My 2006 TJ with the 4.0 motor, 42rle trans and 3.73 gears was having hard shifts only when I first drove it. Then it would calm down and shift smoothly. I checked and made sure the trans fluid was full, clear and pink with no burn smell. Still did the hard shift in the morning. Then I found how many others with 2005-2006s withthe (I don't like it ) 42rle had the same issue. Finally on Saturday morning I disconnected the battery negative terminal and let it sit that way for about 1 and 1/2 hour. Hooked it up and he problem was gone. Shifted perfectly smooth, no hard shift at all. So it's been only two days, but still working like it should. So many other were correct, it isn't the trans, it's the stupid computer control things telling the Trans to stay in gear too long and then shift hard. I read that some others did the same thing I did and it lasted them about a week before theirs went back to hard shifts again. I can't afford to go hunting for a different PCM, nor would I know what I was doing. I'll see by the end of this week if it still works good or goes back to the nasty shifting. Strange I've had this Jeep for about two year now and it never had this problem until I switched from 15" rim withabout 29 or 30" tires to the Rubicon factory 16" wheels with 31" tires and got in the habit of turning off the Overdrive before I took off. Anyone think there may be a connection there? Maybe I spazzed out the computer? I would love to know what others think and did.
06 TJ 42RLE Hard Shift Fixed
- Thread starter Peter Panagakos
- Start date
Purely a guess ... but perhaps the computer is struggling with the speedo saying one thing and the rpms saying another. Switching the OD off may also be telling the computer to hold all the gears longer to make up for losing its high gear. This is one of the many reasons I prefer a stick shift. But they have been sticking computers in them too for years.
Interesting idea. I think if I ever find one again I'll get a good old military M-38 or Willy's CJ with the old T-90 trans and no Computer. Ofcourse I won't go more than 45 miles an hour.
MountaineerTom
LJ Enthusiast, Retired USAF Weapons Loader
Supporting Member
Ride of the Month Winner
Mine did it a time or two with the factory wheels and factory sized 30" tires on it before I ever switched them out.
I have a 2006 Jeep with a 42 RLE and have had some of the same problems as I've read on this post. Just wondering if the solenoid pack in the valve body is bad would I get a light or not? Shifts hard 1st to 2nd for a little while then smooths out and then everything's okay. I bought this Jeep recently with 33-in tires and a 2-in body lift. I was thinking about taking it to the trans shop and having the selenoid pack replaced but not sure if that would solve the problem?Does anyone have any thoughts on this? Thanks
Lilnuts
TJ Enthusiast
From what I understand this is a common problem with the 05-06 TJ auto tranny. It's my understanding the problem lies in the computer itself. Disconnecting the battery and resetting it will last only for a little while and the good times period get shorter and shorter.
Read about it here:
https://wranglertjforum.com/threads/05-06-pcm-issue-is-solved.21699/
Read about it here:
https://wranglertjforum.com/threads/05-06-pcm-issue-is-solved.21699/
Yup- it will be back- especially when the weather warms up. I have the exact same set up and the exact same problem. Eventually I will replace the ECU/PCM but i have lived with this for 3 years now.
Check out a new computer from @Wranglerfix - thread linked above. Your problem is absolutely the computer.
Thank you. Sounds like my pcm seen better days. I'll be ordering one from Wrangler Fix for sure. He knows what he's talking about and stands behind his product and even referred me to watch a video of somebody installing it and it worked like new.
I put in the wrangler fix last summer and have had no shifting problems since. Works perfect. Price was reasonable and customer support was excellent. For Fisher, if you have not yet, disconnect your battery for 10 to 15 minutes. Then hook it up and drive. If the hard shift is gone, it's the PCM. Disconnecting the battery will only help short term. Call Wrangler Fix , it works.
futhgar
Member
Silly question here (I apologize for reviving an old thread) - we're experiencing similar symptom with a 2004 Wrangler. I'm going to try the battery trick to see if that works. In the case the battery trick works, would that mean I should replace that PCM eventually? Thanks in advance.
I thought the PCM issues were with the 2005 and 2006 model year. What Transmission does your Jeep have? I would do the battery trick and see if your problem goes away for a while. If so, it will come back. Then I would call mark at Wrangler Fix. He will be able to advise. I put in the Wrangler Fix PCM a few years ago, and no trouble since. I highly recommend them.
Transmission is controlled by a separate computer in 04, it’s probably a different issue, but talking with Mark will help steer you in the right path.
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futhgar
Member
Thank you y'all I'll reach out. We're experiencing rough shift when we first on ride with the Jeep and after a while it smoothes out more.
Have you put a scanner on it to see if you're getting any codes? Make sure it's a scanner that can read transmission codes. Also note that the hard shift problem will not generate a CEL.
futhgar
Member
I have a bluedriver reader it supports tranmission codes and I've not gotten any transmission codes for the transmission. Just today (like 2 hours ago) I replaced the Oxygen Sensor Bank 1 / Sensor 2 and the throttle position sensor. I was getting CEL codes for those. Looks like the hardshift did go away after doing that, but I am still having this weird groan sound with no vibration, just a sound.