The Stovebolt Site Forums The Shop Area Engine Shop Was an 3spd OD available for torque tube rears?

I'm really not up on the earlier trucks, but I thought I read here that the trucks had a torque tube sometime before '55?

Am I right in that, or no?

And if they DID have a torque tube, were they every available with the 3spd OD trans?

Thanks,
-Brad

The torque tube ran to '54, trucks bult after '55 were open driveline. There was no overdrive option on the torque tube trucks, open driveline only.

Truckstell built an OD by altering the enclosed driveshaft without even touching the transmission. I was lucky enough to see one once and I doubt Ill ever see another.

Jeff

The Truckstell units were a dealer or custom shop installed option that went in the torque tube as Jeff said - meant for cars only from about 41 to 54. I have read of them being installed in a few 1/2-ton pickups and suburbans. Rarely one pops up on ebay. I have imagined installing one in the front torque tube of my 3/4-ton pickup. Dunno...

Here are a few pictures of one
one
two
three

....isn't the StoveBolt amazing. This is THE place for knowledge.
I learn new stuff all the time.

Aint that just Nifty!

Frank50, Installing a regular Chev overdrive with a Borg Warner overdrive back section isn't very difficult in a 3/4 ton because your 3rd member has an open drive shaft. Having an open drive shaft built from the transmission to the center bearing is not that expensive. The Borg Warner unit was .70 OD. That works out real well with the 4.56 rears. Of course more horse power helps with od, something like a GMC 270 or 302.

I thought the 3/4 tons had a short front driveshaft that was enclosed on the transmission end and open on the rear? Maybe Im thinking of the wrong year.

Brad - back to your original question: Chevy & GMC 1/2-tons had torque-tube drive to 54, just like the cars.
On 3/4-tons the front section of drive shaft is torque-tube - to the carrier bearing - then open behind that - thru 53 at least. I'm not sure about 54 but I know by 55.1 it was open all the way. (I had one.) I wish I knew more about B-W and other OD options. .70 x 4.57 = 3.20. Not bad! I want to keep a steep low gear like my SM-420 but with OD...

This is a pretty good discussion of the overdrives that GM used with a Borg Warner overdrive unit behind them. http://www.hydratech.com/pctc/Public_Documents/bwrebuild.pdf

Just re-visiting some older threads: I guess this has been discussed to death, maybe - but is there anyway to mount the B-W overdrive unit found on Chevy 3-speeds to the back of a SM-420?? I know it has been done with 4-speed car transmissions.
Any way to mount any overdrive to a SM-420? I know there are adapters/kits to mount 4x4 T-cases... Just trying to brain storm someway to get an O/D with my SM-420.

Borg Warner overdrives were never built to mate to a SM420. If you have a 3/4 ton, you will have 4.56 rears with an open drive shaft at the rear. Why not find a 55 or later Chev 3 speed with an open drive shaft already on it The 4.56 will be very drivable with the .70 OD and the only thing you will have to modify is the drive shaft which is quite simple.

Thanks Ken. I know that a 3-speed was standard equipment on a 50 3/4-ton; mine happens to have a 4-speed. I really love that low 1st gear, though really to date I have not needed it for anything. The first AD 3/4-ton I had 20 years ago was a 55.1 with a 3-speed and 1-piece open drive shaft. The 3-speed/OD is a viable option.

NV4500 swap! Find an Nv4500 out of a 1994-1997 dodge 2wd truck. Get an adapter plate from Advanced Adapters (Note the adapter will need further machining to fit your bellhousing). Turn down the snout of the bearing retainer on a lathe to match the diameter of your exhisting bearing retainer. This allows you to use your stock throwout bearing. Or talk to Advanced Adapters as they will have a crossover bearing to work with your fork. Bolt adapter to bellhousing and transmission to adapter. Cut new hole in raised floor section approximately 6 inches back from existing hole. Have driveshaft shortened or new shaft made. Drive around with a smile on your face with a 5 speed fully syncromeshed transmission that has a granny low gear (5.61:1) and an OD gear (0.73:1)

Of course this is an oversimplified version of the swap. Do a search for more details. Of course I wouldn't reccomend an OD in a 3/4 ton with a splash 216 or 235. A full pressure 235 or 261 would have my blessing.

The New Venture is a good way to get an overdrive and still have a good low hole. It is doable where I would say putting putting an OD in a SM420 is impossible from a practical standpoint. However if you have a 50 model with the original engine, I would agree with John. I think you will be too underpowered to pull any kind of OD.

Rusted,
You are correct that a 3/4 ton had a closed drive shaft to the center bearing and open from there to the third member. However, that doesn't mean you can't use an open drive shaft all the way from the transmission to the rear end.

Thanks for the comments!

Yes, in fact I contributed to that thread. I have been interested in the Truckstell since I first learned of them a few years ago. I have thought of trying to install one in the front torque-tube half of my drive shaft, but I really need one to figure out if it will work or not. I would only be interested in any O/D for straight, level highway cruising with a light load.... The truck will go 55 now without a strain.
Thanks.

Frank, Looked at all the options for years and because I have a PTO attached to my sm420 I was pretty much wed to it. So, opted for a gearvendors. There is an adapter that bolts to the sm420 followed by the gv unit, followed by drive shaft shortening. Works very well but let me tell you. GV doesn't give anything away. I actually drove the 100 miles to their factory and spoke with a rep. They were not bashful about taking my money. There is a 5 speed that is a direct replacement for the sm420 that they had in their showroom. Can't recall the #. Don't know the price. Probably nose bleed territory as well >(