Don't think you can have it downshift into 1st at highway speeds, but if you bump into 'manual' mode it will stay in first if you slow down enough and then start accelerating.

 

I can assure you that you werent doing 60 mph in 1st gear.

 

Beth1949,
First off, the engine ECM and transmission TCM, (transmission control module) all work together for a long running, smooth operating engine/transmission relationship, for many, many miles. I assure you that the engineers at FCA and, any engineer at any other manufacturer, also has designed automatic protection against HUMAN ERROR.

The way your system is designed is this. If you're presently driving your automatic at freeway speed, say, around 60-65 mph, and you're in "D", you'll already be in 5th gear. If you bump that shifter to the left one time, you'll automatically enter into the manual shift mode.

When you do that, you'll see "4th" in the dash window. At that freeway speed, the engine and transmission controls WILL allow for that kind of downshift as there will be no detrimental effects. Your engine will only be running at a higher than needed RPM, that's all. But, the system will NOT ALLOW for you to bump it all the way down to 1st gear while at that freeway speed. It (the engine ECM and transmission controls know all this stuff waaaaaay in advance of any human mis-guided input)

Now, on the other side of the coin, there is something else that will happen. If you've manually shifted in to 4th as stated above, yes, it will enter 4th. But, if you do nothing else with that shifter and you come to a stop, the shifting criteria is STILL IN THE MANUAL MODE. But, even though you shifted into 4th, by coming to a stop, the transmission will automatically shift to 1st, in preparation for the next take off.

But, because you'd put it in the manual mode, it will take off in 1st, AND NOT UP SHIFT TO THE NEXT NEEDED GEARS! It will stay in 1st gear, no matter how long and hard you accelerate.

To get that shifter out of the manual mode, simply push and hold it to the right, for around 1.5 - 2 seconds and, you'll see the circled "D" appear in the dash window, indicating that you are now in the fully automatic mode. Just remember, no matter what gear you're in, at just about any speed, if you bump that shifter into the manual mode, it remains there and in that mode, 'till you take it out of it, manually. Hope this clears some questions up.
Scott

 

Beth1949,

First off, the engine ECM and transmission TCM, (transmission control module) all work together for a long running, smooth operating engine/transmission relationship, for many, many miles. I assure you that the engineers at FCA and, any engineer at any other manufacturer, also has designed automatic protection against HUMAN ERROR.



The way your system is designed is this. If you're presently driving your automatic at freeway speed, say, around 60-65 mph, and you're in "D", you'll already be in 5th gear. If you bump that shifter to the left one time, you'll automatically enter into the manual shift mode.



When you do that, you'll see "4th" in the dash window. At that freeway speed, the engine and transmission controls WILL allow for that kind of downshift as there will be no detrimental effects. Your engine will only be running at a higher than needed RPM, that's all. But, the system will NOT ALLOW for you to bump it all the way down to 1st gear while at that freeway speed. It (the engine ECM and transmission controls know all this stuff waaaaaay in advance of any human mis-guided input)



Now, on the other side of the coin, there is something else that will happen. If you've manually shifted in to 4th as stated above, yes, it will enter 4th. But, if you do nothing else with that shifter and you come to a stop, the shifting criteria is STILL IN THE MANUAL MODE. But, even though you shifted into 4th, by coming to a stop, the transmission will automatically shift to 1st, in preparation for the next take off.



But, because you'd put it in the manual mode, it will take off in 1st, AND NOT UP SHIFT TO THE NEXT NEEDED GEARS! It will stay in 1st gear, no matter how long and hard you accelerate.



To get that shifter out of the manual mode, simply push and hold it to the right, for around 1.5 - 2 seconds and, you'll see the circled "D" appear in the dash window, indicating that you are now in the fully automatic mode. Just remember, no matter what gear you're in, at just about any speed, if you bump that shifter into the manual mode, it remains there and in that mode, 'till you take it out of it, manually. Hope this clears some questions up.

Scott

Mostly correct with the one exception being 2012 automatics. The shift selector effectively sets your top gear. Doing what you describe and coming to a stop, then starting again, the trans will shift normally up to 4th gear. Downshift to 3rd and stop and you will start in first and shift normally up to third.




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I appreciate all the advice. But when this happens, I don't see 4th in the dash window. I see D1 and it makes quite a noise. Louder than just downshifting 1 gear (5th to 4th).

Is this perhaps not normal and in need of service? I am at least glad to know that human error has been taken into account since they have made it WAY too easy to accidently bump the gearshift and inadvertently change gears.

 

It's going to downshift, but its not going to downshift to 1st. Likely you were in 2nd or 3rd.

If you were in 1st you would have either destroyed your transmission or motor. If your driveshafts didnt explode first. And you probably would have crashed.

 

Thanks - Nothing exploded and I didn't crash, so guess Everything is OK.

 

Same Problem

Hi Beth, I have been having the same problem with my 2015 wrangler unlimited for a few weeks now.

I have never had any issues with the car in the past, and this is seriously driving me nuts. My boyfriend thought I was making it up until it happened when he was driving last weekend.

I can be driving uphill, flat, highway, 10 mpg, 60mph - does not matter.
Sometimes when I accelerate, and it randomly shifts into D1. I do not touch the gear shift. No changes on my part other at all, other than accelerating. The RMPs shoot way up, it flashes D1 on my dash, makes a horrible noise, and I have to shift manually into N then back into D to fix it.
My car has felt a little "revvy" (if that makes sense, lol) to me recently too. Feels like it is idling at higher RPMs than usual, and I'm very hesitant to accelerate because it isn't shifting properly.

Last time it did this (a few days ago), my check engine light when on. I took it into a dealer today for a checkup, and they found absolutely nothing wrong.

Anyone have any ideas?? Or are we crazy?

 

Cummins, yes the 12's were nice with that feature, I had to get used to my 2016 last year after trading in my 2012. I wonder why this was "upgraded" in the later years?

 

My best guess is to have a single transmission program for all vehicles using the same transmission. If the majority of vehicles make sense to have a "full manual" mode maybe the JK got the short end of the stick.

Otherwise, I really don't know.


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HPTuners can change make the post 12s behave like the 12s. The parameter is called "Auto Upshift", and is disabled in the stock sample '13 calibration file I'm fooling with. Interesting, I don't see it in the '16 sample calibration, but I don't trust the file I have.

Mark

 

That might be something worth me looking into, thanks!