SM 420 adapter help

I purchased an older used sm 420 to D18 adapter and have a question that I know one of you can answer.
I am not sure what brand adapter it is so I went to the AA and the Novak sites to read their instructions. Novak does not have the instructions online but AA does.
AA says that I need to machine the transmission output shaft for a snap ring or purchase their clamp to keep the output shaft from walking out.
It appears to me that the output shaft is held in very solid and the spud shaft assy will hold anything from walking out.

So my question is, do I need the clamp, ring, or nothing.

Also, the transfer case I want to use is a big hole case. Am I right in assuming that the AA adapter ring is all I need to make the adapter fit my case? And, what is the big snap ring for that comes with the adapter ring?

 

Need photos.

 

Will try to get photos but with my dial-up connection it is a hit and miss project

 

I would call Novak and ask them. I expect they will answer your questions as long as you are specific about what you want and don't take a lot of their time. Worth a try ...

 

Here is a pic (I hope)

 

I've got the Novak adapter but it was too long ago to remember the details.

I'm pretty sure I did not need to machine the tranny output shaft but there may have been a locking ring - sorry I just don't remember. I did talk to Novak on the phone and they were very helpful so I second what Tim said.

On my install I had to drill the bell to bolt it to the sm420 but it wasn't difficult.

GL

 

If the output shaft has a snap ring groove just use a ring that will fit, if it doesn't have a groove you need to use a clamp ring. You can get one from Mcmaster Carr you just need to know the I.D. Use locktite on the bolt when you assemble it.

 

Yup, what sdcj6 said. The snap ring or locking clamp is to keep the output shaft from walking forward. It helps control the clearances in the gears and synchronizer assemblies.

 

I guess I will order the lock collar. It seems a lot simpler than taking the shaft out and having it machined.

Does my adapter look like a Novaks or an Advance Adapters?

 

hard to tell. They've both made minor revisions over the years and both are similar anyway. Usually AA is good about casting in either Advance Adapters or AA in the casting though so If no markings I'd guess a Novak unit.

 

I had my 420 disassembled/rebuilt.
At that time, I had the shaft machined for the snap ring.
I have heard of issues with the clamp ring coming loose, even when loctited.
I have the Novak adapter on mine.

 

If I recall correctly, AA often went with a sealed bearing to support the rear of the spud shaft and Novak did not. Also, I think the length may be slightly different with AA being slightly shorter. Personally, I have the Novak adapter and love it. Good luck.

 

I have an early AA adapter (AA-12) that was set up for a small hole case when I got it. I got the big hole retainer from AA and it worked fine. I don't think there was any provision for a snap ring or collar on the early AA. rather than a one piece, internally splined stub shaft mine uses an internally splined coupler and an externally splined stub shaft. I am under the impression that the stub shaft butts close enough to it to keep that trans shaft in place but I may be dead wrong. I also don't think there's enough room for a clamping collar IIRC, but possibly a snap ring(assuming you have a groove).

 

Mine has a sealed bearing so it may very well be an AA.

I ordered the collar. Quess if it doesn't fit I'll just leave it out. I have no snap ring groove.

 

if you leave the collar out your 420 will probly pop out of high gear