how hard is it to switch to a HO with auto

[88mjmanche]

i have an 88 comanche with low output an a 5 speed. i just recently got a 92 cherokee an i want to put the motor and trans in it how hard would that be to do ?????????

[Eagle]

Putting the engine and transmission in is the easy part. Obviously, it's a direct swap.

 

The issue is that the HO engine uses a totally different computer, injection system, and ignition system. To do the swap and be able to gain all the increases of the HO, you'll have to rewire the entire engine compartment, and many people think once you go that far it's better to rewire the entire chassis. If you aren't good at and don't enjoy wiring, trying to convert a Renix to HO is probably not a good idea.

 

If there's nothing wrong with your engine, the HO really doesn't put out that much more horsepower than the Renix, and hardly any more torque. But it raises the torque peak from 2400 RPM to 4000 RPM. That's a trade-off that never made any sense to me for an off-road truck.

 

Why don't you just swap in an automatic tranny?

[JeepcoMJ]

apply the term "rewire" loosely. it's a matter of swapping wiring harness....there is no "wiring" to be done, just taking what's already there and replacing what came out of the donor.

 

 

you will need to swap the entire dash harness and make a crossover harness to the rear harness though...but that can be done with everything from the donor, and mfpdm just did a very detailed write-up on the crossover harness in the DIY section.

 

 

it's hardly a swap to balk at. took me one weekend to have it running, and the following saturday to button up the little things...and I had added issues of using a 95 steering column in it.

[Eagle]

apply the term "rewire" loosely. it's a matter of swapping wiring harness....there is no "wiring" to be done, just taking what's already there and replacing what came out of the donor.

 

 

you will need to swap the entire dash harness and make a crossover harness to the rear harness though...but that can be done with everything from the donor, and mfpdm just did a very detailed write-up on the crossover harness in the DIY section.

 

 

it's hardly a swap to balk at. took me one weekend to have it running, and the following saturday to button up the little things...and I had added issues of using a 95 steering column in it.

I hear you, Pat, but completely removing one wiring harness, putting in a completely different wiring harness, and THEN making up a home-brew connector to make the front half talk to the back half sounds a lot like "rewiring" to me. And it also sounds like a helluva lotta work if all you really need is to bolt an automatic tranny up to the existing engine, install the free-standing TCU, and drive it.