The Stovebolt Site Forums The Shop Area General Truck Talk transmission ID

How can I determine what kind of transmission I have. It's on a 1954 inline 235cc full pressure engine. I saw on different threads mentioning "T5". It almost sounds like the "T5" is a standard tranny for these old girls. I've never worked on trannys before and not sure if I will on this one. Rather leave to someone who knows what there're doing. Has anyone rebuilt one of these before? If so, how difficult is it and are the parts available? My mechanical knowledge is pretty sound and I'm sure I can do it, just wish I had done it before!

Thanks for any input,

~Ron

mummdogg,

I enclosed a link that will show just about any transmission you might have. The new, modern T5 shown does not have its tailshaft on...it would be quite a bit longer.

The standard heavy duty transmission for the rig you noted would have been the SM420. It is a 'top loader'...the shifter is on the floor.

I don't think a three speed transmission is shown on the link. It would of course be your 'three speed on the column'. I hope this is helpful.

http://www.novak-adapt.com/knowledge/transmission_gateway.htm

Stuart

If you are refering to the 6400 in photo,s it more than likely is the SM420 4 speed with granny low. They are easy to rebuild. Get a good manual & follow directions. The bearings , gaskets & seals are readily available but if you need any hard parts you will probably have to find used ones or get another one for parts. The T-5 you see mentioned is a 5 speed used in s10 pickups & other vehicles. A lot of us are putting them in the light duty trucks to get the o-drive feature. It would not stand up in a heavy duty truck.

I had a 49 3/4 ton once that had later 235 in it with a Clark 5speed behind it. Sure wish I'd kept that truck. I gave the darn thing away.

Thanks guys for the info. That's exactly what I wanted to hear. Stuart, the link you attached is awesome. I already put it in my "truck" folder. Very useful. I also did a Google image search for "SM420 4 speed transmision" and it showed where I can get the casting number. When I locate mine, can you guys check to see exactly which kind I have for me or is there a website simillar to "Inliners" I could check myself? On the link Stuart attached, the SM420 is the only transmission available for the 2-tons in 1953. Is that correct or are their others. The SM465 and the NP435 look simillar but were available in later model trucks.

BTW, the pictures on the link show the SM420(135 lbs) is a monster of a tranny compared to the T5(60-70lbs)!

Thanks alot,
~Ron

I'm in the process of rebuilding an SM420. There are rebuild kits available that include all the bearings, seal(s), gaskets, synchronizer rings and misc. small parts. You need a variety of special tools, but the work is not difficult.

Polarcat,
On that SM420 tranny you're rebuilding, does the speedo drive gear run off the the main shaft? What vehicle are you going to put this tranny in? Thanx.

ShovelheadDon1200cc,

In a way it runs off the main shaft. The gear engages in a worm on the U-joint flange, which of course sits on the main shaft.

The tranny is now in my 1952 GMC 1 ton, and it runs beautifully.