Ok, Not sure if I'm posting this in the right place, If not bear with me, new to the site.

Here's the deal, The Auto Transmission just died in my 1998 1500 4x4, No way its going to be a simple fix, bottom line a new trans will have to go in, BUT.....I was wondering, Several people I know have had nothing but trouble with the automatics in these trucks, What would be involved in swapping in a 727 out of a older truck??? Aside from driveshaft mods, transmission crossmember mods etc. Now for the second half of the question what transmission did the early (89-90) 5.9l Cummins use, would'nt happen to be the same bellhousing pattern as the A block would it???

 

If you swap in an older 727 you're gonna be looking at building new driveshafts and crossmembers like you said, but also a custom transfer case adapter. Check to see what spline count and diameter the output shaft is on the 727. I don't know offhand what they are. Your '98's 46RE uses a 29-spline output, not sure of diameter. I would say that if you're gonna use a 727 to get the transfer case with it, but the older 727's were all mated to passenger-side output transfer cases, and your '98 needs a driver-side output transfer case. I don't know anyone that makes an adapter to mate your NP241 t-case to a 727 either, so you'd have to build it yourself if the splines even match.

I'd stay away from the early Cummins autos also. College roomate had one and put the third transmission in it at 90,000 miles. Also, you're going to have major computer issues with your fuel injection. Believe me, I've fighting them now. Your PCM will be looking for a bunch of electronics in the trans that aren't there.

The easiest fix is to get a heavy duty 46RE built by a reputable shop. Call Southeast Performance at 813-503-8069 or 813-886-6166, they'll steer your right. Tell them you were referred by someone at Dodge Forum.

My solution when mine went out was to replace it with an NV4500 5-speed manual out of a '98-'02 1-ton. It's only 3/8" shorter, so the stock driveshafts work. The trans mount is in the same place so the stock crossmember works. It's a 29-spline so the stock transfer case works. I just had to replace the brake pedal with a clutch/brake pedal assembly from a junkyard, cut a hole in the floor, do a little wiring, and build a custom bracket for the 4x4 shifter. Overall it was a pretty easy swap cause I used all stock Dodge parts. I am having computer issues right now, but I'm hoping to have them solved in the next week or so.

 

A little update, The cummins uses a different bellhousing pattern, But I do have the engine to go with the cummins transmission, so thats option C right now. As for the idea with the 727, I'm still considering it, as far as transfer cases, my stock 98' case I've been told "Might" bolt up, If not I'm thinking I might be able to use an NP204 or 205 from a Ford, the front output will be on the left side, and I'm pretty sure they will bolt up to the 727.