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Old January 27th, 2011, 09:20
lawsoncl lawsoncl is offline
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Join Date: Jan 2006
Location: North Idaho
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Re: Everything you ever wanted to know about the AW4

Originally Posted by kastein View Post
Some early ones did. 4.0L equipped early ZJs with the AW4 had the same bellhousing
Up to 1993.5, the ZJ 4.0 came with the AW4.

Originally Posted by kastein View Post
* ALL XJs with a 4.0/AW4 drivetrain have a separate TCU. 1987-1990 are (as far as I know, RENIX experts want to chime in?) all the same TCU,
I believe that is correct. The renix TCUs all had grey connectors and can be interchanged. There might be subtle changing in the shifting maps, but they can be swapped. The HO TCUs all had green connectors, and red seems to correspond to the Chrysler made trannies.

Originally Posted by kastein View Post
* All XJs with a 2.5/AW4 drivetrain (1987-1990 only) have the TCU functionality built into the ECU to the best of my knowledge. This is a very rare combination and not commonly found around here (they all rotted out long ago and were rare when new, most 2.5s got a 4 or 5 speed standard) so I have not verified it myself.
* All XJs with the 2.5/30something auto tranny had a unified PCM handling both the engine and transmission as well. Same rarity and lack of verification.
I can't recall if the 2.5/AW4 I saw at the salvage yard had a separate TCU. The transmission control wiring diagrams don't distinguish between the 2.5 and 4.0.
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