upgrading from 2.5l to 4.ol wiring

espyking83

New member
i am wanting to swap in a 6 cyl and a ax 15 to my 92 wrangler.

i got a hell of a good price for labor to drop in another 4 cyl but the mechanic said he didnt want to do the wiring if i upgrade to a 6 cyl.is it really that difficult?is there some type of adapter that i can buy and use it with my 4 cyl harness?

another thing,i get mixed responses when i ask if i have to upgrade my drive shafts or axles when i step up to a 6,can anyone give me a definite answer on this?

and yes -i am a newb.
 

It's going to take more than just a wiring upgrade if your dropping in a 4.0 I6 that's fuel injected. A PCM will also be required. Also, if your going to an I6, i would recommend you also upgrade from an AX15 trans.
 
I dont think it is worth the trouble to replace the 2.5 with the 4.0; might as well go V6, as it will be easier, and there are wiring harneses already available...
 
I dont think it is worth the trouble to replace the 2.5 with the 4.0; might as well go V6, as it will be easier, and there are wiring harneses already available...

so if i just go with a v6 i will only have to purchase a wiring harness and thats it?

now that i think about it i may just go ahead and get another 2.5 dropped in.i dont really need all the power being that i don t really take my jeep into anything to thick,my little 4 banger does just fine.

is the ax -15 transmission compatible with the 2.5l?just in case i decide to upgrade some time in the near future.
 

OH boy... unless your putting the same motor in, there is no Easy way to do this. Doesn't matter what you put in, V6, V8, 4.0, 4.2, viper V10... unless it is a 2.5, you WILL need to replace your motor mounts, and I mean cut off your factoryones off the frame and weld on new ones. Wiring will be a PITA,a custom harness will probably have to be made, one way around this is get the entire harness from the donor vehicle and splice it into you factory vehicle, if you have never done it, you will probably be lost. You can buy a "adapeter harness" some will require further mods, most are not 100% plug and play. Your transmission will have to be replaced, the ax 5 is junk, the ax 15 is only moderately better, look into a nv3550, nv 4500, sm 465, or some typ eof auto, 4L60E or 700R4 are very popular. Your T case will need to be modded regardless of what you do. new radiator, drive shafts will also be needed. Now you have some serious power in the engine bay, your D35 rear will last a little wile with stock tires and open diff, but once you put on a lorger, heavier tire or lock it, Ka BOOM time for a new rear, front is sure to follow.


Now, you can upgrade to a ax 15, again, slight upgrade. you will need to change the t case main shaft from (and don't quote) a 21 spline to a 23 spline main shaft. or swap the entire t case from a 6 cyl jeep over. This is where My brain gets a little fuzzy, you will need to run the external clutch slave, but the transmission should bolt up to the 2.5.... again, real fuzzy on that part. research and see whats out there.
 
The ax15 will not bolt up to the 2.5L unless you get a bellhousing from a 2.5L Dakota.
Thats it!! The 2.5 dakota came with a AX 15. Thanks for shaking my brain. and I also think I was wrong, I think the dakota ran a internal slave as well, so should be fine.
 

this thing won't let me put a link in here for you, so if you can pm me with an email address, I'll send you all the info on the wiring and changeout for what your doing.. thanks.. wayne
 
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