RUNAWAY KJ! Should I be worried?

GoodAScoolwhip · **Posted:** Sun Apr 25, 2010 7:28 pm

Very scary thing happened this morning. I'll give you the details in a moment, but has any shifted their libby from PARK into REVERSE and have the thing take off - no matter how hard you push the brake pedal? I nearly lost my KJ in a ravine this morning! :furious:

Here's what I did, and maybe someone here can tell me what (if anything) I did wrong, and whether I need to contact Chrysler to file a complaint for faulty equipment.

My Jeep: 3.7L V6 automatic. I was in 4LO at the time.

1.) A buddy of mine had his 2wd chevy down by a creek and couldn't climb back out. The tow strap I had wasn't long enough for me to get up on the flat ground to pull him, so I was on the same steep hill, trying to pull him up. The earth was very loose, so all we did was spin and dig ruts.

2.) Frustrated, I shifted to reverse and backed up a few feet to unhook the strap and try again from a different angle. I sat there on this steep hill in REVERSE, idling with my brake applied. My buddy was behind the truck, so he unhooked the strap, and went and climbed back in his cab.

3.) I shifted into PARK, but when I did, I heard a horrible whirring kind of grinding sound coming loudly from the engine. It almost sounded the way my old stick shift would sound if you tried to change gears without pushing the clutch - grinding gears while in PARK.

4.) My brain did the first thing it could think of. Since the noise wasn't there when I was in REVERSE, and the noise started when I shifted to PARK, I just shifted back in to REVERSE to make the noise go away.

5.) That was when things got ugly. My jeep barrelled down the hill in reverse as if I had popped the clutch in a stick shift. I was holding the brake pedal as hard as I could but it kept going. I smashed in to my buddy's truck, which was the only thing that stopped me from driving right off the 20ft ledge to our left.

6.) His truck had stopped me for the moment, but the jeep was still pushing! I yanked up the emergency brake, threw the shifter in to park and killed the engine. I immediately got myself and my son out of the jeep.

7.) After a few minutes of calming down, I braved myself to get back in to the jeep and shift to NEUTRAL, start the engine, and shift to DRIVE. No more wierd sounds or phantom acceleration. So, I drove back up to the road and parked while we got another vehicle to pull my buddy out.

This took place up past Payson. I drove my jeep all the way home here to Queen Creek with no more problems.

All I can say is that I'm glad that my buddy got back in his cab, and all I smashed was his truck. If he would have been standing there still, he might be dead. I can get the insurance to fix his truck. But does anyone know WTF went wrong?

Cherrie 274 · **Posted:** Sun Apr 25, 2010 7:56 pm

Grinding noise good have been 4lo not completely engaged. My Dodge trucks would make a grinding noise unless I shut it off in N ( transmission). Placed it in 4 lo restart any noise shut off. Try again.
As for the taking off part, well ...could you have pressed the gas pedal? Sorry got to throw it out there it can happen. Glad to hear that know one got hurt.

GoodAScoolwhip · **Posted:** Sun Apr 25, 2010 8:00 pm

I was already in gear, attempting to pull up the hill, spinning the tires. I stopped with the brake pedal, shifted to reverse and backed up to relieve the tension on the tow strap, and stopped again with the brake pedal. I never moved my foot from the brake pedal. I was at a complete stop while in reverse - idling in reverse. I shifted to park and never let off the brake. I shifted back to reverse with my foot still on the brake. I never moved my foot from the brake.

Valid suggestion, but no. I never hit the gas pedal. My foot never left the brake.

Cherrie 274 · **Posted:** Sun Apr 25, 2010 8:10 pm

Then be worried. Always be ready for it to happen throw it in N. I don't know if the Jeep has a Mapp sensor(think that's what it was called) but a guy hit my van one time because his was bad.He drove a Ford Bronco.It just raced by its self and he over heated his brakes and was to scared to shift to N. So he slamed into my parked piece of crap van, I was mad but glad the idiot didnt kill somebody walking by.

JL Rockies · **Posted:** Sun Apr 25, 2010 8:41 pm

mine has made grinding noises when I've put it in park with the RPMs up and in 4LO.

JeepinJarhead03 · **Posted:** Sun Apr 25, 2010 9:07 pm

with the reverse low gear ratio, plus 4-lo

if you had a fast idle when you put it in reverse, say 1100 RPM instead of the normal 650-700 RPM, it occurred because your brakes aren't strong enough to overcome that amount of torque, that would be equal to or more than half throttle forces in 2wh in drive standing on the brake, and the harder you pressed the brake the slightly higher RPM you induced due to the extra strain on that system

anytime you're experiencing a fast idle and having to work with 4lo, turn off the A/C throw it in N, kill the engine wait a few secs and restart it, it'll usually idle right back down to about 600-700

GoodAScoolwhip · **Posted:** Sun Apr 25, 2010 9:14 pm

I have to admit that I didn't notice any difference in the rpm's in all the comotion, but what you say makes sense.

but why they grinding noise in park? If it was a fast idle, then wouldn't it just sound like the engine reving up?

JeepinJarhead03 · **Posted:** Sun Apr 25, 2010 9:15 pm

the grinding noise in park? no idea unless it's some sort of torque tension related synchronization issue

JL Rockies · **Posted:** Sun Apr 25, 2010 9:36 pm

Mine does that.

tjkj2002 · **Posted:** Sun Apr 25, 2010 9:39 pm

1st you did not experience the same thing as toyota is,you still have a mechanical link between the gas pedal and throttle body.2nd when in 4low it will be very hard to overcome WOT while pressing the brakes due to the reduction the t-case gives.

Only a few things caused your WOT issue,sticking throttle cable(can happen,they rust just like anything else and it is a wear item),a sticking butterfly in the TB(carbon build up,lack of maintenance),and finally driver error(had foot on both pedals,it happens more then you think).

Anyway you look at it not Chrysler's fault,from your avatar pic I'd be blaming it on playing in the mud which is the most likely cause.

GoodAScoolwhip · **Posted:** Sun Apr 25, 2010 10:27 pm

Based on everyone's input, I'm thinking that because I was on such loose earth, that although I thought I was at a complete stop, my wheels may have still had some movement. My RPMs must have been elevated when I shifted to park. Shifting in to park and then back in to reverse with the high idle thrust my wheels with enough torque to overpower the brakes. Considering the steepness of the hill and the loosness of the soil, the laws of motion played a big role after that.

I'm guessing from everyone's post so far that I should probably stick with neutral on the transmission and using the parking brake from now on when I need to get out of the vehicle. Does that sound about right?

JeepinJarhead03 · **Posted:** Mon Apr 26, 2010 12:23 am

the parking brake often has trouble holding the vehicle on any sort of incline so be very careful doing that

if the vehicle is going to idle more than a minute or so, just put it in neutral, kill then engine then put it in park

takes about the same amt of fuel to restart it as it does to idle more than a minute or two

valvestem · **Joined:** Thu Jul 07, 2005 7:01 pm **Posts:** 222

I think JeepinJarHead has the answer, the torque overwhelmed the brakes, especially downhill. There is nothing like good torque when felt in certain situations, in your case though not good.
I mention this because I had a 1975 International Scout II with a 4 speed Trans, and a 2-speed T-Case, LO-LO was fantastic, slip it in and let out the clutch, it would go along on level ground and slight inclines without touching the gas pedal. Of course the engine would rev out at about 5MPH too.

durangotang · **Posted:** Mon Apr 26, 2010 12:46 pm

Never had any problems with the brakes holding the diesel in place in 4-Lo

Don't think torque was the issue... unless the skinny pedal was accidentally pushed.... buts that's another matter altogether... one we've all been guilty of one time or another

JeepinJarhead03 · **Posted:** Mon Apr 26, 2010 2:44 pm

Reason I am more towards the fast idle + downhill + reverse overwhelming the brakes is that i was out on the beach in rev in 4lo talking to a dude in a XJ, my idle jumped from 650 to 1100ish in a loping bad idle and it lurched backwards twice (i'm a left foot braker btw)

but i totally know what ya mean about the lo-crawl, clutch out and foot off the gas

saw a terra-low straight drive yota do a recovery without a driver like that

and i pretty much drove down the beach at 2 mph with the back gate open loading firewood in the back as i came to it and standing on the running board to navigate

wouldn't be safe on a populated beach but if you're out by yourself, lock it back in 1st gear, it's gonna have to redline before you can't run to catch up haha.. and .. im not sure that would be fast enough to out run you

curt7088 · **Posted:** Mon Apr 26, 2010 4:30 pm

maybe ur kj is christine incarnate??? just a guess... instead of a thunderbird? (wait was she a thunderbird? i dunno but even still) and she was just getting vengeful... :jester:

but i'm glad no one was hurt and even though u smashed into ur buddies truck, the damage seems to be pretty minimal... hate to hear bad stuff like that...

tommudd · **Posted:** Mon Apr 26, 2010 6:43 pm

curt7088 wrote:

maybe ur kj is christine incarnate??? just a guess... instead of a thunderbird? (wait was she a thunderbird? i dunno but even still) and she was just getting vengeful... :jester:

but i'm glad no one was hurt and even though u smashed into ur buddies truck, the damage seems to be pretty minimal... hate to hear bad stuff like that...

Not to get off track here but
Christine was a 58 Plymouth Fury not a Thunderbird
license plate number CQB-241 in the movie.
It was previously owned by Ronald LeBay before being sold to the unsuspecting guy who had major problems with her! :twisted:

OK back on track now

curt7088 · **Posted:** Mon Apr 26, 2010 9:43 pm

tommudd wrote:

curt7088 wrote:

maybe ur kj is christine incarnate??? just a guess... instead of a thunderbird? (wait was she a thunderbird? i dunno but even still) and she was just getting vengeful... :jester:

but i'm glad no one was hurt and even though u smashed into ur buddies truck, the damage seems to be pretty minimal... hate to hear bad stuff like that...

Not to get off track here but
Christine was a 58 Plymouth Fury not a Thunderbird
license plate number CQB-241 in the movie.
It was previously owned by Ronald LeBay before being sold to the unsuspecting guy who had major problems with her! :twisted:

OK back on track now

srry tom, the movie was waaaayyy before my time and i read the book when i was 14 or 15.... so yeah... so i stand corrected she was a 58 plymouth fury... not a thunderbird... thnks tom...

JeepinJarhead03 · **Posted:** Mon Apr 26, 2010 10:50 pm

dont remember what the movie was

made me think of that horrid 70s movie with the heavy breather driver who was being chased driving some 4 door sedan by a big nasty mac truck or something

been years since i saw it though

jnaut · **Posted:** Mon Apr 26, 2010 10:55 pm

Anytime your vehicle seems like it's lurching in either direction "no matter how hard you press the brake" always put the shifter in neutral.

I have had my vehicle inch forward in for low even when I was pressing the brake when going downhill, but I would imagine that if I'd have really pressed the brake hard the vehicle would have stopped, so I merely popped the shifter in neutral.

RUNAWAY KJ! Should I be worried?

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