5 Speed to Auto ???

[biggwheels]

88 comanche 4.0L I6 5 Speed to Automatic Conversion

 

need some input on what i need and what needs to be done .... someone please help me i am doing this alone and i have never done this before

[Pete M]

Are you prepared to do some wiring? The trans is computer controlled.

[Wanker]

:hijack:

Could one use an entire wiring harness and ECU from an XJ instead of splicing into the MJ harness, or would this cause adverse effects?

:hijack:

[offroader461]

could but its pointless to swap the harness....everything should be there for both M/T and A/T...i know my MJ has the wiring to put an A/T in if i choose to..its just all tucked away...even the wiring harness for the TCU

[biggwheels]

so this A/T part of the wiring harness, where would i look for it if it is tucked away somewhere????? i don't ming the wiring part but if it is in there somewhere then why not use what i already got right LOL

anyone got pics or a link to a thread with pics ????????????

[mjeff87]

follow the main wiring harness under the hood where it comes out of the C101 connector (or thru the firewall if you don't have the C101) across the firewall from driverside to passenger side. Right behind the engine on the pass side there will be two sub-harnesses wired in to the main bundle. Actually it's one sub-harness and two multi-pin weatherpack connectors. The two connectors plug into the two wiring harnesses that come off the AT driveline, and the one sub-harness that's hardwired into the main one feeds back thru the firewall via an oval shaped grommeted opening, behind the dash, to the TCU.

 

My 87 2.5 manual MJ didn't have the extra auto wiring in the main harness, but 4.0 harnesses may be different (??). From what I can recall, there is no difference in underhood harnesses between the XJ and MJ (but there is a difference in the in-cab harness), so if your current one doesn't have the extra AT wiring, you could swap a same-generation XJ underhood auto harness in as plug-and-play. Then you'd have to only pick up a TCU and plug it in.

 

You will need an AT throttle body though. It's the same TB mechanically, but the TPS has a secondary output that feeds to the TCU. And you will need an auto kickdown cable and TB bracketry to install it.

 

HTH,

Jeff