Hard shift to Overdrive

While driving last night, I had an hour trip driving through some traffic, and was experiencing some very strange shifting from the KJ..

It has always shifted pretty good, but while on the highway doing a lane change downshift from OD to 4th, the shift back up to overdrive once I let off and got up to speed, it had a very hard shift back into OD. It did this about 4 times, throughout the trip. On the way home I tried to replicate the issue but was not able to. It has done a shift like this before but it was rare, and I never thought too much about it.

The Jeep has 106k on it, and before I owned it, I don't think the PO ever changed out the fluid, and I got it at 70k. Early last summer roughly 15K ago I did do a pan drop, with a new filter. I checked the fluid level and its reading right where it should be, but I was starting to wonder if the dipstick reads correctly.

Has anyone had a similar issue? I am not sure if the ****** is on its way out, or something like a solenoid?

You mean shift into 3rd then back into OD? You only have a 4 speed trans with the 4th gear being OD.




You could have been experiencing the TC locking and unlocking.

Before you get all worked up and concerned, I would service the transmission with new filter & ATF+4. I do this every 35k...cause I'm that picky about having fresh fluid in there.
Obviously to remove all the old ATF it is best to have the dealer do the service cause they got the right machine for the job and it gets all the fluid out incl the torque converter that a pan drop does not do.
Often the old fluid friction modifiers will break down and simply renewal makes it shift good again!
Edit: While at the dealer they can check for transmission codes and see if there are any firmware updates as well.

tjkj2002 said:

You mean shift into 3rd then back into OD? You only have a 4 speed trans with the 4th gear being OD.


You could have been experiencing the TC locking and unlocking.

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You are correct 3rd to OD

LibertyTC said:

Before you get all worked up and concerned, I would service the transmission with new filter & ATF+4. I do this every 35k...cause I'm that picky about having fresh fluid in there.
Obviously to remove all the old ATF it is best to have the dealer do the service cause they got the right machine for the job and it gets all the fluid out incl the torque converter that a pan drop does not do.
Often the old fluid friction modifiers will break down and simply renewal makes it shift good again!
Edit: While at the dealer they can check for transmission codes and see if there are any firmware updates as well.

Click to expand...

I did check for any ****** codes with a buddys scan tool (can read specific brand vehicles, trans DTCs, probably nothing like a dealers scan tool, but nothing came up)

When I took it in last summer for the ******, the dealership warned to not do a flush, as I had no history of the trans ever being serviced and at the mileage the new fluid could "shock" the transmission causing issues, that is why I stuck with the pan drop, and filter.
I may try another pan drop this weekend, and check the magnet to see if there are any bad signs.

Has anyone ever had any issues with the dipstick not reading correctly?

^ ya I have questioned the dipstick a few times.
What I did find was that shifting was better when it was above the full mark by 1/4 of an inch, so that is where it stays on the KJ. (hot running on level ground -in Neutral)

LibertyTC said:

^ ya I have questioned the dipstick a few times.
What I did find was that shifting was better when it was above the full mark by 1/4 of an inch, so that is where it stays on the KJ. (hot running on level ground -in Neutral)

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do you mean 1/4 of an inch above the Maximum level?

Yes & keep in mind that fluid does rise on dipstick as it get hotter, so that would be after driving the KJ for 45 minutes to ensure fluid is actually Hot.

I forgot to mention that dealer is the only way to ensure completely new ATF+4.
Going to quote TJKJ from a recent post:

tjkj2002 said:

Never seen or heard of "power flushing" a trans,you will instantly blow the trans or the machine.also never seen a trans not work on new fluid but will when the old fluid is put back in(would be impossible anyways),heard that rumor long ago and asked our trans service rep(50 years on the job) and he has never seen it,heard about it but it's just a myth like once you put in synthetic oil you can't go back to dino oil.


All trans machines are fluid exchangers,never use the chemical cleaner and have it done often(every 60k at least) and change the filter(s) at least every other service you will be fine.

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In reality it is only a transmission fluid exchanger machine, and no harm will come to our beloved KJ's in this process!

I have not been able to replicate the problem, but my GF not very mechanically inclined, did ask if the fact that the Jeep was loaded and the A/C was running would have anything to do with it.

We were moving stuff and had 3 people, a pretty good loaded trunk and trailer hitch storage rack on the back, about 85 degrees and humid out the AC was cranked. I do notice the Jeep struggles at times accelerating with the AC on when on the highway, could that play a role on the ****** shifting?