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Discussion Starter · #1 ·
I was wondering if anyone else has experienced this problem as it took my by surprised to say the least:

This past weekend I parked my SRT8 on a snow covered driveway with a fairly steep grade. I was next to a Jetta and Outback for reference. I pulled the e-brake as far as possible and put the jeep in park. As I was getting out the driver's door the vehicle began to slide backwards and the wheels were making jerky quarter turns backwards as well. It slid about 20 feet backwards into the road. I'm confused as to why the wheels were rotating backwards down the hill if I was in park with the e-brake engaged. I've got a new set of snow tires and pulled into the driveway at the same time as the Jetta which didn't move an inch.

Coincidently I was watching a repeat of Top Gear on BBC yesterday and saw a similar thing happen to a BMW X6M on a wet grass hill.

All in all it was a pretty embarrassing experience to watch my Jeep slip down my buddy's driveway while his Jetta didn't flinch.

Any idea why this would have happened?

Thanks
 

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I guess traction control is truly never off.





































































j/k

I wonder if the wheel movement is because of the open diffs?
 

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Sounds like a recall if you ask me. Once in park with the e-brake engaged the car should not move.
 

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Discussion Starter · #5 ·
That was my thought too. It was scarry as hell and the kids had to dive out of the way. The front wheels were rotating backwards in a jerking motion as the Jeep slid. The only thing I don't get is that the X6M did the same thing on Top Gear (BBC). Both vehicles are full time AWD. But when in park I have always thought a vehicle's wheels shouldn't rotate....
 

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The jeep is not in AWD when its off. the TC motor engages and disengages with the turn of the key. We are not true AWD. And i believe the E brake only locks up the back wheels. at least thats how my older grand cherokee is. could be wrong on these. So that would explain the front wheels turning/jerking. Jack your jeep up with the E brake on and you can prolly turn your front wheels.

That was my thought too. It was scarry as hell and the kids had to dive out of the way. The front wheels were rotating backwards in a jerking motion as the Jeep slid. The only thing I don't get is that the X6M did the same thing on Top Gear (BBC). Both vehicles are full time AWD. But when in park I have always thought a vehicle's wheels shouldn't rotate....
 

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That guy..
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I dont think it matters what kind of set up you have, if your parked on a slick hill. Its more than likely going to slide backwards..

And why his didnt move is probably the difference between 6,000 pound truck and 3500 pound car..

MY full size dodge ram slid down my driveway once.. It was on ice..
 

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The Traveler
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Even on level ground in park a vehicle can be rocked back and fourth a bit. The wheels rotate a little back and fourth in park. The ebrake is only the rears. So, IMO if everything was working properly the rears shouldn't have spun at all, but the fronts could do the 1/4 rotate/jerky motion.

If a cars on snow/ice on a steep hill it can slide down. Gravity wants to pull it down and if there isn't enough static friction between wheels and ground, the jeep will slide down. Plus the jeep has more mass. It's all about surface area, coefficients of friction, gravity, and mass. The ole physics and free body diagrams lol.


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PWR - Boosted & Stroked
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Yeh in my cases its only on snow/ice on the inclined driveway. The neon will slide down also but you have to give it a good push to get it going. The Jeeps are just heavy enough & the driveway is just steep enough.

Jim
 

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Discussion Starter · #13 ·
Thanks.

So I'm clear. The reason the fronts were jerking backwards is that the park pin is most likely broken. My assumption is that this isn't a cheap fix and I should just try to park on flat surfaces or low incline's with the e-brake pulled.

Has anyone else replaced a park pin? What would I be looking at for cost?

Thanks,
Sean
 

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The Traveler
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Thanks.

So I'm clear. The reason the fronts were jerking backwards is that the park pin is most likely broken. My assumption is that this isn't a cheap fix and I should just try to park on flat surfaces or low incline's with the e-brake pulled.

Has anyone else replaced a park pin? What would I be looking at for cost?

Thanks,
Sean
I doubt the park pin is broke, sounds like it's working. Just go park on a steep hill that's clear of snow and ice and put it in park with no e brake. I'm betting it'll stay put just fine.
 

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The e-brake will completely lock the back wheels. It uses a separate small caliper in the back and once engaged completely locks the pads against the rotor. No way the back wheels will rotate at all. The front will rotate back and forth some from the driveline slack.
 

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I agree with Mongoose. I highly doubt the pin is broken (you'd have probably figured that out long before this). Your vehicle is much heavier than the VW & as such is going to have a greater tendency to slide. I've had mine slip on steep driveways in Whistler as well. Just the nature of the beast. Just be careful where you park it.
 

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Considering he has some fat snow tires on the truck, I don't see this happening given we've seen a member's (can't remember username) blacked-out ride in California climbing a very steep mountain-side hill through 2 feet of snow.

I think the back wheels would be able to grip the snow enough with both wheels locked to stop the sliding of the vehicle. I dunno, but something just smells wrong?
 

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Climbing a hill and parking on 1 are 2 completely different things with 3 tons of fun.

It wasn't until the heat and pressure from me parking on the snow turned it into ice under my tires in my driveway. It is possible given the right conditions.
 
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