The Stovebolt Site Forums The Shop Area Driveline MY6 transmission info needed please

I'll soon be putting an MY6 transmission into my 68 gmc. It will be replacing a 4 sp muncie. I understand that the input shaft is the same and the length is the same but I don't know if the output shaft is the same; I think the splines may be different. Will I need a different yoke? If so, what do I need and where can I find it? I'd like to have all my parts ready before I get started. Thanks.

Jeff

Jeff, I believe that MY6 tranny is the GM code for the Mopar designed A-833 new process 4 speed with OD. Used in many Dodge/Chrysler vehicles and late model GM pickups. There is a whole chapter devoted to that transfer in the book "THE CLASSIC CHEVY TRUCK HANDBOOK". See link. I'm planning the same swapout, so please let us know how you make out.
https://www.amazon.com/Classic-Chev...eywords=the+classic+chevy+truck+handbook

Thanks Allen. I actually have that book and refer to it often since the Task Force trucks are my favorite. All it says about the slip yoke is that it's 23 spline and used on some other GM applications. I was hoping to find out what those applications are to know where to look for a yoke. I'm going to count the splines on the output shaft of my transmission to verify before buying anything. I've found a few inaccuracies in that book, especially the chapter on the OD transmission, so I don't want to spend any money without verifying that I'm getting the right part. Just yesterday I found someone on CL that's parting out a chevy truck with an MY6 transmission. He has agreed to sell me the slip yoke for $20 so maybe I'll have what I need. If I can find a part number for it I'll post it. Thanks.

Probably the same yoke that was used on many gm transmissions, 3+4 speed muncies, saginaws and 350 turbo automatic trans.

Great Jeff....wait a while to see if anyone has the answer here. If not my tranny guy (Kajun Jon - google him for the number, he has a website) that rebuilds all types of transmissions, with focus on manuals. I've visited with him many times at our local swap meet, and he is very knowledgeable.

Thanks for the info Allen. If the one I ordered from the CL guy doesn't fit I'll give Kajun Jon a try. By the way, I counted the splines last night; 27. Another error in the book. The book says all OD transmissions have aluminum cases and the cast iron cases are 1:1 final drive. It also says all cast iron case transmissions have 18 splines and the aluminum case trannies have 23 splines. My transmission may be an odd ball but it has OD, cast iron case, and 27 splines. These books are great but it always pays to verify before spending $.

Jeff

Jeff, the book is no doubt referring to pre-68 trans, which use a "coarse spline" yoke, as opposed to the later trans [like your 68] that use a "fine spline" yoke [title says 55-60 trucks] .... if the MY6 is pre-68 yu'll need the coarse spline, post-67 you'd need the fine spline, check a wrecking yard, maybe even a FLAPS

Bill

I googled "27 spline yoke" and found some ads for some that say they fit muncie transmissions. Maybe I'll get lucky and the drive shaft I've got will fit right on it. I can always hope.