jdjonesdr

My 1990 with auto transmission quit downshifting today.

Acceleration is normal, shifts fine and dandy, but when I'm at a steady speed, flooring it does nothing. It won't downshift to a lower gear. Doesn't matter what speed.

When I decelerate to stop, it is occasionally shifts roughly from 3rd to 2nd, but not always.

You may remember during my rebuild, I replaced all of sensors on the engine, so I'm not sure it's a sensor problem.

Two things: I washed the engine this morning, and that's when the problem started in earnest, but I noticed it did it a couple times in the last week or two.

The cable that goes down to the transmission that has the adjustment plunger is frozen and can't be adjusted, so I don't think anything happened there.

kjc

The Throttle Valve (TV Cable) is very important for proper shifting. I would address that problem first. Incorrect adjustment of the cable can damage your transmission caused from early or late shifts.

jdjonesdr

Thanks for that.

Like I mentioned before, it shifts up and down smoothly through the gears just fine, with the exception of the occasional hard shift down from 3rd to 2nd.

The problem is when I floor it to downshift one gear(what some would call "passing gear") it is not downshifting. It stays in whatever gear it is in at the moment with unimpressive acceleration due to the fact it doesn't downshift.

While we are on the subject, I'd love to know where I can get a new TV Cable. I'd love to change the one I've got.

EZEARL

http://www.jeepforum.com/forum/f11/t...g-gear-353785/

http://www.rockauto.com/catalog/x,ca...%2B1990%2BJEEP

jdjonesdr

BAM!

Thanks, brother. I've bought tons of parts from rockauto, but I couldn't find the cable.

Obviously, I was looking with the wrong description. You nailed it. Thanks.

I have another question for the board: is there any other reason for it not to drop into passing? Specifically an electrical reason?

I ask, because it was functioning fine until I washed the engine.

Or is this going to be an uncanny coincidence that the cable stretched/broke/disengaged while I was washing the engine?

In any case, one of the few things that haven't been replaced under the hood is that cable, and now one is on the way.

EZEARL

Your quite welcome.

Let's see how she shifts after the new cable is installed and adjusted. There is also something to do with the TPS that can be an issue. Could be it needs tested or replaced and adjusted. First things first though.

cruiser54

You got your TPS wet..............

jdjonesdr

Bingo.. I am always very careful with the TPS, even while it's almost new, due to the problems it brings if it gets wet.

I checked with the guy that was helping me when I washed the engine, and he admitted he had hosed it down some more when I was in the house.

And yesterday morning when I started it, the engine jumped right up to about 2500 rpms, and won't budge from there, so yeah, I think you're right on the money.

I just ordered another from Rockauto, so the cable and the TPS should be here next week.

And to add insult to injury, I had an electrical problem yesterday afternoon, and the little rascal wouldn't turn over. Got that fixed in short order though.

I'll let ya'll know what happens next week. Thanks again for your help.

jdjonesdr

Well.... that didn't work.

That turned out to be the cable that goes from the floor shifter to the transmission.

"A" for effort anyway.

So, anybody else have an idea of what that cable is called and where to buy it?

cruiser54

There is no cable that affects the down shifting of the trans....

jdjonesdr

Thanks Cruiser, Obviously, it would appear I am not identifying it correctly.

I am referring to the adjustable cable that goes from the throttle body down to the transmission. Here's a pic (red arrow)



What is that baby called?

If it doesn't control the downshifting when one presses the throttle, what does control the downshifting?

EZEARL

All right let's try this again.

MOPAR Throttle Body Kickdown Cable

MOPAR Throttle Body Kickdown Cable

Vehicle Fitment



1987-1990 Jeep Cherokee XJ (With 4.0L Engine)


Part Number:83503741-M

cruiser54

The TPS controls kickdown.

The item in the above post is misidentified as a kickdown cable. In fact, it's a Throttle Valve cable aka TV cable.

It increases the internal line pressure of the trans in proportion to the amount of throttle opening.

Soft shifts when you have little throttle opening, and firmer shifts when you're heavy into the throttle.

EZEARL

He's looking to replace the cable in his pic but I've tried to find the part using the MOPAR number above and no results at the MOPAR parts sites. Throttle valve cable or throttle body kickdown cable gives no results either.

cruiser54

Does he want to replace it because it doesn't downshift, or for some other reason?