Things I learned the hard way about installing an sm420 (so you don't have to)

During the course of installing an sm420 in my '69 CJ5, I learned a few things the hard way. I'm documenting this so others can learn from my mistakes.


1. Most of you probably know this but there is a right and wrong way to install a GM throwout bearing.

WRONG WAY:


RIGHT WAY:


When I pulled my T14, I carefully photographed the throwout bearing and clutch fork:



based on the above photograph, I went ahead and installed my throwout bearing in the clutch fork the WRONG way. Only after TomTom and I had installed the sm420 did I realize that there was a RIGHT and WRONG way to do it.

Here's a YouTube video link showing the correct way to install it:

http://www.youtube.com/watch?v=e4e8P0fFltk

Last night we pulled the transmission and installed the throwout bearing the RIGHT way:





2. If you are test fitting the spud shaft for the Novak adapter on the back of the sm420, be VERY careful you don't pull the sm420's main shaft out. I was doing a test fit of the spud shaft and went to pull it off. The main shaft came out about 1/4-1/2 an inch and I screamed like a little girl when I realized what had happened. I was able to carefully put it back in, but I just about had to change my shorts.


3. If your transfer case has advance adapters intermediate gear kit:

http://www.advanceadapters.com/products/dana-18-intermediate-gear-kit-716005--716006/

the castle nut on the intermediate gear shaft may interfere with the Novak adapter:







We had to grind a little bit of the adapter for the castle nut to clear.



We decided to put it back in as one piece:









Now we are on to the crossmember issues.


I hope I don't have to add anything more to this thread.

 

Going to retain the stock skid for now.

 

gees I could write a book, but don't want to hijack
check the disc on the input splines
oops...too late

 

Is that a theory, or did you confirm that was the issue?

 

99% theory that will be 100% confirmed

 

I'd be very interested in the measurement from the face of the transmission to the face of the clutch plate when the plate is pushed toward the splines as far as it will go.

 

Feel your pain, bro.
Wait until you go to fit your front drive shaft.

 

You cats are skeerin' me. Am I goin' t want to sell the parts I've gathered for this conversion by the time this thread is through?

 

Don't be scared. Just be aware of the mistakes you can make. Don't make these mistakes, make new ones.
R)

 

Chin up. The end result is so worth it.

 

My business partner just had an issue with the splines on the clutch disc with a SM420. I wasn't there to help him, but apparently they were bottoming out on the input shaft splines and causing it to not release. He resolved it by re-using his old disc as the parts guy couldn't find anything else to offer.

 

Here's a thread describing that issue:

http://earlycj5.com/forums/showthread.php?t=79659&highlight=sm420+splines

and