Hi guys I usually lurk here a couple times a week and it seems like the right place to post this question: I just bought a 84 crew cab 1 ton 4x4 short box that has a newer style 5 speed installed in it, I bought the truck planning on swapping the cummins out of my 91 4/4 ton regular cab auto 4x4 into it.I know that a couple of guys on this site have done this swap and was looking for some tips on the easiest way to do this swap and what do I need to do to the wiring and can I keep the 5 speed in the 1 ton?
Thanks

 

I'm assuming you mean that the 5 speed is an NV4500? If so, you just need the 2nd gen clutch housing and a flywheel and clutch to go with it to get the diesel mated to the 5 speed. I'm not sure how to get the clutch working, though. The '84 has a mechanical clutch linkage but the diesels were all set up for a hydraulic clutch. Perhaps some linkage cobbling will do the trick, but you'll probably need to convert to a hydraulic setup.

Wiring wise, I don't think you'll need to do much to make the diesel work. As long as it's an early '91 with no computer I think you'll just need to wire up the KSB solenoid, the air heater grids (not absolutely necessary if you live in the south), and add WIF and WTS lights if you want them.

 

I finally got the home tonight and It looks like it already has a hydraulic clutch.I think my 91 has a computer as I assume it is the big box on the drivers inner fender.Does the diesel have a different bellhousing for the five speed verses the gas bell housing?.How do I tell if its the nv4500? would it be easier to use the wiring harness from my 91? Sorry for all the questions but somebody must have done this swap and knows all the shortcuts. Thank in advance
Grant

 

If you have a hydraulic clutch already, you should just need a '94 and newer bellhousing and clutch assembly. The diesels use a different bellhousing than the gassers. I doubt anybody put a Getrag in a gas powered truck, but to make sure, just crawl under the passenger side and look for a tag on the side of the trans that says "Getrag gears". If you can't find one, it's a NV4500. Whether or not you want to use the wiring from the '91 depends on how "factory" you want the completed project to be. If you just want a running truck, all you need is to run the old coil positive wire to the shutdown solenoid. If you want the WIF and WTS lights and the air heater grids to work, you'll need to swap in the message center and the computer.

 

Thanks for the answers. Out of curiosity why does the bellhousing and clutch have to be newer than 94? I have seen 5 speed diesels older than that.Thanks again

 

89-93 5spd diesels used the getrag tranny, 94+ use the New Venture tranny

 

ahh I see, Thanks

 

Some more hurdles to jump :
You will need the 94 up engine adapter and 94 up starter for the diesel. If you look in this forum somewhere way down the line. You will find photos of my 6 speed swap under "first gen 6 speed. The NV4500 and NV5600 both have the same bellhousing bolt pattern which is different than the pre 94 diesels. The photos show the difference in the adapters and starters.
Good luck, I know you can do it ;D

OK I found the "6 speed first gen" on page 7 of this forum.
there are somne photos of the adapter and starter differences

 

Thanks again guys, I am just trying to decide now if i'm going to gut my 1991 4x4 or sell it and just look for a donor motor and parts. I originally planned on using my truck as a donor as the only crew cabs I could find were 2 wheel drive longboxes and thought I would need to use the running gear out of it to end up with a 4x4 crew cab. I ended up with a shortbox 4x4 so it might be best to just look for a motor or a damaged 5 speed 2 wheel drive truck.

 

For some reason Dodge did not make a crew cab longbox 4x4. At least far as I know all crew cab longbox's were 2wd. Maybe they made one early 70's on back, but I don't know.

 

I think I am going to try to find a donor truck other than my 91. What years didn't have a computer? It just seems like it would be a easier swap without dealing with that. Also will the bell housing be different going from gas to diesel or do I just need to change the engine adapter that "Frostie" mentioned. Thanks again guys
Grant

 

Grant
Get your self a 91.5 to 93 CTD and swap all parts over, it's almost a direct bolt in swap. I have done this swap and if you need help or advice just IM me and I will help as best I can . The swap is fairly simple, you do have to modify one motor mout hole on the frame but nothing major. As far as the computer stuff goes as long as you have a complete Donor truck just swap every thing, that way you wont have to "make it work" just plug it in and go.
The only differance you will have from me is the trans type (I kept the Getrag) but with the parts off the back of a '94 CTD you will be able to bolt it up

 

Thanks, I will keep you in mind when I start.
Grant

 

Sorry to drag this topic up again but can anyone tell me if the diesel has a different bellhousing than the gas engine or is it just the adapter that makes a gas nv4500 fit a diesel. I have a nv4500 that had a 360 bolted to it and think that all I need is a 94 and up adapter and starter but can't quite confirm that by reading the previous postings. What clutch and flywheel would I need? I read somewhere that there is a early nv that has the same splined shaft as the getrag so I am a little confused about clutches now.
Thanks Grant