Disobedient manual downshift
01-10-2016, 10:26 PM
#1
JK Newbie
Thread Starter
Disobedient manual downshift
I have a 2014 JKU with auto transmission.
Recently when I push the lever left to downshift, it has started ignoring me and staying in D; sometimes it will do what it's told and downshift but go straight all the way down to 1 instead of 2 or 3; when I do persuade it to limit to 2nd gear it often drops back to D again and won't be told to downshift. Sometimes cycling through N/2wd/4h/4l, ignition off and on seems to fix it; sometimes not.
A mechanic told me I have a Mercedes auto transmission containing a self-protecting feature that won't engage a low gear that would cause damage; this might be kicking in due to overheating or excessive driveline strain. However -- this also happens at low speeds on the road, not just when I'm pounding it.
Any ideas what's going on with the electronic range selection?
Recently when I push the lever left to downshift, it has started ignoring me and staying in D; sometimes it will do what it's told and downshift but go straight all the way down to 1 instead of 2 or 3; when I do persuade it to limit to 2nd gear it often drops back to D again and won't be told to downshift. Sometimes cycling through N/2wd/4h/4l, ignition off and on seems to fix it; sometimes not.
A mechanic told me I have a Mercedes auto transmission containing a self-protecting feature that won't engage a low gear that would cause damage; this might be kicking in due to overheating or excessive driveline strain. However -- this also happens at low speeds on the road, not just when I'm pounding it.
Any ideas what's going on with the electronic range selection?
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daverz (02-13-2021)
01-11-2016, 07:44 PM
#3
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02-13-2021, 07:59 PM
#5
HELP! HELP! HELP! I too have this same problem and would love to hear a fix if anyone figures it out. I have had mine to dealer, changed TCM, reprogrammed, no codes.
I am convinced I have a defective transmission. It always happens under a load climbing a long hill. I cannot tow anything. Never have been able too. I cant pull a small utility trailer uphill, let alone a small travel trailer. I've talked to others who pull long hills with loads at 70mph. My jeep is strictly that, only used to jeep. Worthless for anything else. Frustrates me to the point I haven't driven it in months. Not only is it frustrating, it's dangerous. Everytime I hit a long grade and downshift it manually, it upshifts on its own. RPMs drop to the point of a lug in 5th gear. Can't get it to downshift to save the power band, so I work my way to the emergency lane and stop. Start driving again and make it through the gears for a short distance and here we go again.
Sorry for the long post, but I don't know what else to try.
I am convinced I have a defective transmission. It always happens under a load climbing a long hill. I cannot tow anything. Never have been able too. I cant pull a small utility trailer uphill, let alone a small travel trailer. I've talked to others who pull long hills with loads at 70mph. My jeep is strictly that, only used to jeep. Worthless for anything else. Frustrates me to the point I haven't driven it in months. Not only is it frustrating, it's dangerous. Everytime I hit a long grade and downshift it manually, it upshifts on its own. RPMs drop to the point of a lug in 5th gear. Can't get it to downshift to save the power band, so I work my way to the emergency lane and stop. Start driving again and make it through the gears for a short distance and here we go again.
Sorry for the long post, but I don't know what else to try.
02-14-2021, 08:30 AM
#7
Super Moderator
Are you sure the manual shift down switch is activating? If it under warranty let the dealer figure it out. Reason I ask this is with my engine/tranny conversion I used the 2012 Jeep auto shifter and those switches are flimsy at best and I notice I have to clean them out a lot with dust and cabin lint getting in.
