1970 C20 Manual Transmision Identification Help.

[DEESTER157]

Hey all, I just purchased a 1970 C20. The previous owner was in the process of converting it to an automatic. It is a factory manual truck. I got the original transmision with the truck but I was trying to determine if this is the original transmision or even the correct one as I am trying to go back with the original manual transmission. It is a 4 speed and the only number I have gotten off of it so far is on the passenger side of the case. This number is C 96041W. Haven’t been able to determine what this is. Are there more codes or numbers in other places? Any help with this would be greatly appreciated. Thanks

[B. W.]

Welcome to the forum, post a pic, should be a 465.

[geezer#99]

A couple pics will identify it.

[DEESTER157]

Thank you. Ok, I will try and post some pics when I get home this evening. Do the numbers seem right for a Chevy trans? Thanks

[DEESTER157]

sry just testing to see if I could upload a pic. It worked so I will upload a few pics of the trans this evening.

[geezer#99]

What else did he do or remove for the swap?
You might want to post some more pics.
Like the back of the motor, tranny tunnel, crossmember etc.

[DEESTER157]

Well he put in a 700r4. So I’m not too sure on what he did to the crossmember to mount it. Not too sure on what the original looks like for a manual 4 speed. He did give me the Bellhousing also and I was able to look up those numbers and found that atleast it is original to the truck. The clutch pedal and everything is still in the truck as he never finished the complete swap. Number on bellhousing is 3925505. So ya I’m also a little confused on what I need to do to mount the Bellhousing and original transmision.

[DEESTER157]

I will also post pics of the setup under the truck as it sits now. Maybe someone that knows what their looking at can give me direction on what I’ve got and what to do!

[geezer#99]

Reason I asked is the bell housing bolts to the crossmember and the crossmember is riveted into place on the frame.
When people swap to an automatic they usually need to remove the crossmember.
Take lots of pics.
Everybody will jump in and help you out!

And welcome to the jungle!

[DEESTER157]

Ya I will take lots of pics! I was thinking that the original crossmember is prob not there. And I’m assuming that even if the crossmember was takin out and replaced for the 700r4 swap, this can be put back to original? ( if I have the right 4speed tranny).I sure appreciate all the help on this journey to restore this truck! Yes sir, glad I joined! Thank you

[DEESTER157]

I do know that when I put the Bellhousing up to the transmision, the two top horizontal holes lined up but the two horizontal holes on bottom did not. Does this seem normal? And my Bellhousing has two flat spots with a little horn on both sides with vertical holes so it seems to make sense that this is where you would mount the bottom of the Bellhousing to the crossmember. Using the two top horizontal holes and the two vertical holes through the flat spot on the bottom of Bellhousing.

[DEESTER157]

[DEESTER157]

[DEESTER157]

[DEESTER157]

[geezer#99]

Appears to be a Muncie sm465.

[DEESTER157]

Well when I look up a Muncie Sm465 or SM420 they look different. And I can’t match up the numbers on this transmision to anything. The muncies have different numbers and I can’t find GM anywhere on it.

[geezer#99]

Might be some better info here.
Likely I’m wrong and it’s a 420. I can’t remember what year the change was.

https://www.novak-adapt.com/knowledg.../manual/sm420/

[kwmech]

I think it's an NP435 and it is not out of the chevy truck judging by the input shaft. Looks like it is out of a dodge looking at the rear output yoke

[geezer#99]

I think you’re right kw!

https://www.novak-adapt.com/knowledg.../manual/np435/

My apologies to the new guy!

[DEESTER157]

Sry got busy there for a bit. Ya i did some more research and thats what i came up with. Its def an NP435. What makes it not a chevy? Still confused about that. Will have to do some more research. I know it does have the 10 spline input shaft. What else would i have to check to verify what it came out of? Thanks for the help!

[geezer#99]

Does it bolt up to your bellhousing?
And does the input bearing retainer fit snug in the bearing retainer hole in the bell?
You got more pics?

[DEESTER157]

The top two holes line up but the bottom does not. And i think it was a good fit on the bearing retainer. Ill have to put them both together and take a pic. Any certain pics i should send? Thanks

[geezer#99]

Your crossmember if it’s there.
Back of the motor.
And the shifter location in the hump.

Is this a high hump truck? Hump is taller for a 4 speed and bolts in.

[DEESTER157]

Ok, if it’s not too late when I get back home tonight I’ll take a few. Haven’t looked at the crossmember or the hump to be honest. If it’s too late then I’ll take them tomorrow and post if that’s ok? Thanks