SM420 Help

Can somebody pls tell me what the difference is between a 2 wheel drive and 4 wheel drive SM420 tansmission? Will the 2 wd version werk in my jeep? What is a divorce transfer case? I did some research on the SM420 and read that it needs a divorce t-case? :? :? :?

And for the topper, pardon my ignorance but wtf is UWOP?

 

UWOP is Useless With Out Pics

the 2wd will have a trailhouseing on it making it longer by a few inches.
divorced t-case is a t-case that has some sort of a coupling to attach the tranny to the t-case without the tranny output shaft going into the t-case. i know that did not come out right so maybe someone could simplify it some. i dont believe a SM420 has to be divorced even if it is a 2wd model. you just need to get an adapter and put in a new output shaft.

 

Hey Jeff thanks allot. I called the guy with the SM420 and he said it has an output yoke instead of a splined shaft. Anyone care to chime in on what he meant? Does a yoke fit over a splined shaft? Please be go easy, the only thing I can do is change my oil.

 

yeah, a divorced tcase means that you have a short driveshaft between the tranny and tcase. that is not something you would want to do for this conversion.

i have never seen a 4wd sm420... i think that most 4wd vehicles that had a sm420 used the divorced setup. what you need is an adapter that matches the tcase you are going to use. it replaces the rear yoke and plate on the tranny with the correct input shaft and bolt pattern needed for your tcase.

novak and AA are the most common sources for the adapters. many people here think that novak is a better quality adapter.

thanks, chris

 

the yoke comes off, and a new special shaft is used. after the yoke and plate come off you attatch the adapter which goes over the old splined shaft on the tranny. the other end is made to match up with the tcase you are going to use.

go to novaks site and look at the pics.

chris

 

Ok, cool. That was my biggest concern was that there may be 2 different 420's. A 2wd and a 4wd model. I have a Dana 18 as my Xcase so I'm thinking it will be fairly straight forward with the adapter. BTW the guy wants $75. I'm gonna go look at it.

 

You Guy's Rock!

 

it is a pretty straightforward swap if you have the $$ for the adapter.
the only mods required are moving the crossmember back a few inches, getting your driveshafts the correct length and either converting to hydrolic or a chain clutch setup.

thanks, chris

 

at that price go for it. the adapter is about $700 IIRC or at least the one for AA was for my t-18a to dana 18.

 

my sm420 was adapted to a rockwell 221 tcase, it was not divorced, it looked exactly like the 465 mounted to the np205.

 

The only thing you need to look for on the sm420 is the tailshaft, make sure that it is a (I think a) 10 spline unit, there is a very rare 32 spline unit, no adapter to fit this unit. I have looked at dozens of 420's now and have yet to see one but supposedly they are out there.