PanteraRosa

Hey Everyone,
I'm new here but I've previously found so much outstanding help on this forum that I decided to join.

I'm having a re-occuring issue with my tranny that I need some help identifying. It either shifts too soon into 2nd gear or waits until the engine revs rather high and then when I ease off on the gas it shifts. Someone told me it could possibly be a solenoid...I'm hoping it's something that simple.

When I first got it (10,000+ mi ago) it did the same thing but wouldn't shift at all, so I took it to a tranny specialist and he flushed it and cleaned the NSS. It ran fine for almost a year and just now it's started doing it again....except of course it does still shift, just a bit roughly.
BTW it's a 96 cherokee with IL6 cyl 4.0 automatic tranny

VTJeep

well, one of the first things i think i learned here was how vital the fluids are. so, check and/or flush all the ones that look low/bad... if they are really low/empty, then maybe a gasket or seal is to blame... if all fluids are good, then possibly your kick down cable needs adjusting, or your TPS (throttle position sensor) or IAC valve (idle air control) is bad. generally something of this nature is going to throw a CEL (check engine light) i had a problem for about 5 months and for the first time last week it actually threw a code; the o2 sensors were to blame, specifically the downstream o2 sensor. w/ the new ones it runs great. anyways... does it start fine? run fine? start in N? anything else you can can say is good.

DaddyCat

kick down cable adjustment is free and easy but may not be the cure for your problem (but it is free!)
https://www.cherokeeforum.com/f2/free-quick-fix-41821/

Have you checked the ATF (auto tranny fluid)... after a warm up drive, on level ground, engine running, in netural, parking brake on?

Possibly a solenoid, dirty tranny screen/filter or the TPS (throttle position sensor)

do the free stuff first, kick down cable, check the ATF level. The TPS can be tested if those 1st two don't help.

PanteraRosa

Wow, quick replies! Thanks a lot for the suggestions. First off, CEL is not thrown and I JUST replaced the downstream o2 sensor today, haha...I checked my tranny fluid level and it wasn't too bad (yes, in N, parking brake after a brief drive) but I added the LUCAS additive that's supposed to help shifting and fill in leaks. But even afterward the odd shifting persisted (maybe it needs some time to sink in).
It starts fine and runs great, the things a gem other than this, lol.
I'll have to check out the kickdown cable, one thing I noticed when shifting into 1-2 the lights on the display where my shifter is turn off...I dunno it was just weird. I'm definitely going to check this out more tomorrow as the problem seems to get more and more serious. I have recently replaced the CPS next to the flywheel but I don't know that that would be related at all.
I'll have to check the TPS with my meter tomorrow.
The thing only has 128k on it so I'm not assuming it's a major problem.

PanteraRosa

Ok, so I checked the ATF, and adjusted the kick down cable and both were fine/didn't change. The TPS however seems suspicious.
I hope I've got the right sensor, it's on the opposite side of the TB from where the kick down cable is and when I backprobed it I got a steady reading of around 5.1-2 volts, but when I opened and closed the watchamacallit it didn't alter the voltage...I'm suspecting this is to blame but it didn't throw the CEL.
My buddy has one of those computers to plug into it so I'm going to do that and see what the readings are like and if bad, replace the sensor unless there's a way to just adjust it.

freegdr

check for codes anyway just because its not lit does not mean there is not a prob

freegdr

http://jeep-xj.info/HowtoECUcodes.htm

PanteraRosa

Yah, I just did check the codes, nothing showed. I adjusted the kick down cable and it *seems* to have helped...it shifts now but I'm still a little doubtful.