Help needed with mysterious stalling issue

[wvaughn2]

Update!

Ok, so first I went on Ebay, bought a 2nd hand Mopar Brake Booster for $50 shipped from a TJ of a newer year and that had half the miles "my" TJ has and installed it. It had the same warped diaphragm and therefor the same vacuum leak and kept stalling upon idle with the brake pedal depressed. The good thing was the Ebay seller I bought through offered a money back guarantee if the product did not function. So I got my refund instantly and they didn't even want the product returned so I tossed it out.

Then, I went ahead and bought a fresh Mopar Brake Booster from the factory for $250 shipped, and just installed it this morning.
My stalling issue has gone away! I ran it through all of the 3 scenarios that made it stall before, and it did not stall out at all.

I am so very relieved right now, and I would love to thank the Forum here and everyone that schooled me along the way.
Thanks forum and thank you members, much appreciated!

Now I just need to figure out my leaky Throttle and TPS, and i'll be a happier camper.

New User here- Question for EJD or Jerry Bransford (as I have seen him comment in several trans related threads). I am having a similar issue as EJD with by '01 automatic and stalling at idle or when stopping. However, mine does fine if I drop it to neutral when stopping, which makes me think it is more a trans or torque converter issue rather than a brake vacuum.

Basically it starts and runs fine, but when under load in 1st when cold, or when stopping hard (typically from a higher gear) it chokes down and sometimes out. Trans sometimes slips from a stop or between 1st and 2nd (again, usually when cold). Revving up the rpm at start , or dropping to N at a stop seems to keep it running. Realize that is a lot of vague issues, but should I start with a trans flush? Some mechanic friends recommended trying to disable the torque converter lock in to see if that lock was what was choking it out. Thoughts?

 

[wvaughn2]

Nothing could be more untrue than that old wive's tale.

If a transmission coincidentally failed after its ATF was changed, two likely scenarios are at play here... 1) The ATF was changed out of desperation, the transmission was not shifting properly so it was already in bad shape to begin with. 2) The transmission was about to fail anyway.

Jerry, replying for you to see my add on question below. Thanks.

 

[Jerry Bransford]

Disabling the torque converter lockup circuit would be a good test for that issue. It's the rear most connector on the driver's side of the transmission. If it's not that I'd guess there's a problem inside the torque converter.

Edit: please confirm what you are describing as stalling. Could you actually mean the transmission is slipping so the engine revs but the Jeep doesn't move? If so that typically indicates that the ATF level is too low. Check its ATF level only while the transmission is in Neutral and while the engine is running.

 

[EJD]

New User here- Question for EJD or Jerry Bransford (as I have seen him comment in several trans related threads). I am having a similar issue as EJD with by '01 automatic and stalling at idle or when stopping. However, mine does fine if I drop it to neutral when stopping, which makes me think it is more a trans or torque converter issue rather than a brake vacuum.

Basically it starts and runs fine, but when under load in 1st when cold, or when stopping hard (typically from a higher gear) it chokes down and sometimes out. Trans sometimes slips from a stop or between 1st and 2nd (again, usually when cold). Revving up the rpm at start , or dropping to N at a stop seems to keep it running. Realize that is a lot of vague issues, but should I start with a trans flush? Some mechanic friends recommended trying to disable the torque converter lock in to see if that lock was what was choking it out. Thoughts?

It sounds like you have a couple separate issues. You need to start with checking your ATF level and see how low your fluid is. There is a very specific way of checking the accurate fluid level. The Jeep must be running, warmed up, and in neutral. You can also run through all the gears then back to neutral, then check the fluid on the dipstick. If it is low, which I suspect it is, add appropriate fluid and your slipping issue should instantly go away.

Question: Can you stall it out on your own if you try to by really pressing the brake pedal?

For me, I could start my Jeep and back out of my driveway laying on the brake and it would/could stall. Then I disconnected the brake booster hose and plugged it, and repeated the driveway thing I could not stall it out. That kind of implies that the brake booster was the issue, I replaced it and everything is perfect since. (Thats just an example of me trying to bypass the brake booster). Point is, if you can press the brake pedal to the point that you can stall it out by doing so, it is definitely your brake boosters diaphragm flexing and creating the vacuum leak which is causing the stall while the brake pedal is pressed.

 

[Meri123]

Ok, so i've had a few issues stalling lately (mainly while driving) and I feel I have actually corrected the "while driving" issues by replacing old parts and some great insight from the forum, i'm wondering if my current stalling issue is more specific now and if any of you have any ideas or suggestions on this since I feel like I can narrow it down to 3 specific scenarios that I have stalled in.

1. Going from reverse into drive. Just about every time on a cold start I shift from park into reverse, back up, depress and hold the brake pedal...the moment it is shifted into drive (a sputter stall occurs). I do not even have to let go of the brakes before it stalls, and if I do the whole motion quickly and hit the gas pedal fast before or as its stalling it will stay alive and actually drive forward without totally stalling...but its weird to have to do that. Lol.

2. While idling at a red light. Brake pedal depressed, and after a minute or so it feels like it just chokes and stalls, but always starts right back up. If I pull up to a red light and shift into "park" at the stop light instead of holding the brakes, it does NOT stall out. Interesting...right? I notice I idle higher while in park vs in drive.

3. Making a hard stop. Pulled up to a crossroad a little hot once and realized there was a stop sign. No skidding but it did stall out when I came to a full stop there...

The common denominator is the brakes in all scenarios. So I'm curious to know if there is any connection between the hitting or holding the brakes and stalling that anyone knows of?

Please reply if anything seems to make sense as to what is going on here. I am determined to figure this stalling thing out and I know of at least one other forum member that is having the same issue going on too.

Thank you in advance!

Did you ever figure out this issue? I’m having the same exact issues and I’ve spent over 2,000 dollars in repairs that have not solved this issue. But our issues are identical. Ive taken it to Jeep 3 times and they cannot figure it out either. It’s been 3 months!

 

[ac_]

Did you ever figure out this issue? I’m having the same exact issues and I’ve spent over 2,000 dollars in repairs that have not solved this issue. But our issues are identical. Ive taken it to Jeep 3 times and they cannot figure it out either. It’s been 3 months!

If I read it correctly it looks like a new brake booster fixed his issue, but if you put a new brake booster on and it is still an issue read @Jerry Bransford's response a couple up. A stuck lockup converter could possibly do the same thing. Test it the way he suggests.