Its been awhile since i posted but i still read from time to time. i have a question about converting my 1992 d350 5speed to 4wd. I have found a 1990 w250 cummins it is auto and has 118,000 miles on it, regular cab long bed. Can i do the conversion with the w250 as a parts truck? do i have to get a new 4wd transmission or just a tail shaft and tail housing on my transmission. I am going to keep it 5speed.

Thanks
Ryan

 

You'll need a new t-case also, the auto tcase is 23 spline input, while the 5 speed is 29(maybe 27) spline. They're different, and not easy to change as you have to do some machining.

 

the tail housing on a 4x4 has to let the bigger coupler (29 spline) in, also you need the next piece sometimes called an adapter: it also serves as a mount. Additionally, that piece has the proper setup for the 3 holes to bolt on the transfer case linkage ( on an auto the 3 holes are spaced differently)
If you modify the auto NP205, get gasket and seal kits, as well as the roller bearings: it is time consuming but not that difficult
your speedometer will work off of the transfer case: check that it is for the gear ratio/wheel size you have
a few switches: neutral safety and backing lights should be the same, if you want some sort of light indicator on the dash that 4 wheel drive is engaged you might have to come up w/ sthg
if you drop the tranny to see how everything bolts up before installing, check your rear main seal, your throwout bearing, clutch and all.
all I can think of...

 

whats wrong with the w250? would it be easier to swap ur manual transmission and associated parts into that?

 

you're also gonna have to change the engine cross member, unless you plan on sticking enough lift under it for the front diff to clear it. plan on pulling the motor to do so.