2003 3rd-4th rpm spike

[Aceofspades]

Hey guys Wondering if anyone else had a similar issue. The jeep has a about a 200rpm spike before it goes into 4th under throttle.
I can replicate this on the fly by simply being on the highway and pressing the OD button on/off. Each time you turn it back on manually , its like something slips before the shift, or maybe the TC is unlocking/locking? Never happened before. Currently resetting the battery to see if maybe its a simple computer issue (doubtful)
It has regular pan drops, last one was end of 2018 12k miles ago
Thank you


edit this is for my 2003 42rle not the 2002

 

[tommudd]

All 3 of mine are right there when full throttle going from 3rd to 4th, no spike at all
Just hits and goes

 

[Aceofspades]

Well... only 75k now on it and the battery reset didn’t change a thing.

And Tom - What are you saying ? That your Jeeps don’t have that issue or something or am I not reading between the lines ?
Curious If it’s something I repair like a solenoid or valve body etc

 

[tommudd]

OK let me try and explain again
NO " spike " none of them do that just good hard shift

 

[Aceofspades]

Well that makes sense now. You’re just telling me it’s not normal.
Tom - I know it’s not normal but was looking to see if anyone else had something similar happen so I can get a head start on the diagnosis or repair. Thanks man !

 

[LibertyTC]

After some hwy driving when hot, pull over on level ground & while still running, & take a trans fluid dipstick reading.
My jeep likes it to be about 3/8inch of an inch above the full line.
By your description it sounds like you may have some slip/ wear coming from 3rd gear, before it goes to 4th.
Any trans shop should be able to read any stored or pending solenoid or trans codes, and then determine if the CVI are with in specs or not. (clutch volume Index)
You want some miles /history on it before doing a scan, so don't do another battery re-set before taking it in.

 

[Aceofspades]

After some hwy driving when hot, pull over on level ground & while still running, & take a trans fluid dipstick reading.
My jeep likes it to be about 3/8inch of an inch above the full line.
By your description it sounds like you may have some slip/ wear coming from 3rd gear, before it goes to 4th.
Any trans shop should be able to read any stored or pending solenoid or trans codes, and then determine if the CVI are with in specs or not. (clutch volume Index)
You want some miles /history on it before doing a scan, so don't do another battery re-set before taking it in.

Thank you. Going to drive it this up coming week and have it looked at for any codes.

 

[Aceofspades]

Unbelievable. 78k miles on the 2003 and it surges before 4th gear still. I was really hoping it was a simple fix like dropping the pan and replacing something.
Honestly it seems crazy to to dump 3k into a new transmission but....


I been trying to diagnose another issue as well. I’ll make another thread

 

[Phuc Nguyen]

Is your check engne light is on with error code P0700/0740. And at 70 mph, your engine RPM should be at 2200 on flat road, anything higher is your torque converter.
I replaced one, on my 2004 Liberty with a replacement from Autozone for $170, sold by Precision from Erie, Pennsylvania. After that, it runs like a champ.
I replaced mine via remove the engine instead of removing all lower drive train. Crazy isn't it, but it works for me.

 

[JeepJeepster]

The spike that youre describing when you have o/d off and you press the button to go back into 4th is the torque converter unlocking. If its locked, it must unlock before the transmission shifts. Thats 100% normal.

Under normal driving and just letting it shift on its own, the torque converter shouldnt be locked in 3rd. So thats normal. My 42rle shifts like junk but the rpms do not go up right before it shifts into 4th. Do you think the torque converter is locking in 3rd? I know the dodge nitro does that, I always found it odd.

The dodge nitro also does not have the unlock the torque converter in 4th option when going up a hill. It just downshifts into 3rd.

 

[Aceofspades]

Thanks for all the replies. It’s really not normal. It’s surging bad. If you drove a manual and missed your shift and hit neutral.

So it got torn down and gutted. Problem
Solved. Did I find the exact culprit ? No
The new converter is bearing-based.