I have a 1990 4x4 with a rebuilt (8 yrs ago) 22RE in it, and some hard miles since then. I also have a 1988 2wd with 22RE and 102,000 mi. Found out 88 had a broken headbolt and had a bad cylinder in it. I am doing a complete rebuild of the 88 engine, bored out .40, new pistons, complete head job, etc. Now here is my question...Can I take the 1990 engine and put it in the 88 2wd, to be sold, and then put this newly rebuilt 1988 22RE in the 1990 4x4 truck? Will the 90 swap with the 88? Will all the wiring harness and vacuum lines still work? I want to build the 4x4 into the best truck it can be because I am keeping it for life or longer. Thanks.

 

Take a look under both hoods, I know that at some point between the 80s and 90s toyota changed all of the wiring connectors, and maybe the whole harness. The two models have different fuse boxes in the engine compartment. If you have identical engines they will be the same. you can definitely make it work for the 4x4, but if they're different you may have to cannibalize the other truck's harness to make a franken-harness of sorts making selling the 2wd difficult. That's just off the top of my head, I'm sure someone else will be able to tell you more.

 

The two harnesses will probably be different because the 88 is two wheel drive and the 90 is four wheel drive. For 4Runners the 88 is 1st gen and the 90 is 2nd gen. If these are pickups you're talking about, I'm not sure how the generations work. But I just checked on http://en.wikipedia.org/wiki/Toyota_Hilux and this is how they break it down:

83-88 4th gen*

88-97 5th gen*

*This Wikipedia's info which I am not claiming to be gospel. I'm sure someone who knows the pickup gens will chime in. I know 4Runners.

Knowing what I know about the 4Runners, the 22re's were changed very little from the 1st gen to the 2nd. The intakes are a little different so the harnesses may be as well.

Check out the intakes...the 88 should angle down. Is the 90 straight? What you are probably gonna have to do is find pin outs for the motors and see what's up.

 

The long blocks should be the same, if not the whole engine. It shouldn't make a difference that one was 2wd and the other 4x4. The engine generation didn't follow the body generation. 1984 was the last year of the old 22RE, 1985 was the first year of the new 22RE. Some of the visible differences between old and new are: The old 22RE has a sloped valve cover, double row timing chain, round exhaust ports. The new 22RE has a more square valve cover, single row timing chain and pear shaped exhaust ports. Heads and blocks aren't interchangeable between old and new due to deck height.

 

Oil pans and of course the pick up tubes are different between 4x4 and 2wd trucks.

The reason being the front differential.