Hellbound13

So all the issues that I had with my transmission got me to thinking...maybe I have faulty TPS? I mean the vehicle shudders a lot when accelerating, I get a dead spot at 1500 RPMs sometimes that requires me to mash the pedal down at which point it jumps to 3000 RPMS, and also I can feel my engine surge and buck sometimes. Are those not all symptoms of a bad TPS? Maybe this is why the replacement of the torque converter did not help in the first place..

derff96963

I don't think you have a bad TPS. Mine has done what you describe for the last 40k miles and it has never changed in any way or gotten worse. I believe its just the way it is programmed, to get better gas mileage. The engine has little power under 2500 RPM but it gets good mileage. I think they put the dead spot in there to make sure you want the power and it downshifts to third and thats why the RPM shoots up to 3000, into the power band and you accelerate away.

Mine will also buck on occasion but I have watched the RPM's when it does it and it was basically in the middle of shifting when my throttle input told it to go the other way and it bucks. All transmitions will do this if caught in the middle of a shift.

I can understand if you don't like it but the dealer can't fix it because I think it just the way the programming is. I can't say I like it either but I have gotten used to it. Everyone else I know personally that has a JK theirs shifts the exact same way that mine does.

Hellbound13

Really? You are the first to say this is normal, but I guess it certainly could be. I can't understand how they possibly sell any autos with the way it drives. Does yours have a shudder also?

derff96963

I don't understand what you mean by shudder. Mine doesn't that I know of. However the way you describe the shifting is exactly what mine does. Its also exactly what my one cousins, my aunts, and one of my coworkers does. We have all driven each others and they shift exactly the same and exactly how you describe. That is why I said I think it is programmed to be that way. A power programmer like hypertech might help this if it changes the shift points.


I don't like the way it is either but like I said I have gotten used to it and my foot knows what to do to make it shift.

Hellbound13

I do have the Hypertech and it has made a huge improvement as it has given me more power and better throttle response, however it has not cured the "issue" at 1500 nor shuddering. Let me describe it better and see if this is the same thing you are talking about..

I will driving and when I let of the gas the RPM needle will drop and rest on 1500 RPMs, when I then go to apply throttle again sometimes it will shift fine, but other times it will get "stuck" at 1500 RPMs until I push the gas pedal down much further at which point it shoots to 3000 RPMs. Is this what you experience?

aldaman

That same thing happens to my automatic JK...As an example when I am going uphill my foot will be steady on the gas pedal. The JK will be holding steady to ~2k RPM, then all of a sudden the RPM drops to 1500 then slowly to 1k with my foot still steady on the gas pedal. to overcome that, I either apply more pressure on the gas pedal (usually press it 3/4 more) or simply downshift to 2nd gear..I've driven other automatics from different vehicles & they dont have this symptom. I chalk it up to just a bad design DC built on this trans...I wished it could have been better, but for now will just have to make due until something better comes along (like a hemi swap w/a new trans )...

Hellbound13

Does yours also do the symptom described above?

ronjenx

Regarding the reluctance of the automatic to downshift when you give it more gas pedal:
I did a test the other day and found the following.
When going along with the tranny in overdrive and the T/C locked, if I slowly press the gas pedal, the tranny will seem to delay downshifting until I have given it quite a bit of pedal.
If under the same circumstances I give the pedal just a little, but more rapid push, it will downshift a lot sooner. Note that I said just a little push. I think this is significant. Also, when in cruise, it will downshift without delay when on a hill, much the way it does with a little but rapid push of the pedal.

TINMAN080

I have no symptoms like you guys are describing, 18000 miles, no level ground, it shifts on hills etc just fine. Ronjenx describes my operation perfectly when on cruise. I broke my jeep in BRISKLY-I've never lugged it around in gear, if I wanted a downshift I put the pedal to the metal and kick it down. Expecting this design of tranny to crisply shift down on light throttle ain't gonna happen- it requires some operator input. A quick jab does cause a much better shift response from this tranny than toeing the pedal down expecting it to draw the input from you. Require this tranny to shift when you want it to- you can train your foot and the transmission to do it. It will learn your driving style.....Brisk is best- use it but don't abuse itI believe the converter shudder is this tranny's way of saying''what do you want me to do''? tell it with your foot....it does work.

TINMAN080

A faulty TPS falls under the emissions part of your warranty package which is 80000 miles I do believe. A bad TPS will throw an immediate code that will not reset without a scan. If you had a bad TPS it would show the code....