The Stovebolt Site Forums The Parking Lot '60-'66 Trucks 1961 vs 1963 transmission cover

I am going to be replacing the cab on my '63 C-10 with a cab from a '61 C-70. I know that the cab mounts are spaced differently because of the different style frames, but I noticed one other difference between the cabs that I am having a hard time finding information about. The transmission hump is in two pieces on both cabs, a front part that covers the bellhousing, and a rear part that covers the transmission, but on the original cab, the front part is spot welded on, and on the new cab it is bolted on.

I need to replace the front part, and if I knew why they were different it would help me know what to look for. I noticed that there is a cover plate on top of the C-70's bellhousing that my truck doesn't have, so my current theory is that the big truck transmission humps were bolted on to allow access to the bellhousing, and the smaller trucks were spot welded, since they didn't need access.

I would like to get a bolt-on type if that is possible, but if my theory is correct they only put the bolt-on type on big trucks, but my truck has a standard 3-speed, and thus a low transmission hump, and I don't think any big trucks had the low hump. If that is the case, I can cut the spot-welded one off of the '63 cab and weld it on, but that sounds like a major headache. If anyone can confirm or deny my theory, or give me any other information on the subject, I would be very grateful.

Thanks in advance!

I changed the front half of the transmission cover on my '62 C10. I had the low hump for the 3 speed, but a previous owner had installed the 4 speed (SM420). Since it didn't really fit the low hump cover, they just bent up some sheet tin and screwed it on.

Since I wanted to do it right, I located the correct pieces for the high hump cover and cut out the low hump firewall piece. I glued the firewall half in with a spray on rubber undercoating.

I don't know why you couldn't weld in nuts on the engine side of the firewall, and drill matching bolt holes on the firewall cover. Then you could bolt it in like the C70 you got it from. You would probably want to bolt the transmission cover to the firewall piece, the bolt that assembly in to line it all up before you drill for the new bolt holes.

You've got me thinking I may want to do that the next time I have the cab gutted. I haven't done that for a long time, but I will need to do it before I tear down for paint. No telling how long that will be though.

Thanks for the idea!

Cedric,
I also have a cab (66) with high hump that will be on the scrap heap soon. If you need a spare or practice piece you are welcome to it. I dont know anything about the differences in the big truck arrangements but I am interested in what you find out.

Doug, It would be nice to have a spare, I assume yours is spot-welded as well?

Yes. Spot welded. Also looked at my new cab and it is spotwelded. Lots of spotwelds. Should be able to drill those out pretty easily. Easy access and lots of room. I have an extra high hump cover too if you need that as well.

Is that a high hump cover for a 4 speed? I think I need a low hump for my 3-speed column shift. Is this cab from flappy-fenders?

It is from my new cab and does have the opening for floor shifter. I would think the bolt holes would line up but not positive.

Bolt holes will line up. That was the original intent with these trucks. The floor of the cab will accept either high or low hump cover. Main difference was the piece spot welded to the firewall.

63, if you have the 3 speed, either cover will work. Low hump was standard for the 3 speed and Powerglide transmissions. High hump was for the 4 speed, but will not be a problem with the other transmissions.

If you go with the High hump, you will have to specify you have that if ordering carpet or any other floor covering because it does make a difference for that.

I would also think it to be easy step to cover the floor shift opening. I flat plate cover with holes to match the existing holes. If still looking for small hump, we will continue to look with you.

Sorry about the delay, I got busy and forgot to check the thread. I think I would like to hold out for a low hump, for one reason it seems to be much easier to find the low hump carpet, now that I look. Thanks everyone for the advice and support, I really appreciate that you guys put so much effort into helping people out - this has got to be the most supportive forum on the internet!

Try posting in the Truck Parts Wanted section of the Forum.

Not everyone makes it into this section.

I have a high hump out of a 62 gmc 3/4 ton that has the piece that bolts to the firewall and the trans piece is separate. the 60 - 62 gmc that used the Hydramatic trans came equipped that way
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