Swap XJ 4.0 Engine and auto trans into 88 YJ w/ auto trans and 4.2 w/ Howell EFI? - JeepForum.com
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post #1 of 1 Old 03-09-2017, 11:11 AM Thread Starter
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1988 YJ Wrangler 
Join Date: Mar 2017
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Swap XJ 4.0 Engine and auto trans into 88 YJ w/ auto trans and 4.2 w/ Howell EFI?

I'm looking to swap a 4.0 engine and 4 speed auto trans into my 88 YJ (currently has the 4.2l I6 w/ Howell EFI conversion). I am considering 2 possible donor vehicles, a 1995 XJ or a 2001 XJ. The 2001 can be test-driven, the 1995 can't as it's missing some parts but I can still verify engine runs.

Can the 4.0 block from the 2001 XJ (distributor-less) be used with my existing distributor?

Also, I know that up to 1995 the XJ's had separate computer to control the transmission. Would a 2001 XJ also have a separate computer for the transmission, or would the trans be controlled by stock ECM? I want to keep my existing Howell EFI system instead of switching over the entire wiring harness from donor vehicle, especially if OBD2. So it seems like 1995 XJ would definitely work because transmission has separate computer, is same true for 2001 XJ?

Also, if 2001 XJ transmission is controlled by stock ECM instead of separate transmission computer, could it be adapted to work with the transmission computer from the 1995 XJ?

What about speed sensor for either of the transmissions? It is my understanding that the 1995 XJ transmission has a mechanical speed sensor, what about the 2001 XJ? And anyone know about whether the mechanical speed sensor from 95 XJ can be adapted to my stock YJ transfer case?

Anyone know if YJ transfer case will mate to either of the XJ transmissions without re-clocking?


88yjay is offline  

4.0 , cherokee , swap , xj , YJ

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