Trans ID for an 1981 c10

[jkhll8]

Any way to tell what trans come originally in the truck? It's a 81 with a straight 6. It's got an auto in it now.

 

[1987 GMC Jimmy]

Check the RPO sticker in the glove compartment. M15 is three on the tree, M20 is four on the floor, and MX1 is a TH350 automatic.

 

[jkhll8]

I forgot to mention I've yet to find the RPO.

 

[1987 GMC Jimmy]

Well, you can check the trans hump. If it's got a hole in it, it came with a standard. If it's solid, it came with a TH350. 700R4 hadn't come out yet.

 

[jkhll8]

It's a 4.1 the more I read the more I'm thinking all 4.1's were 3 on the tree

 

[MikeB]

With a C10, it looks like you could get a 3-speed manual (column shift), 4-speed manual (floor shift), or auto with the 250 six. But on a K10, trans choice depended on rear axle ratio. California trucks were different, as well as C20 trucks.

Checkout the "Power Teams" pages here:

https://www.gmheritagecenter.com/do...its/Chevrolet-Trucks/1981-Chevrolet-Truck.pdf