i am just looking for a little advise. i have a 94 crew cab dually with a 454 gas motor and a 4l80e trans. i am done with 8 mpg and have decided to swap in a diesel engine. any suggestions on what is the best way to go? i am not opposed to any combination, also if this works out i am planning to do the same thing on my p30 chassis motorhome. from what i understand the 6.5 turbo motor seems to be expexsive to repair and breaks down alot. i was thinking about a duramax, a cummins, or maybe even the 7.3 navistar. come on guys let me have some plusses and minuses to these combos.....thanks

With a duramax as long as you could get the allison transmission to fit, you would have a bullet proof powertrain combination. I don't think other than getting a duramax out of a van with the 4l80e(I think thats the transmission) you could couple any other trans up to it as the duramax ECM communicates with the TCM all the time.

If you went Cummins you would have a great engine and after beefing up the auto or going with the manual it would be another great powertrain. Only problem with a Cummins, is that it is a long engine because it is an inline 6 so making the engine fit may be another issue.

I don't know a thing about the 7.3 Navistar so I can't comment on that.

Hope this helps and welcome to the Diesel Place.

Cummins, avoid all the wiring/electrical problems

if i go with a cummins what trans should i use and what kind of hp and tq numbers can i get. i would be towing a 10k lbs trailer and i would prefer to get a trans with an o/d

nv 4500 or nv 5600

http://www.fordcummins.com/

I now it says Ford Cummings, but I think they're getting into Chevys too.

You can continue to use the 4L80 tranny. It will hold up okay, but you will either need to use a tranny control module or put a few sensors on the engine to fool the existing computer. There are adapter plates available from Cummins because GM put 4BT engines in P30 vans.