Do 4WD front wheels lock in "Park", while in 4WD?

[P51D]

If you are in 4WD, let's say backing the boat in, and then you put the vehicle in "Park", do the front wheels "lock"? That is, do they lock in "Park" similar to how the drive wheels lock in "Park" on 2WD vehicles?<br /><br />Or another way to ask it: Let's say you end up with the rear wheels in the water, on the ramp slime, and the rears have no traction (unbeknownst to you). Would the front wheels help save the day and keep you from sliding backwards, if you put it in Park and took your foot off the brake? I'm assuming, of course, the fronts have sufficient traction.<br /><br />The vehicle in my case is a 2002 4WD TrailBlazer, auto trans. And I'm talking about having it in "4WD", not the "Automatic 4WD" that is 2WD until it senses slippage. THANKS

 

[cm5408]

Re: Do 4WD front wheels lock in "Park", while in 4WD?

well lets think this one out. Park is acutally in your transmission and the transfercase is after your transmission. when in 2wd and you put it in park, only your back driveshaft is in park. when you engage 4wd through your transfercase, it locks the front drive shaft to the rear drive shaft via chain and they will work together at the same time. when you put the transmission in park neither drive shaft will be able to move.

 

[Silvertip]

Re: Do 4WD front wheels lock in "Park", while in 4WD?

Another way to look at it is if you are in 4WD and under power, all four wheels pull -- therefore the same applies in park since PARK is in the tranny -- not the wheels. By the way, you should always set the emergency brake first, then put the truck in park. When pulling out, shift out of park first, then release the brake. The bang you hear when pulling the lever out of park is the parking pawl inside the tranny. It doesn't like that and repeated abuse by not using the parking brake will eventually round off the teeth on the pawl and your vehicle might go for deep water swim some day. On a very steep ramps it is also possible for so much pressure to be put on the pawl that you won't be able to shift out of park. It then takes a slight tug from another truck to release some the tension.

 

[nitedmn]

Re: Do 4WD front wheels lock in "Park", while in 4WD?

Originally posted by Upinsmoke:<br /> Another way to look at it is if you are in 4WD and under power, all four wheels pull -- therefore the same applies in park since PARK is in the tranny -- not the wheels. By the way, you should always set the emergency brake first, then put the truck in park. When pulling out, shift out of park first, then release the brake. The bang you hear when pulling the lever out of park is the parking pawl inside the tranny. It doesn't like that and repeated abuse by not using the parking brake will eventually round off the teeth on the pawl and your vehicle might go for deep water swim some day. On a very steep ramps it is also possible for so much pressure to be put on the pawl that you won't be able to shift out of park. It then takes a slight tug from another truck to release some the tension.

Also. It's very easy for this to break when under heavy load (like from a boat parked on a hill). If it does break then you have nothing stopping your truck from following your boat into the water. I've seen an RV up to it's roof in water because of this. (wish I had a copy of the pictures)<br /><br />Always set the parking break...

 

[P51D]

Re: Do 4WD front wheels lock in "Park", while in 4WD?

Thanks for the answers and good advice!<br /><br />P51D

 

[rodbolt]

Re: Do 4WD front wheels lock in "Park", while in 4WD?

im with nitedmn<br /> the parking pawl is located in the transmission, they fail occasionally.<br /> set the brake, if the ramp is exceptionally steep set the brake and chock the front wheels.<br /> I have seen to many rigs slide down the ramp after power loading due to the rear tires sliding down the ramp on ramp slime.<br /> depending on how big,mad,drunk the driver is mandates how much I can laugh while pulling them out.

 

[brownies]

Re: Do 4WD front wheels lock in "Park", while in 4WD?

The answer to the question is yes. <br />With the vehicle in "park" and the e-brake set AND if the rear wheels loose traction (slime/ice/etc). The vehicle may slide down the ramp. The rear wheels would be sliding, the front wheels would be rolling.<br />UNLESS, the front differential (axles AND transfer case) were engaged. <br />If the front was engaged in 4wd, then the front wheels would not roll while in park. They would HAVE to slide along with the rears for the vehicle to move.<br /><br />The park "paul" and the e-brake would have no effect on the loss of traction that you inquired about enabling any of the wheels to slide.

 

[P51D]

Re: Do 4WD front wheels lock in "Park", while in 4WD?

Brownies - Your explanation makes it clearer for me. Thanks for reinforcing it.<br /><br />P51D

 

[rodbolt]

Re: Do 4WD front wheels lock in "Park", while in 4WD?

if the parking pawl breaks the transmission is unlocked and all the asseblies can roll unless another mechanical means of locking the axles has been provided.<br /> we used to pull 4 or 5 out of the creek every summer when power loading was done at low tide.<br /> that constant push then the sudden throttle chop tends to start it sliding down the ramp.<br /> its funny to watch, unless its happening to you.<br /> I almost launced my boss's diesel F250 one day at the norfolk yacht and country club.

 

[SpinnerBait_Nut]

Re: Do 4WD front wheels lock in "Park", while in 4WD?

Ford had a bad history of pawl failures in the past, guess they have fixed them now.

 

[Silvertip]

Re: Do 4WD front wheels lock in "Park", while in 4WD?

I've seen the parking pawl mount torn out of the tranmission case.

 

[heycods]

Re: Do 4WD front wheels lock in "Park", while in 4WD?

Originally posted by SBN:<br /> Ford had a bad history of pawl failures in the past, guess they have fixed them now.

I can personaly attest to that.