Asked this question over on XLFORUMS and got a lot of vague answers. I will try here. What other years transmissions will drop right in 1974 cases and roll on without modifications?

 

This book ...

What Fits What on HD Motorcycles
1936 to 1983
Mike Arman nd Kurt Heinrichs
ISBN 0-933078-11-0

... has a brief, but 8 paragraph, detailed technical answer to this question on pages 57, 58. They do not actually list year numbers but they do discuss technical issues. The first sentence is "All trannys interchange but you are safest if you do this as a unit."

My non-expert opinion is that regardless of what trans you try you will have to dismantle, clean, inspect. To get the clearances right will require installing and re-installing at least a few if not many times. It is a job that requires patience. The tech info you will need is in the FSM; the help you will need is from the members of these forums.

One of the issues is that 74 & earlier are right side shift, 75, 76 have the crossover; 77-on are left side shift. There are different gear sets in different year ranges etc.

You would find it useful to buy the book. You should also get the Factory Parts Catalog 99451-78B [and 99451-85A if you would consider trans from 79 to 85]. Then you have more of a knowledge base from which to proceed and ask questions.

 

sporty transmissions have to be shimmed as the machines making the cases are not exact to each other meaning the set distance from side to side is not the same. ( the case halfs ) sooo the counter shaft and main shaft end plays have to be set and in most cases the shift forks will need to be picked ( 6 from zero in each direction are available times 2 ( 1- 2 and 3 - 4 gear changes ) after the end plays are set -

REASON no one can say for sure that one unit will fit another even tho all the parts are the same for the most part even one number different in the chassis number can be different in the shims -- johnjzjz

 

Thanks Gentlemen. I was looking for exactly this information. I can utilize any 1971 to 1976 54a with some work. The shifting fork dial in is new to me. I have the FSM and tools. Might just rebuild mine.

 

chunks missing on the gear dogs is the thing with the sporty and proper fork distance is set with the forks they come zero .005 .010 .020 .030 plus and minus in both directions but do the forks after you have the end plays done not before

in and out with the complete gear box 3 even 4 times is normal