What happens to 4X4 once you put in park

denis Laouenan · Apr 21, 2022

Sorry for my lack of knowledge, something I find important when towing a boat to the ramp is what happens to the 4X4 when you put in park and leave the truck to go get your boat on the trailer. I fear that in park only the rear wheels are locked regardless of the 4X4 selection and leaves you with braking and locking only to the rear wheels, those that happen to be the most on fouling weeds etc. If the rear wheels loose grip and you are not in the truck to push the brake pedals you're done. I boat mostly alone and I don't have someone staying in the truck while I steer the boat on the trailer. Thanks for your input.

audiophile · Apr 21, 2022

If you are in 4wd, the front wheels can only turn if the vehicle is in drive. Though I have never had an issue with the boat ramp personally, I don't see anything happening. If you are really concerned, get yourself a set of wheel chocks ti keep in the bed.

denis Laouenan · Apr 21, 2022

Too late for me to have concerns, truck was in 4wd lock, park and em brake but still went in... Can't figure if rear wheels slept or park jumped out. If you are sure front wheel are lock also in park then park jumped out.

IDSandman · Apr 21, 2022

You had the truck in 4 wheel, in park AND parking brake firmly set and the truck still went into the lake? Your ramp a 50deg slope and covered in ice? Yeesh! All in the span of 27 mins, new record! Lol.

denis Laouenan · Apr 21, 2022

You can LOL as much as you want, I have been trailering to the ramp thousands of time in 40 + years, I also though "not me"

denis Laouenan · Apr 21, 2022

Yes 4wd, brake and park, talked to an officer for 3 or 4 min outside the truck nothing was happening then started to walk away on wharf to get in the boat when the officer started to shout, turned back the truck was going fast in...

MADDOG · Apr 21, 2022

When the truck is in park, the transmission is locked which stops output to the transfer case, driveshafts and differentials.

So having it move could have been caused by a mechanical failure (parking pawl broke) or a slick ramp. Depending on the percent grade on the ramp the e-brake may or may not hold the truck.

denis Laouenan · Apr 21, 2022

It's hard to be sure cause watching your truck go and jumping in is quite a chock to the system but I'm quite sure the front wheels were turning, in fact they had to otherwise no way the truck would have gone. The front wheels were on dry and clean cement. Almost new michelin defender. Something gave and the all transmission was free. That's my theory. the emergency brake is not powerfull enough to stop the truck on a ramp with a 1000 lbs trailer in the back. I'm also thinking that possibly when the truck was towed away from a publix parking 2 months ago some damage was done to the park lock keys or pawl.

denis Laouenan · Apr 21, 2022

If you guys who know are sure the front wheels remain coupled with the transmission when in park then the park jumped out. That was my doubts cause if they were not locked then I could explain I was too close the the weed line at low tide and lost the rear and the front just followed. If they were locked some mechanical failure happened.

MADDOG · Apr 21, 2022

Sound like a failure of the transmission linkage & parking pawl then.

As long as you are in Park then the driveshaft(s) should not turn including the front when in 4WD.

Heatheroo · Apr 21, 2022

Are we gonna hear the rest of the story? Did your truck end up submerged?

Mister Luck · Apr 21, 2022

I park on a 4 to 6 % grade and I found if I use 4 Lo it helps to keep my (auto transmission) truck from rolling it keeps all 4 tires engaged I think it puts less strain on the parking brake
When I go up the driveway in 4 Lo it takes less throttle for traction only 4 Lo not 4 Hi

On a boat ramp I would think it could help but it only takes 4 to 6 inches of water to displace a vehicle under 1 ton , I’d think (a boat) if it was over 20ft could easily move a vehicle while sitting in the water not free of the trailer.

IDSandman · Apr 21, 2022

Hopefully it didn’t go to deep. Sounds like the park pawl was damaged before and broke. Maybe also have your park brake checked. Mine holds like crazy, even wet. I also have a small paver brick in my bed I chock with when launching/retrieving by myself. Curious why you’re in 4wheel? Ramps that slick there? Hopefully you disengage before make a turn on dry pavement with all that weight.

denis Laouenan · Apr 21, 2022

Mainly posting to help others understand their truck functions.

392DevilDog · Apr 21, 2022

denis Laouenan said:
It's hard to be sure cause watching your truck go and jumping in is quite a chock to the system but I'm quite sure the front wheels were turning, in fact they had to otherwise no way the truck would have gone. The front wheels were on dry and clean cement. Almost new michelin defender. Something gave and the all transmission was free. That's my theory. the emergency brake is not powerfull enough to stop the truck on a ramp with a 1000 lbs trailer in the back. I'm also thinking that possibly when the truck was towed away from a publix parking 2 months ago some damage was done to the park lock keys or pawl.

The parking brake is designed and tested to hold 17000lbs GCWR. So...even with a broken park pawl...it had to be a loss of traction between the tires and the boat ramp.

If you have the transfer case with 4wd auto...when the truck is shut off the clutches no longer hold, so, if the truck was off...the front wheels would spin as the truck slid into the water.

Hmm.

crash68 · Apr 21, 2022

392DevilDog said:
If you have the transfer case with 4wd auto...when the truck is shut off the clutches no longer hold, so, if the truck was off...the front wheels would spin as the truck slid into the water.

I don't think the BW44-44 transfer case keeps the front wheels engaged when the truck is in park either. Probably need one of the override switches that one of the members was making.

IDSandman · Apr 21, 2022

denis Laouenan said:
Mainly posting to help others understand their truck functions.

We all are…… hence the questions we are asking and help given…

denis Laouenan · Apr 21, 2022

Truck was in 4wd lock, engine running, knob on park. It is one fitted with the 4wd auto.

crash68 · Apr 21, 2022

denis Laouenan said:
It is one fitted with the 4wd auto.

That is the Borg Warner 44-44 transfer case. Even though the setting states 4X4 Lock it doesn't engage the front wheels unless slippage is detected.

denis Laouenan · Apr 21, 2022

How about in 4wd low?

What happens to 4X4 once you put in park

Junior Member

Senior Member

Junior Member

Senior Member

Junior Member

Junior Member

Out Exploring Arizona

Junior Member

Junior Member

Out Exploring Arizona

Member

cassis tutissima virtus

Senior Member

Junior Member

Senior Member

ACME product engineer

Senior Member

Junior Member

ACME product engineer

Junior Member

Similar threads

Forum statistics

Share this page