I have a 92 Ram LE shortbed 2wd with the 3.9 V6 and 5-speed, the engine is tired and it needs a new clutch. I can get a 93 Dakota 4x4 cheap 5.2 V8 with leaking automatic, is it possible to change engines and use the 5-speed and bellhousing behind the 5.2 in the Ram? What about wiring and computer, dash guages?

yes

Yes it's doable. The mechanical fitup should be straight forward. Check pn on the flywheel as the 318 is likely different balance.

Dash and guagues is simple, the senders are the same and pretty close location wise, might have to lengthen a couple wires.

Computer and it's wiring will be the most problematic. You'll need to add wires for the extra injectors. Either scavenge them from the Dakota harness and add to the d harness or possibly swap the Dakota harness.

You can try using the Dakota ecm but probably have a persistent check engine light since the ecm is looking for a automatic. Or find a pn for a 92 d truck with 318 and stick shift.

Check Mopar Action as this is basically what they did on their Dakota.

I swapped a 318/904 from an '87 to an '88 that had been V6/5 speed. I had to modify the driver's side motor mount bracket where it went on the cross member. other than that it was plug and play.

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What he said, but I'll add this , the Computer is going to be your only real issue, unless the trans is the NV2500/AX15 it won't last ...I don't know that the NV2500/AX15 was actually used in the later D150s (after1990)
The Bell housing is the same,. the Flywheel will work both engines are internally balanced.
Being the 5.2 is coming from a Dakota the V6 engine brackets should work as long as the 5.2 uses the brackets that bolt to the side of the block and not the Lugs.

i think the tranny will be a 3500----the oil pan will look different at the sump but should work--motor mounts are the same v6 to v8-the fan shroud on the v6 is longer--try to save the pilot bearing adapter...piece of cake...

Cool, I am not sure if I want to tackle this, but the donor is cheap, and so am I...

I did this very same swap year before last. It didn’t take much. You’re doing your clutch anyway. You’ll need a v8 flywheel and a pcm for a v8 five speed truck. Pretty straightforward swap. Take the injector wiring from the v8 automatic harness and splice them into your existing v6 five speed harness is what I would do, that would be simplest. You’ll like the truck a lot more with the v8 in it. And won’t be much difference in fuel usage you’ll find.

You will neeed a 318 flywheel if you intend to keep the injection, balance is not a factor as both v6 and 318 are neutral balance, the number of slots for the crank sensor to rear are different and it will not run with a bad crank signal.

You will also need to get a new pilot bearing insert, usually they come when you buy a pilot bearing by it self new but not in a clutch kit. The engine from an automatic will not have the insert ring but you can easily put one in.

Thanks everyone for the replies!

I was also going to post this part about the flywheels being different. The v6 one will bolt up but won't run right. I would splice in the harness from the donor truck, these OBD-1 harnesses are quite straightforward once you peel them apart. You will need to use the crankshaft position sensor from the V6 as the auto trans ones are too long. This is similar to the swap I did on my jeep except mine was originally carbed. I did a 5.2 with an ax-15 transmission and an OBD-1 harness out of a 94. Computer came from a 94 ram 5.2/stick shift off ebay or car-part.com harness was from an auto trans grand cherokee at the wrecker.

the automatic computer should work just fine if you already have one, I have used them with manual trucks and nothing bad happens, CEL dont even come on.