High reving auto

[ken]

My 94 3.1 Bighorn tends to rev a bit high for my liking. There is an adjustment on the throttle asembly for adusting what I assume is the kickdown control. Does anyone know which way to adjust this to reduce the tendancy to drop down a gear? Towards the spindle or away from it? Are there any other adjustments that can be done to fix this?
Thanks
Ken

[Graham]

Hi Ken,

My auto absolutely hates shifting if it is in "power" mode. It's so un-driveable that I always have it in normal mode.

Is your's in power mode by any chance?

If there is a simple way of adjusting the shift point, I'd like to try it too, but I always thought it was something to do with the internals of an Auto Gearbox.

Cheers, Graham.

[ken]

Yes Harry. Checked that.
Thanks
Ken

[PeterSchurms]

G'day,

I am not an expert but have looked at this same problem recently and got mine running really well. If I have got something wrong hopefully someone will clarify it.
There is a couple things that you can do to change the auto shift revs. I expect you have an electronic controled auto (most likely a AW30) so the things that you can change include. Oil and filter, Kickdown and TPS (throttle postition sensor)

1. Change the auto oil and filter,
Use a Dextron 3 equivelant. The gasket and filter is the same as a 95 Jeep Cheerokee. (19 studs from memory) This extra pressure will improve you cars shift patturn

2. Adjust the kickdown cable,
This is the cable that goes from the throttle body to the auto. Dont adjust the throttle cable by mistake.
Tightening the kick down cable will make the auto kick down earlier. Tightening the cable also boots internal valve pressure.

3. Adjust TPS,
The TPS is located on the throttle body and is black in colour. It is held on with two screws. It is essentially a variable resistor the varies a voltage sent to the auto computer. By loosening the screws and twisting this left and right you can alter the shift strategy. If you turn it too far you may raise a low or high, voltage error code. This is indicated by a flashing overdrive light on dash board. This is easy to clear by moving the TPS and then removing the battery terminal for 10 seconds.

Its just trial and error, Mine runs really well in Power mode so I expect its most likely an adustment problem.

Cheers
Pete

[ken]

Thanks for that Pete. I will get into it as soon as I get my caravan back on the road. 2 or three days hopefully.
Ken.

[ken]

I have adjusted the kickdown cable and TPI and it seems to have lost its tendancy to change down too much. The real test will be when I next tow the caravan but the signs are looking good.
Thanks for the help.
Ken

[ken]

I have just had a short trip with the caravan and the automatic is heaps better now. Thanks for the help.
Ken

[PeterSchurms]

Thats great news, happy 4wdriving!

[3vilc]

I have a similar problem, at a low idle the 'check trans' light on the dash flashes. touch the throttle a slight fraction or wind the idle control up and it stops. Assuming in this case that the pressure is too low and refering to the comment about adjusting the kickdown cable to increase valve pressure above.. maybe adjusting the kickdown cable could fix the problem. There are no problems with the idle set high, but maybe if I set the idle lower and adjusted the kickdown cable that would work better then having the engine idling at 1100rpm

Any thoughts?

Thanks,
Clive

[geeves]

Change trans fluid and filter and hope this fixes it Otherwise a trip to auto trans shop in oder $$$$$

[Graham]

Mine does the flashing trans light too, but only when it's idling below 500rpm and it would be caused by low oil pressure.

Do what Geeves says as idling at 1100rpm shouldn't produce low oil pressure.

It could just be a loose wire though...

Cheers, Graham.

[Dave M]

If your check trans lite flashes only when idling, but you are happy with the idle speed, you need to turn the TPS a tiny bit against the throttle opening direction until the lite stops flashing. If your idle is a little low, then bump the idle up with the stop bolt on the pump to where you like it and see if the lite goes away. I like mine idling around 850-900 so it doesn't shake like shite. Adjusting the pressure cable only alters throttle pressure; not shift speeds.

[3vilc]

where is the TPS sensor on the diesel? assume its on the pump somewhere but havent really had a decent look down that side of the engine