Throttle kick-down

My '88 wagoneer seems underpowered.. sort of. it works well, but the throttle won't kick in the passing gear unless I put it to the floor. My friend just hits 3rd and makes the engine shift, but I don't like this plan, and am looking for an option that would give me the juice 1/2 inch earlier. Is there an adjustment to be made? cable to be shortened? other options welcome. (the comfort/power switch aint enough)

I´m not a a AW4 expert, but have worked on a few relatives. The kick down cable isn´t only, for passing, it also has something to do with pump pressures and throttle position (more pedal less pressure) moving the downshift point higher, could cost you some pump pressure (slip the clutches? soft shifts?). Many people complain about it, shifting into passing gear (downshifting) on even moderat hills, just the opposite of your problem.

This may sound odd, but do you have Trans fuse on you under-dash panel like I do in my 89? I drove mine for a couple of months, thinking that the tranny was dying or the motor was (173K). I adjusted the kickdown cable, no change. I came across the blown fuse by accident and when I replaced it.......my performance came back, the trans shifted like it should and the world became a better place.
Hope it works for you too.

Its not that it is dying, like when I have the switch in "comfort", but I want it to perform the way it does in "power" when it is in "comfort" or at least make "power" seem like, well... POWER.


Maybe I need new gears.

Like I said, I´m not a AW4 expert, Dexron III seems to be the recommened fluid, Chrysler ATF 3 or 4 don´t know (I bought mine from a dealer, might have had the wrong fluid in there). Dexron is supposed to grab some better.
The TCU controls most tranny functions. Some Toyotas (4 runners) and some Lexus have pretty much the same tranny (A340-A340H), don´t know if the TCU might be adaptable or the one you have, trainable (reprogramable).
But I doubt the answer is in the kick down cable.
I just got a 88 XJ with the AW4, soft shifts, some hunting. Noticed the oil was faded (a little yellow) changed to Dexron III, just to clean it a bit ( a throw away load) and am going to drain it again and replace the filter (hope to get rid of most of the old oil from the torque converter).
Shifts a lot better now and there seems to be a real difference between the comfort setting and the power setting, that I never noticed before.

The TCU uses the TPS as one of its inputs to determine shift points. You might want to check that the TPS is set correctly.

A buddy of mine told me what most people think is a transmission problem is actaully an engine problem.

You could be suffereing from a stuck EGR valve and/or a dirty throttle body. I had a stuck EGR and for the next year the XJ drove worse and worse. I took it back in and the dealer mechanic said "dirty throttle body".

When I had it cleaned at the dealer the mechanic hooked up the test set and made sure everything else was working well.

Also depending on how many miles on your XJ you could have a partially stopped up cat converter. I had mine changed at 125,000 and waht a difference, it was like taking a cork out of the tail pipe. Do you notice your front seat passenger floor getting very warm?

Hope that gives your some ideas.

PaulJ said:

The TCU uses the TPS as one of its inputs to determine shift points. You might want to check that the TPS is set correctly.

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YES! Also check the ground wire from the TCU to the TPS.

Adjust your TPS (Throttle Position Sensor).

The TCU gets the signal to kickdown the transmission from the TPS, so just give it an adjustment, (you might have to replace it if it tests bad).

Do you have a repair book (Factory Service Manual is the best), if so it should outline adjustment of the TPS.

Sequoia

Ok, so I'm clueles as to how to check the Throtttle position sensor.
Please tell me it is a screwdriver, not a dedicated electronic gizmo.

Cleaned the ground to the TCU, oil dipstick bracket Where the ground wire from the battery runs. All I gotty say is wow, what a difference. I think I found the power and downshift you where talking about, at least in my XJ. Dexron III, helped some, the TCU ground really made a difference.
I got a tendancy to work from easy, through cheap, to complicated, before I try expensive. Parts here are expensive, about double the cost of the States and there are many knockoff/pirate parts, often worthless.

TPS is probably the problem. AW4 is computer controlled and usually any shifting problems are sensor related.

As for the Cat. Yep, the first thing that went after my rebuild was the cat. 1 day and it gave up. WHAT A DIFFERENCE when the new one was put on. It was like someone superchaged it.