Can someone explain this...

I am a new owner of a 1990 Cherokee Lerado, I-6, automatic tranny... my question is why is it always "short" shifting? I changed the filter and fluid (not out of the torque converter yet) but still it always shifts gears at 1800 rpm, very rarely does it get over 2K. Could that possibly be the tranny switch on the dash? It is broken and I assume it is in the "comfort" position. I am just wondering if this is something I should be conserened with... I have a few issues with the vehicle and am trying to take it one step at a time, before I run it into a tree and be done with the whole thing... LOL Any help you can give me will be great...

Thanks
Mike

I barely ever used the comfort position on the switch (mines a 91, last year they had it), but the few times I did I do remember it lugging the engine a lot. What happens if you give it a good amount of gas? It does get over like 2500 right?

The highest I have got it is 2200. It has alright pick-up I guess, it just doesn't really down shift and put you in the seat. Thinking about it I guess it does lug the engine... well it kinda glides... I still get up and go, it just glides into it.

Mike

Hmm...well tomorrow I'll put mine back in comfort and see what mine does and report back to you. I'm sure someone on here can chime in as to how you can repair that switch as I haven't ever looked at it.

Soft shifts can be caused by the TV cable needs adjusted.

what does it idle at?

The comfort position is pretty gentle, but it shouldn't shift quite so short if you put your foot into it. Have you checked the throttle cable adjustment?

The kickdown cable on this is very easy to adjust. Put the tranny in "park." At the engine end of the cable you'll see where the sheath attaches to the throttle body. There is a large button shaped sort of like a capital "D." Push that button down, and shorten the cable as far as it will go. Now pull the throttle to its wide open position. The cable will now be adjusted, and if it was off before, perhaps it will improve something.

The power/comfort switch is very simple. It's just an on/off switch with an extra ground for the indicator light. Open (off) is comfort and closed (on) is power. If the switch is broken and you want to set it permanently to power, short terminals B and C (black/yellow and tan). You can do this simply by pulling the connector off the switch and jumpering the terminals on the connector with a piece of stiff wire. Make sure you don't use terminal A (black) which is the ground for the indicator light.

Later models dropped the switch and all are permanently wired to "power."

langer1 said:

Soft shifts can be caused by the TV cable needs adjusted.

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True, but it sounds like it's shifting at too low of an rpm. Incorrect shift rpms is usually caused by a bad TPS sensor.

lawsoncl said:

True, but it sounds like it's shifting at too low of an rpm. Incorrect shift rpms is usually caused by a bad TPS sensor.

Click to expand...

I'm not sure I was looking at "It just seams to slid into gear" but it sure could be the tps.

Mine shifts pretty early and the torque converter locks up real quick in the comfort mode, but it will kick-down if I mash the pedal. I usually leave it in power mode and don't notice a difference in mileage. Ideally, I want something in between the two modes.

lawsoncl said:

Mine shifts pretty early and the torque converter locks up real quick in the comfort mode, but it will kick-down if I mash the pedal. I usually leave it in power mode and don't notice a difference in mileage. Ideally, I want something in between the two modes.

Click to expand...

Same with mine although Power mode mileage is 16-18 and Comfort Mode mileage is 20-23.

It usually idles at 200-300, kinda low for my taste. But I am not sure if I can bump it up and not mess anything up. Is the kickdown cable connected to a vacuum can, looking thing, on the fire wall? I have a cable that is not moving and that is what it is attached to... I will try out the suggestions probabily thursday... will let you all know how it goes.

Thanks for the help
Mike

The kickdown cable usually attaches to the same lever as the throttle cable (from the accelerator pedal.)

The "can" looking thing on the firewall (near the centre, above the engine, right?) is the vacuum servo for the cruise control - that's not it.

Adjustment is exactly as MCurrie described - and takes about two minutes.

I might have to take a pic for you. Where'd I put that digital camera, anyhow?

5-90

I had the same problem in my 89' XJ, it was a bad TPS scensor, it is located on your throttle body. It might just need to be adjusted right. good luck.

I am a little confused at some of the posts, a TV cable is a throttle valve cable that "acts" as a tps sensor for old school transmission set-ups. It adjusts line pressure(shift feel) and shift points. A kick down cable is just that. Used for passing mode only, not related to shift feel or points. Typically on old carburated set-ups the TV cable is mounted next to the throttle cable on the driver side of the carb and the kick down cable is on the passenger side of the carb. So is this jeep using tps just for fuel management and it has a TV cable for the tranny or is the cable shown above a kickdown cable?

Typically when a TV cable is too tight the shifts come early but are firm, Kdplayn didn't mention firmness.

If they are soft then I would lean toward the tps sensor. Maybe some one adjusted the set screw.

I'd also check for vacuum leaks.

On a jeep the TV cable is only the pressure control, kick down is controlled by the transmission control computer with signals from the TPS and the speed sensor inputs.

Thanks for the info, so he should be having a tps problem right?