Problem: Jeep doesn't like overdrive...sometimes
#16
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Year: 1996
Model: Cherokee
Engine: 4.0 HO
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Intermittent TCC lockup problems- if you have verified the TPS is operating properly and the tranny throttle cable is adjusted correctly....one more thing to check is the ground to the TCU and transmission case. Despite what the service manual says, the solenoids primarily ground through the case, not the wiring harness.
Black wire- D7 at the TCU should be ground. Check resistance from there to battery (-). If you see anything other than zero ohms, fix the ground.
Repeat from transmission case to battery (-). If it doesn't show zero ohms, fix or replace the ground to the tranny case.
Also- on (IIRC) 98? or newer the NSS comes into play, it has an added function of reporting what gear you have selected. It's not impossible that a flaky NSS could cause TCC lockup problems.
Black wire- D7 at the TCU should be ground. Check resistance from there to battery (-). If you see anything other than zero ohms, fix the ground.
Repeat from transmission case to battery (-). If it doesn't show zero ohms, fix or replace the ground to the tranny case.
Also- on (IIRC) 98? or newer the NSS comes into play, it has an added function of reporting what gear you have selected. It's not impossible that a flaky NSS could cause TCC lockup problems.
#17
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Year: 1994 sport 2dr
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Engine: 4.0 ho
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I had the same problem with overdrive. My speedo was also having problems staying in the same spot for too long. I replaced the vss and all is well. its on the back of the transfer case
#18
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Year: 1996
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my prob is finally solved for now i started messing with the kickdown cable after 4 or 5 readjusts i think i finally got the sweet spot it shifts real good now.
thank s for the advice everyone this site is great!!!
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#19
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Year: 1996
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Engine: 4.0 H.O. inline six
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I had a similar problem last year where I couldnt get the jeep to stay in overdrive. It would downshift to 3rd if I wasnt tailgating a semi to catch a draft. I was afraid of trans. trouble, but it actually ended up being a clogged cat. converter. As soon as I replaced it, the problem completely went away. Just a thought, as sometimes we head in the wrong direction on the problem flowchart.
#20
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1990 Jeep Cherokee 4.0L - I have had Torque converter problems (for years) in which the TC would come out of lock up after the vehicle had been run at operating temperature for a while (e.g.,30 min or more) and especially after running it, turning it off for a few minutes, and then getting back on the road. (After getting back on the road, within 10 minutes, it would drop out of lock-up, like clock-work.)
It also would sometimes hang in lockup, and would only come out when I tapped the breaks.
I had talked with several trans. mechanics, but they could give a good answer other than to let them take it apart for a costly eval or rebuild. (One dealer mechanic did speculate that it was either "valves/solenoids" or "TPS" related, based on the symptoms.)
After reading all of your articles, and others on this forum and other forums, I did "much" systematic testing (mostly electrical) of the TCM, TPS, break pedal switch, etc, with a multimeter, and finally found that the problem seems to have been a "poor connection" at the connectors where the TPS transmission pigtail connects to the wiring harness that goes to the TCM. (The voltages and resistance values for the TCM-TPS side were "off target" some of the time and "on target" at other times. The ECM-TPS (computer) side voltages and resistances were consistently fine.) After visually observing the TCM-TPS "socket" connectors, I noticed them seemed a little more "open" that I would have expected. (My TPS has been replaced at least twice--one was dealer recall.) I finally used needle-nosed plyers to carefully crimp the three connector sockets and then attempted to open the pin connectors at the TCM-TPS trans. pigtail and wire harness connector, and the after re-connecting them, the voltages and resistance values were "on target" according to the specs. and all of these writeups." (If you try this, becare ful or you will easily break the thin circular plactic shrouds that surround each of the "pin" type connectors"--probably will not hurt anything though.)
Thank you for the writeups. I hope this helps someone else, too.
CherokeeWill
It also would sometimes hang in lockup, and would only come out when I tapped the breaks.
I had talked with several trans. mechanics, but they could give a good answer other than to let them take it apart for a costly eval or rebuild. (One dealer mechanic did speculate that it was either "valves/solenoids" or "TPS" related, based on the symptoms.)
After reading all of your articles, and others on this forum and other forums, I did "much" systematic testing (mostly electrical) of the TCM, TPS, break pedal switch, etc, with a multimeter, and finally found that the problem seems to have been a "poor connection" at the connectors where the TPS transmission pigtail connects to the wiring harness that goes to the TCM. (The voltages and resistance values for the TCM-TPS side were "off target" some of the time and "on target" at other times. The ECM-TPS (computer) side voltages and resistances were consistently fine.) After visually observing the TCM-TPS "socket" connectors, I noticed them seemed a little more "open" that I would have expected. (My TPS has been replaced at least twice--one was dealer recall.) I finally used needle-nosed plyers to carefully crimp the three connector sockets and then attempted to open the pin connectors at the TCM-TPS trans. pigtail and wire harness connector, and the after re-connecting them, the voltages and resistance values were "on target" according to the specs. and all of these writeups." (If you try this, becare ful or you will easily break the thin circular plactic shrouds that surround each of the "pin" type connectors"--probably will not hurt anything though.)
Thank you for the writeups. I hope this helps someone else, too.
CherokeeWill
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