The Stovebolt Site Forums The Shop Area Driveline T10 or A833???

I am building a push truck for the local speedway. It's a 150 Series 1941 GMC that for now is bone stock. I am replacing the 228 with a 302 and would like to change the tranny to an updated 4 speed that I can keep a low gear in as My commander in Chief wants me to put a dual rearend under it.
With a 302 built for torque, which is more appropriate? T10 or A833??? The one ton rear end will need new ring and pinion, but what size? Should I stay with the stock gears or change to something taller? I'm worried about the health of the drive train more than the motor, but once I have the gearing figured out I can set up the block to give me the torque I need without being abusive to the drive train.
I like to keep things simple, less is more IMHO.
Thanks....

Humble Newby

The granny-low 4 speed has the lowest 1st gear ratio of any single range transmission. Ever. 7.20:1 if I'm not mistaken. Tied to any rear end you're going to have a crawler. My 49 has one and a 4.56:1 rear. At full wind out (2800rpm) it's doing about 8-10mph. The 4speed box will take plenty of torque. I think it is an SM420, but I'm terrible with names.
Find a 1 ton dually rear and it may have a 5.14 gearset. Great for pushing, but you might take 3 days to go from your house to your local track...

Neither transmission is suitable for the use you're looking at. A better choice would be the SM420 or SM465 4 speeds, which are rated for the use intended.
For the rearend, without knowing what rear you pan to use (Corp. 14 bolt? Dana 70? Eaton HO72?) and what tire size your'e going to run, it's somwhat difficult to pin an exact ratio. For use as a push truck, you won't want a taller gear, but rather a short gear for more grunt. I would say no higher than a 4.10, preferaby a 4.56 ot 5.13 (both stock gearing in the HO72).

Longbox, Not sure I'm willing to go along with the A833 not being rated for the job. Dodge used it in trucks up to the 3500. The questions I have are 1. Will the A833 first gear (3.09) be low enough. 2. How much highway driving will the push truck get too make the OD necessary. If no highway driving then the 420 or 465 win.

Larry

Wow.... Lot's of things to consider here, all great information. I am building the 302 for max rpm of 6000. (a bit of a hot rod). Pops felt that the Borg T-10 would be more than suitable and I thought the A833 would be better suited for the size of rearend that I am using. I agree that finding out the gear ration in the new rearend is crucial. My bad I should have noted that it is a 5.14-1 rear end out of a '44 GMC 1 ton. I will swap out the Budd's for something newer. Perhaps a 70's C30 set of rims and tires. I'm hoping the C-30 front end will work too. The push truck is an ad piece and will do very little if any highway miles. The track is about 5 miles from the shop. Modifieds and Sprints as you know need a brisk push to get going. I'm not sure 8-10 mph will be fast enough. What other options do I have??? I will start looking for 420 and 465's upon Larry's reccomendation. Thanks guys... so much food for thought. I appreciate this so much.

Humble Newby

Oh yeah.... better do some before pic's.... I'm tearing her down starting today...

http://s1185.photobucket.com/albums/z358/speakfordadead/

Beauty truck!
Figure out the speed range you want for pushing, what diameter tires you will run and gather a bunch of gear ratios from the transmissions you want to run. Then hit one of the speed calculators available on the web. There are many and are easy to use (especially on some of the 4x4 sites). Start plugging in numbers and you will find the ratios you want.
Ref the SM420: I top out at 8-10 mph because I won't run my 60 year old 216 splash oiler over 2800 rpm. At 6000 rpm you would be roaring up to 20 mph! Speed Demon! LOL!

What about a Hydramatic??? would that solve my problem? Don't want to shift gears while I'm getting these rigs off to a start.
What say you oh great guru's????

It looks like Pops has lot's of Hydramatics in the Tranny Container. I'm liking the SM465 (it looks new... in cosmo) but the bottom line is like Highflyer said, it's all about the calc's. With the 5.14:1 rearend and the 3.09 low gear at 4500rpm I'm in the neighborhood of 17-18 mph. First gear gets me closer. Thank goodness the cars I will be pushing are light. Got my Fab guy coming over Monday afternoon to measure and pick up the rear fenders. The block came out of the hot tank this morning and passed Mag. Yippee... I'm rolling now!! Thanks so much you guys... This Crash box thread is perfect for newbies like me!!!!

Thanks again....
Humble newby

Check out these tranny pic's
http://s1185.photobucket.com/albums/z358/speakfordadead/

Every 2500 or 3500 Dodge I've ever driven either had a New Process 4 speed or an NV 4500, never seen one with A833, which is a passenger car based trans. The 420 is a direct bolt in with the '48 and later bellhousing, the 465 will require some machine work, but will fit.
If you go automatic, TH400 is the best choice, unless you can come across the TH475 from a motorhome.

Towards the bottom of this web page is a list of where this trans was used;

http://www.drivetrain.com/parts_cat..._kits/a833_new_process_overhaul_kit.html

Larry

Must have been a base trans for the bigger trucks. I've only ever seen them in 1/2 tons. The bigger trucks got the 433 and 435s from New Process, which are similar to the SM420.

Okay.... I see where this is going. (Ya'll are hijackin my thread!!! jk)
I found an SM465 and by machining I assuming the bell housing center hole needs to be bored out. I tried fitting a bell housing up to it from a 302 and the center hole is a 1/4 or more too small. The bolt pattern however measures out to be the same. Check my new pic's as I have posted pic's of the tranny and Differential. Can anyone tell me what (other than corporate) rear end it is? Thanks guys, this discussion has been incredible.... you all ROCK!

That's an OLD Studebaker truck rear end- - - -early 1950's or older. The dual wheels make it at least a 1-ton capacity.
Jerry

Thanks Jerry!!
The dimensions are identical to the 3/4 ton gmc. I was hoping it would work as an upgrade for pops truck. I honestly didnt know Stude made big trucks.

Humble Newby

Check out the Studebaker 1-tons from the middle 1940's, civilian and military. That banjo-type housing resembles a 3/4 ton Ford a little, the one that's the base unit for the Frankland quick change, but Stude had that distinctive stepped shape to the housing. Studebaker actually started out in the covered wagon business back in the mid-1800's. They built a lot of the wagons that took the pioneers west over the various trails to Oklahoma, California, etc. The old saying about Studebaker was "They ruined it when they took the wagon tongue out and put an engine in!" Pretty rugged trucks, actually, and the toughest of the WW II military rigs, even better than GM and Ford according to the guys who drove them.
Jerry

awesome trucks.... thanks for the history lesson....

Humble newby