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Shutting off sporadically at stop, transmission?

Hello,

I have a 2006 Jeep Commander 4.7 65th anniversary edition with about 105k.

So I have been having intermittent stalling when at stops—specifically braking. This has been developing/happening over the past 3-4 months. Did some research and found that it may be low trans fluid causing this—turns out I was actually a quart low on fluid. Took it out again with the proper level and brakes hard (which before caused it to stall) and could not get it to happen.

It was relatively problem free for a while—maybe a bit of strange shifting (or just my head being paranoid). But the problem has surfaced again. It seems to be moreso when when backing up and braking—especially when first starting the car. I can’t really control when it happens now as I could before.

When shifting into drive or reverse, the RPMS dip a bit below 1k. Sometimes they pulse at stops signs as well. Sometimes the rpm lowers slowly at a stop and it stalls that way.

The only errors I’ve had is a SERVICE 4 WHEEL DRIVE notification on the dash, which has been there for 5 months. I have not had that looked at, though 4wd low does not work.

I’ve done quite a bit of research, and seen multiple things it may be, but nothing I can seemingly test easily. Any help is appreciated!

Bummer! … Did you have a question?

Sorry, I am technically challenged on forums apparently!

So I have been having intermittent stalling when at stops—specifically braking. This has been developing/happening over the past 3-4 months. Did some research and found that it may be low trans fluid causing this—turns out I was actually a quart low on fluid. Took it out again with the proper level and brakes hard (which before caused it to stall) and could not get it to happen.

It was relatively problem free for a while—maybe a bit of strange shifting (or just my head being paranoid). But the problem has surfaced again. It seems to be moreso when when backing up and braking—especially when first starting the car. I can’t really control when it happens now as I could before.

When shifting into drive or reverse, the RPMS dip a bit below 1k. Sometimes they pulse at stops signs as well. Sometimes the rpm lowers slowly at a stop and it stalls that way.

The only errors I’ve had is a SERVICE 4 WHEEL DRIVE notification on the dash, which has been there for 5 months. I have not had that looked at, though 4wd low does not work.

I’ve done quite a bit of research, and seen multiple things it may be, but nothing I can seemingly test easily. Any help is appreciated!

You didn’t say if you’ve checked the trans fluid once the problem cropped up again. Seems if a quart low caused it before, it would again. Have you checked the transfer case fluid levels? That is the place to start.

That T-case has a design flaw that allows a thrust shim to wear a pinhole in the back of the T-case where oil will leak out. And there is only 2 quarts IN it so it can be pretty serious in 5 months. More likely the switch, the encoder or the shift actuator in that order.

I would think a good starting point would be taking this vehicle into a qualified shop for a diagnosis as to what’s causing the light.

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I did check it just the other day when up to temp—it read within the proper levels.

I did not check the T-case fluid, could this be the main culprit to this? I will check it and refill it if necessary.

Are the components you’re referencing on the T-case, or are those on the transmission?

Stalling during/after braking ideas

  • idle rpm incorrect for some reason, possibly a faulty idle air control gadget or a problem with an electronic throttle body.
  • brake booster has sprung a vacuum leak
  • engine is running poorly due to deferred routine maintenance
  • fuel pressure, fuel injector or compression problem

Besides checking for diagnostic codes I’d probably start w/testing the vacuum booster for a vacuum leak and measuring fuel trims. Both are easy for a shop to do.

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Agree with George. I fail to see how the transmission would cause the engine to stall, other than the torque converter failing to unlock.

I did change the idle air control valve as I at first expected that to be one of the most likely problems.

My thoughts on it being transmission related is the direct cause and effect relationship between the low fluid level and how bringing that back up to the proper level helped immensely. See I had a trans fluid change done in about August of last year, and I believe they at that time shorted me one quart (there are apparently two different transmissions for my car, one holds a quart more than the other).

I suspected a possibility of running this low for (maybe) 3-4 months could have caused something to wear in the transmission–maybe even the torque converter?

I don’t think so… Far worse things like very bad noises and locked up driveline as the T-case fails internally from lack of lube.

All on the T-case.

Agree with @George_San_Jose1, though. Seems more like a low-idle condition problem. Dirty throttle body, bad IAC, that sort of thing.

So I cleaned the throttle body, and MAF today. Took it out for a quick drive with nothing too out of the ordinary. I will drive it more and see though this this problem seems sporadic.

One thing that I noticed before and still is present is that, when I shift from park to drive—or moreso to reverse—the rpms dip; sometimes to the point of almost stalling. I took a video of this happening and will attach it.

My truck has an automatic, and when I shift from P to D the rpms decrease too, even when everything is working correctly. If the engine isn’t running properly, for example a vacuum leak causing it to run lean, then it may idle so low it will stall when shifting from P to D. That’s not a transmission problem, it’s an engine problem. In my truck’s case anyway, not an uncommon thing at all. Not saying your problem couldn’t be the transmission, that’s definitely possible, but until you’ve done the testing suggested, unlikely.

Ah, but would they have the same intoxicating aroma of unburned fuel from 2 1/4" tailpipes?

So I’ve been driving it for a bit. Now the only time it stalls is when;

It’s a cold start (been sitting)
I shift into reverse (once in a while drive)
I let off brake and do not press on gas
Stalls

The rpms go wacky and it dies. Only on cold starts, basically everytime from park > reverse >let foot off brake and coast > stalls