SM420 on early CJ / Dana 18 and Dana 30 frontend--

I heard that a Dana 30 drive shaft yoke on a Dana 18 T-case front drive will not clear the side of an SM420 (if converted) That is-- the SM420 is so wide that a front Dana 20 T-Case yoke ( adapted to the original Dana eighteen) will not have enough clearance to turn- ( because it bumps the side of the SM420).

Anyone have experience or can verify this situation.

This means a hybrid front drive shaft with a Dana 25/27 yoke on the D18 t-case end and a Dana 30 yoke to the diff end.

I am wondering cuz I am about to build a front driveshaft with future plans for a SM420 swap.

 

the ujoints are the same size, regardless of the yoke you use. The dust seal on the yoke might be larger????
There is the smaller diameter V6 yoke and ujoint you could use on the t/case end.
other than what I've mentioned, I have no experience in the swap to offer.
just a parts perspective

 

http://www.novak-adapt.com/catalog/kit_422.htm

Some good info there. I have heard of some people having to grind some of the ribbing away for clearance but the yoke itself should be far enough back not to be too much of an issue. Are you having issues or is this something you have heard of? Like Jpflat2a said the yokes are the same size with the exception of the small V-6 yoked driveline. Novak's site says with their adapter an even larger yoke may be able to be used..... Nickmil

 

Thanks--

It appears that yoke size is not an issue with Novak..

 

My business partner used a Novak kit to install a SM420 in his 1970 Renegade V6 with no real clearance issues. We got a D20 output yoke from J&W for the D18 so both ends of the front driveshaft are the same.

 

Is the Novak adapter longer than the Advance Adapters one?
I used the AA adapter and had to grind on the transmission housing to clear the front output yoke.
I wasn’t too worried about grinding on it, the SM420 uses a really thick cast housing.

 

Novak's is listed at 4.4" long. AA offers two, one a spud shaft style at 4.0" and one a main shaft style at 4.5". That seems backwards to me but that's what their web site lists. Nickmil

 

I saw that some time back and wondered if they didn't do that to keep out of the ribs a little better?

 

I used the AA kit 5 years ago, the spud shaft style (4")and a small V6 yoke, broke the Ujoint (that thing is small!) 6 months later when the front end hopped in the snow. I then ground the case to get a normal 1310 series Ujoint in and have not had a problem.

Having used the AA kit once I would probably try the Novak kit next time just to see if the 1310 yoke clears. Not that there was anything wrong with the AA kit at all.

Of course I would probably go with a 465 and not have the clearance problems at all since they do not have a case bump to clear the reverse gear like a 420 does on the pass side.

 

Jumping in a little late here. I have an AA SM420 to D18 kit. The front output yoke hits on the transmission case. It should turn just fine with some minimal grinding (which I haven't done yet) to the transmission case.

 

Both the sm420 and sm465 have clearance issues with the transfercase. The sm420 is far worse, when I put the 1" plate adapter for the sm465 on Coby's setup I still had to grind the ribs on the transmission case, but it was to clear the twin stick housing, the u-joint is not a problem. The u-joints will clear the sm420 with the Novak adapter but just barely, about 1/16", firefighter mike ground the ribs on his case to give more clearance on the large yoke.

 

I just put a Dana 30 front end on my jeep. I kept the 1310 series u-joint on the differential and the smaller u-joint on the transfercase, which required me to make a new driveline. I have the sm420 with the Novak adapter. My late model sm420 has the reinforcement ribs on the passenger side of the case (I have an earlier spare sm420 without the ribs). Because I had to put the slip joint of the driveline at the transfercase, I had clearance problems between the Zerk fitting on the slip yoke and the center reinforcement rib. I ended clearancing the rib with a grinder to clear the Zerk and to just provide more clearance between the slip yoke and the transmission housing for those times the frame gets crossed-up. While I was there, I held up a 1310 series yoke and there looked to be enough clearance. I will eventually replace the small yoke on the transfercase so I can run 1310 series u-joints everywhere. I just maintained the smaller yoke because those were the parts I had available. I could provide photos if you would like.

 

I'm in the same spot as jeep67 (Novak, sm420, zerk, small u-joint). I'm not in a big rush to replace the small u-joint because it hasn't given me any trouble and because I'd rather replace a u-joint instead of a ring and pinion. I do have to carry two sizes of u-joints on the trail.