Transmission is procrastinateing ;)

[xjintx]

Did a search but did not really see my issue covered.

87 2.5L auto
Does not want to shift
Just returned from NM and the Guadelupe mountains. The XJ drove fine and no issues on trip was not really any off road just gravel roads and some altitude.
Before I left I had the diff's fluids changed and transmission checked. I replaced a seeping valve cover.
Had an issue with clogged fuel filter before leaving and replaced a cracked vacuum line.
Now on return the transmission winds out higher than normal before shifting. Finally shifts through all gears but seems late. That power/comfort switch seems to be working however not sure what it does.
Visually checked vacuum lines under hood... before I take it in.... any suggestions?

 

[insanity]

The power/comfort switch controles the shift points. If it is on comfort it could be holding the gears longer for a smoother shift.

 

[Ecomike]

I did not know the 2.5 ever came with automatics. I am assuming its an AW4 tranny with the 87 TCU. If so a worn TPS and the TPS/TCU grounds, loose dirty grounds, can cause your problem.

The power setting makes it shift later, at higher rpms than the comfort setting does. The power setting is for hills and towing.

 

[xjintx]

The switch does not appear to change anything. The light does come on and off. I assume there is a solinoid or something it activates??? Is it something I can check / repalce or does a dealer or transmission shop need to?

I guess I will need a shop to look at the TCU and such because I would not know if it was bad or going bad

Thanks for all the suggestions !!!!

 

[Ecomike]

I am assuminig it is the same tranny as the 4.0, AW4, in which case it could be the TPS going bad and or the TPS gound wire getting loose. Check out the "RenX files" thread for details on the ground and TPS issues that cause weird tranny shifting in 87-90 models.

The shifting is controlled by the TCU, but it gets its input from the TPS, power comfort switch, the NSS (what gear is selected, 1-2, 3, drive or Rev), and the engine rpm sensor (CPS to ECU, ECU to TCU) and vehicle speed sensor as I recall. Check the TPS gound wire and the TCU side voltages per the 90 Renix Fuel Injection manual with a volt-ohm multimeter. The steps are posted in a about a dozen threads on the "Renix Throttle Position Sensor", hint, use those words for a key word search in advanced and my user name as the post, poster.

 

[ExTankerGuy]

2.5 with an auto? I wonder if it has factory 4.56 gears...hmmm...

 

[xjintx]

Not sure...

You might be interested in the fact I bought it from the Air Force... an 87 with 69,650 miles

Still has cables for a military radio have not had time to trace out the pins so I'm leaving them incase I want to use.

Appears the radio(s) was mounted in center just behind the front seats... it's a two door.

Rubber matting no carpet which I like but has leather seats... hot for Texas

They told me it was a Staff car?

 

[Ecomike]

Do they have more to give away??? That is a rare bird indeed!

Not sure...

You might be interested in the fact I bought it from the Air Force... an 87 with 69,650 miles

Still has cables for a military radio have not had time to trace out the pins so I'm leaving them incase I want to use.

Appears the radio(s) was mounted in center just behind the front seats... it's a two door.

Rubber matting no carpet which I like but has leather seats... hot for Texas

They told me it was a Staff car?

 

[xjintx]

I can check next time I am down there. If you are a contractor for them you don't need to wait for auctions...

My son's business is a contractor for themso that is how we get in

I will check next time I'm in San Antonio to visit him.

 

[Ecomike]

I can check next time I am down there. If you are a contractor for them you don't need to wait for auctions...

My son's business is a contractor for themso that is how we get in

I will check next time I'm in San Antonio to visit him.

Cool! Always nice to have the inside track!