David

I know someone here has to know something about transmissions. I am looking for some info about computer-controlled auto trans's. My '99 Jeep Wrangler (59K) has a shifting problem that I need to resolve.
#1. Hunting at low speed (20 or so)
#2. Delayed upshift, light throttle (2-3)
#3. Erratic/ inconsistent 2-3 shift
This problem comes and goes whenever it feels like it. Upshift at 50+% throttle is fine. If I leave shift lever in 2 till speedo is past about 42 mph, then shift to "D" and let engine return to idle momentarily, then it will shift to 3 most of the time with no prob. This is all from standing start. If in motion, and trans downshifts from 3 to 2, it will upshift back to 3 normally.
Is there a diagnostic terminal for the trans alone? I put a scanner on the POS, but there were no stored codes relating to the trans, only one code related to "no communication with dashboard" and that has been resolved.
BTW- I have owned this "car" since new.

Vinny P

There is no dedicated transmission diagnostic connector. Your Jeep is O.B.D.II, the connector under the dash will read trans codes. The best scanner for that Jeep is the Chrysler DRB III. It will scan all the control modules very easily. It may be something as easy and cheap as a speed sensor that is going bad. But without any codes, it would be difficult to pinpoint.

mcollinstn

EGR problem? Erratic engine vacuum signal can do weird things regarding shifting of transmission. Just a thought.

David

I had considered vacuum signal as a possible cause, but it doesn't appear that the trans has a vacuum modulator. It is irritating when it doesn't want to upshift or act like it's going into neutral instead of 3rd gear. Sometimes it acts normal and other times it doesn't want to shift. I guess I may have to start unplugging and re-plugging every connector on the damn thing and see if that's the problem. Previously, the "check airbag" light would come on, for no particular amount of time, and at the same time, all the gauges would stop functioning. Then it would go back off and the gauges would come back to life. I recently had to remove the entire dashboard assembly to fix the heater (defrost) flapper, that was never properly assembled from the factory (or so it appeared), and have not had any problem with the "check airbag" light, or the gauges since. My assumption there would be one of the connectors was not seated properly. That also probably accounted for the code about "no communication with dashboard".
I have also checked linkages, but there doesn't appear to be any available adjustments to the kickdown, which I know used to be critical to line pressure in pre-computer TF 904 transmissions.

Vinny P

There are no mechanical adjustments you can do to that transmission. The computer controls everything.

David

It seems like a computer controls my life, lol, so why should the car be any different?
Looks like I may have to invest in a scan tool of some sorts.

FWK

David my dodge dually did the same thing it had a bad t.p.s. How are things going? Forrest

Vinny P

David,

If you happen to be up in the New York City or Long Island area, I would be glad to scan it for you.

David

Thanks, check454, for the offer, but as of the moment, I don't have any plans to visit that area.
Hey Forrest, how's it going?
Amazing, but not really, today it's acting normal for a change. But I'm sure that won't last long.

Ted G

iTrader: (1)

There was a problem with the bulkhead connector on some Wranglers that was covered under a recall or a TSB, yours may have been fixed inadvertently when they did the dash. But it may still be your problem due to improper readings to the ECU. There was alsoa problem with that trans tearing up a bushing inside and filling the valve body with metal-thus causing erratic shifts. You may want to take a peek in the pan before it leaves you walking.