Made a rookie mistake today

[tony72cutlass's']

back in the day we’d pull engines out of cars at the track and not chock anything. It was common to swap engines with a buddy and track for a weekend

it’s kind of amazing most (some) of us are still around

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[ProHERO]

Great insight and advice from everyone! I love all the technology and engineering in these trucks but it’s easy to get complacent thinking of how convenient it make our lives. It’s easy to blame someone or something that we thought was supposed to do something but plain and simple, I should have taken the 30 seconds to place the chocks I had 5 feet from me. As always, stay safe out there everyone!

 

[Gros Ventre]

Remember: The rear axle is an open differential. So, if the parking brake is not set, when you lifted one wheel up the transmission park feature, which kept the propeller shaft from turning, still kept it from turning... but with one free to spin the other one could spin in the opposite direction...

 

[sbi]

Glad you shared this. I would have thought the parking brake would have engaged both the front and back brakes.

+1
Would never have thought about that having never owned a 4x4 vehicle.

@OP - glad you are OK, that's the important thing. Could have ended a lot worse.

 

[ProHERO]

Remember: The rear axle is an open differential. So, if the parking brake is not set, when you lifted one wheel up the transmission park feature, which kept the propeller shaft from turning, still kept it from turning... but with one free to spin the other one could spin in the opposite direction...

Ah, now the light bulb goes off in the head. The real mystery in the back of my mind was how 3 wheels on the ground would roll in park. Makes sense since the wheel off the ground is not applying that opposite force to stop the vehicle from rolling. Thanks for the clarification!

 

[SumGuy]

So this morning I noticed a clicking noise coming from outside in the back and I immediately thought it was a rock in the tire. When I got home my jaw dropped when I saw a screw in the tire. I decided to remove the tire, replace it with the spare and get it repaired at the tire shop. There’s not many level roads where I’m at so I reversed into the garage. My garage is level except for a small lip in the front that I couldn’t clear because the truck is too big. So I lifted the truck with the jack, got the tire off and as I went to put the spare on, the truck started rolling forward. The truck rolled about 10 feet by the time I got inside to get on the brake. I was in shock and pissed that this happened because on a regular basis I do my own preventative maintenance and I’ve removed and replaced my tires several dozens of times. As I thought about what happened, I know for a fact the car was in park but I didn’t have the parking brake on which I normally do and I didn’t have chocks in the front.

After thinking about this more, shouldn’t the transmission in Park have prevented the truck from rolling? I couldn’t have accidentally left it out of park as the shifter prevents leaving the vehicle in any gear. I verified this safety feature was working and I’ve never had an issue with the transmission. I even parked in reverse on a steeper hill and once placed in park it didn’t roll.

In the end, I learned a hard lesson. It could have been a lot worse. There was very little damage except to the metal plate behind the brake rotor which I bent back to shape. Although I say it was a rookie mistake, I should have double checked the parking brake was set and used the chocks. This was completely preventable. Please everyone stay safe out there!

First, glad you’re ok. People die every year from not properly securing a lifted vehicle and not using jack stands

The parking brake only actuates the rear caliper. So you would have been in the same situation with the brake on, maybe.

wheel chocks from harbor freight are your best friend. As are some heavy jack stands. Use them always. Never trust just the jack. The hydraulics can fail suddenly at any moment.

stat safe.

 

[B-real]

I had one rear tire up and one down but I guess that one tire down wasn’t enough to overcome the forces of it rolling forward. Sad thing is I have chocks in the shelf behind where I was working on the truck. Like you said, I must have placed too much trust in the truck doing what I think it was supposed to do. I’m not aware of the metal chock. I have a jack, rods and a funnel. Maybe Ford deleted the metal chocks.

Rear axle is an open diff, meaning that at any time one of the wheels is free to spin (unless the electronic locker is engaged). This means that if you have one wheel up in the air the one on the ground would be able to rotate. Next time you swap tires, block the front wheels and then with both rear wheels in the air turn one of them, the other side will spin backwards.

Glad you shared this. I would have thought the parking brake would have engaged both the front and back brakes.

I dont know of a single vehicle where the parking brake engages both axles

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