Inherited Grandpa's 78 C20 - SM465 help needed!

[Gijordan07]

Hello everyone! I just inherited my Grandpa's 1978 C20 long bed, which I'd really like to get running for my Mom asap, and restore over time with my boys. Purely sentimental reasons, which are the worst because there are better specimens out there... but anyway

He had just put a new engine in it when 3rd gear went out. He did what lots of old farmers sometimes do... pulled the trans and put in one from his other old squarebody. Same thing, trans no good. So he got pissed, put the parts in an old hub cap in the barn, the cases in the shed, and got another truck. 25-30 years later never did get around to fixing the trans.

Problem 1: I've got a working and shifting SM465, but turns out it was a 4wd so the rear is different where it should mount to the crossmember. I've got a dead 2wd but it's missing the rear extension piece, and I've got another sm465 empty case with a bucket of pieces, but no rear piece either

Problem 2: I've got NO cross member, no bolts, no idea what I need to reinstall a trans. Found an Ebay listing for new crossmember, but still no way to mount the trans because of the rear cover difference. Also, what size bolts mount the crossmember to the frame?

Problem 3: found a driveshaft in the barn, no idea if it's the right one. How long should it be? Is it 1 piece or 2 piece with a mid bearing for a long bed?

Sorry it was so long winded, and thanks in advance for any advice you all have!!

 

[Shorty81]

Welcome from Ohio

 

[Grit dog]

My go to is start searching Craigslist and FB.
And here of course.

Nice part about these trucks is, aside from maybe some obscure trim piece, virtually every part for these trucks is still available new or used and fairly plentiful.

If you really think it may be driven a lot and restored, you have the perfect opportunity to install a 5 speed so that you have OD. Or an old A833 4 speed with OD, but I think those are pretty rare and more of them are Mopar bellhousings.

 

[Rusty Nail]

Gonna need pix dude...they upload from your phone real easy.

 

[SDJunkMan]

Welcome from South Dakota. Too bad you are so far away, I have a spare 465 for a 4 wheel drive that I don't have plans for.

 

[Gijordan07]

Awfully kind of ya SDJunkMan! One of my problems though is that the truck was a 2wd, and I'd like to keep it that way because it's in rough enough shape I don't want to start swapping differentials etc. at the moment

I have a confirmed good SM465, but it came out of a 4wd, and what I've been told is that it won't mount to the crossmember (that I dont have) because the 2wd version has a rear cover with "pads" cast on it for the mount bolts that the 4wd rear cover does not.

The two dead SM465s from Grandpa's shed were both in various stages of disassembly, and no rear covers to be found anywhere.

So I'm curious if anyone knows if there are additional differences in the 4wd SM465, or if it's just a rear cover I can swap (whenever the heck I find one). I'd think the output shafts are different too, but I've been told mixed things.

Lastly, can I use the 4wd trans, as is, no Tcase, and just weld some mounting pads on the back of it for use with the ebay crossmember?

 

[SDJunkMan]

Awfully kind of ya SDJunkMan! One of my problems though is that the truck was a 2wd, and I'd like to keep it that way because it's in rough enough shape I don't want to start swapping differentials etc. at the moment

I have a confirmed good SM465, but it came out of a 4wd, and what I've been told is that it won't mount to the crossmember (that I dont have) because the 2wd version has a rear cover with "pads" cast on it for the mount bolts that the 4wd rear cover does not.

The two dead SM465s from Grandpa's shed were both in various stages of disassembly, and no rear covers to be found anywhere.

So I'm curious if anyone knows if there are additional differences in the 4wd SM465, or if it's just a rear cover I can swap (whenever the heck I find one). I'd think the output shafts are different too, but I've been told mixed things.

Lastly, can I use the 4wd trans, as is, no Tcase, and just weld some mounting pads on the back of it for use with the ebay crossmember?

Oops, I thought you needed a 4 wheel and had a 2 wheel, not the other way around. Can't help on the differences, but I am pretty sure someone here will know.

 

[bucket]

Where at in Michigan? I've got a nice 2wd SM465 that I would happily swap for a 4x4 version. Or I could sell it outright if you would rather not swap.

The biggest difference is the output shaft, BTW. The 2wd unit has its own style output with a yoke that mounts to it.

 

[Gijordan07]

I'm in Kalamazoo, how about you? Also, any idea on the driveshaft style and length?

 

[bucket]

I'm in Ohio, a little ways southwest of Columbus.

I'm not positive on the driveshaft style, but it should be the 2-peice type with a center carrier bearing. I think.

 

[PrairieDrifter]

I'm in Ohio, a little ways southwest of Columbus.

I'm not positive on the driveshaft style, but it should be the 2-peice type with a center carrier bearing. I think.

Pretty sure the sm465 2wd would only accept the two piece driveshaft.

 

[Wumbo]

My long bed sm465 truck has a 2 piece drive shaft.

 

[pduffyd]

Hi Gijordan07

For parts try here and a history on the SM465.

https://www.novak-adapt.com/catalog/transmission/transmission-parts/sm465-parts

I bought the felpro gasket set as they are thicker and better quality.

A damn good way to rebuild a 465 is here.

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.

And yes the long wheel base 131.5" C20 is a 2 piece drive shaft. Well mine is anyway.

 

[pduffyd]

Oh forgot to add this link on differences between 4wd and 2wd 465 versions.

https://www.novak-adapt.com/knowledge/transmissions/manual/sm465/