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Automatic Transmissions when in Park

2.9K views 11 replies 8 participants last post by  Tachyon  
#1 ·
I have a quick question about automatic transmissions when the vehicle is in PARK. What kind of state are they in and by that I mean, are there any gears engaged at all?

The reason I ask is, my dad was visiting over the weekend and one day when I went to pick him up at his hotel, we noticed the front tires of his 2013 Ford Expedition were up on TOP of the concrete parking block. Upon further inspection, we found his rear bumper was messed up. Fortunately, no other damamage, unless the transmission is messed up, which is what I am trying to figure out. He went back into the hotel and talked to the front desk and sure enough a drunk driver had come through the night before. The hotel called the cops after it happened and my dad called the cops that morning and sergeant showed up in less than 10 minutes to take a statement and give my dad the case number. The drunk asshat had already been arrested.

So, my question is, should my dad be worried about the transmission? He drove it home the next day (3 hours) and said it did fine. I am curious what is going on inside an automatic transmission when it is in park. His truck was pushed with enough force to get it up on top of the concrete parking block. Does it hurt an automatic transmission to roll when in park?
 
#2 ·
While in park there is a prawl that locks the tranny/drivetrain in place if in park the wheels wont roll when moved, but if the wheels were forced to move it may have damaged the prawl but it wouldn't effect any other part of the tranny.
 
#3 ·
being as it was the front wheels pushed up on the block, they should have rolled. on rear wheel drive vehcials ( or 4x4s in rear wheel) the park position only locks the rear wheels. the rear wheels may have just slide on the ground.

he would know if the pawl was broken, because the ford would not stay in one place.

someone else correct me if im wrong.

Alex
 
#6 ·
The parking pawl is very strong so its probable that as was said the rear tires were pushed and the fronts rolled. A telltale would be rubber marks on the front of the tire but that is moot now. No gears would be hurt but if the pawl was damaged a part of it would have been in the trans and making some noise. It does not sound like it and the old man should be fine.
 
#8 ·
A little update: the Expedition is in the shop and the drunk guy's insurance is covering all the repairs. My dad and the mechanic both think the transmission is OK so that is good. He ended up with a Hyundai Veloster as a rental, LOL.
 
#9 ·
In try to stay on subject. I have a 90 k1500 4l60e. When I start the truck in park I cannot get it to change gears. When I move it to the first key point. And put the truck in neutral, I can start the truck then move the shifter lever to what I need. Is there some kind of safety interlock that is preventing me from starting in park then moving to a desired gear?

Thanks for any help.
Chester's
 
#10 ·
Sorry that was a 1996 k1500 with a 4l60e.
 
#11 ·
Yes, there is a safety interlock that prevents the tranny from moving out of park while the engine is running. There are two conditions; The brakes have to be applied, and the ignition switch has to be in the run position. Three things can cause problems like yours; a worn ignition switch, bad wires or connectors from switch, brake pedal, tranny, or you forgot to put your foot on the brake pedal. :) As far as the switch is concerned, it may not be making full contact when returning to Run from Start, and may need replacement, or simply a little jiggling of the key. Just moving the switch to run without starting while your foot is on the brake will release the safety interlock. The factory does this so vehicles can be prepped for towing. This seems to be working because you said you can move the stick when you do this. This makes me suspect the ignition switch.
 
#12 ·
Yeah, I think you'd skid the tires before you'd break the parking pawl. However, the rest of the drivetrain can suffer damage. Meaning u-joints and diff. I'm pretty sure the Expedition has a two piece driveshaft so that's that many more u-joints to worry about.
Since it's an insurance claim, I'd have it all inspected, just to be sure. Otherwise, if it drives and parks on a hill OK, it's probably fine. ;')
Hope they nail the drunken asshat!