3.0L manual trans to 4.0L automatic trans
 

Let me start by explaining. I wrecked my 1999 Rangwr that has a 4.0L V6 automatic trans. Rear ended a semi truck. Engine and trans is still fine but body and frame not so much. I have a 1997 Ranger with a 3.0L V6 manual trans but the heads are blown (was like that before i bought) only paid $100 dollars. I know it is impossible to just swap the engines because the 4.0L engine and 3.0L trans will not match up. I was wondering if it is possible to switch both the engine and transmission from my 1999 Ranger to the 1997 Ranger. If so, how do I do this? I need to get a truck running if this is not possible I will just buy a motor for the manual 3.0L V6 manual but I would rather have my more powerful 4.0L V6 automatic and not spend anymore money. Thanks in advance.

Welcome to the forum

Not a plug and play, less trouble to sell the 4.0l OHV and automatic and get heads done on the 3.0l Vulcan engine.

For any engine size swap you need the "new" engines computer and wiring harness and that needs to be interfaced with the "other" vehicles Power system, no plug and play
And the engine with transmission as you surmised.

1997 Ranger used a 2 line fuel system running 35psi fuel pressure.
In 1998 all Rangers got a 1 line system(Returnless) with 65psi pressure.

This shouldn't be to hard to work around but there will be some connection issues.

You can use a 3rd party floor shifter for the automatic or swap over the automatics steering column, you need to remove the brake/clutch pedal assembly and install the brake only assembly.

Most of it is just wrench work, not to complicated, and in the end if everything goes perfectly, you would have a damaged title(VIN doesn't match engine size) vehicle that really isn't worth much, because you can just go out and buy a stock 4.0l Ranger.

So IMO I would fix the 3.0l and drive it with a For Sale sign in it, if you get the right price buy another 4.0l Ranger

Or fix the 3.0l for a driver and hold on to the 4.0l/auto, look for a Ranger with blown 4.0l OHV engine, or bad automatic, 1998-2000
2001 and up Ranger used 4.0l SOHC engine so not swappable with your 4.0l OHV, but transmission is, so.............