seems to be ok and have talked to alot of people at shows who have done the same thing.

Joe

I know its not truck but i mounted about a 76 nova rear end under mine, 52 3100 and it bolted right up as far as width and spring pad location goes. Only thing you might not like is the original springs are skinnier than the spring perch on the axel housing is, leaving about a half inch on each side. I also removed the shortest spring to fit the thickness. So far everything seems to be ok and have talked to alot of people at shows who have done the same thing.

Joe