Why no Park on a Class A Motorhome transmission

[ronnie_g]

I am new to Motor-homes and of recent have had visits with grandkids in the RV.
Time to time I have worried "What IF" some one bumps into or being a 'kid' pushes in the parking brake. If my leveling jacks are not down, the RV could roll off?
Any thoughts as to why their is not a P PARK lock in the transmission.
I am thinking the other alternative would be to drain off the storage tank for the brake system?
Same concern making a quick stop at a rest area, buying food / fuel etc. Wouldn't a PARK be a safety feature?


Do you take any precautions for this?

[bruceisla]

Originally Posted by ronnie_g

I am new to Motor-homes and of recent have had visits with grandkids in the RV.
Time to time I have worried "What IF" some one bumps into or being a 'kid' pushes in the parking brake. If my leveling jacks are not down, the RV could roll off?
Any thoughts as to why their is not a P PARK lock in the transmission.
I am thinking the other alternative would be to drain off the storage tank for the brake system?
Same concern making a quick stop at a rest area, buying food / fuel etc. Wouldn't a PARK be a safety feature?


Do you take any precautions for this?

What motorhome (manufacturer/yr/model) are you referring to?


My old Endeavor and current Newmar with Allison transmissions had a Park (P) on the keypad.

[rk911]

all of our motorhomes have had a ‘park’ selection. what makes you think yours does not?

[ronnie_g]

Originally Posted by rk911

all of our motorhomes have had a ‘park’ selection. what makes you think yours does not?

2013- Now, 2006 Itasca Meridian 36G,


No PARK

[bruceisla]

Originally Posted by ronnie_g

2013- Now, 2006 Itasca Meridian 36G,


No PARK

Ahah! .... yes, the Allison 2500 uses a hydraulic drum brake instead of a Parking Pawl. Obtain the Allison 2500 instructions for details on parking.

[ronnie_g]

Allison 2500 uses a hydraulic drum brake instead of a Parking Pawl. Obtain the Allison 2500 instructions for details on parking.



Thanks, I'll look for info
Well I have a 3000, but still looking.....

[ronnie_g]

Allison 3000 instructions don't really say the transmission has a Park...
Link is for 3000 & 4000 instructions

Still reading...

http://ddwt.us/Allisson_4000MH_Trans...ers_Manual.pdf



26
PARKING BRAKE
Select
N
(Neutral) and be sure that the parking brake is applied to secure the vehicle
when it is not attended. Always make sure the vehicle’s parking brake system has
been maintained per the manufacturer’s specifications.
TOWING OR PUSHING
The engine cannot be started by pushing or towing. Before pushing or towing a
vehicle, disconnect the driveline, lift the drive wheels off the road, or remove the
axle shafts from the drive wheels. When the axle shafts are removed, be sure to
cover the wheel openings to prevent loss of lubricant and entry of dust and dirt. An
auxiliary air supply will usually be required to actuate the vehicle brake system.
TURNING OFF THE VEHICLE
Always select
N
(Neutral) prior to turning off the vehicle engine.

[ronnie_g]

IMO their is no 'park' associated with the transmission?


WARNING:
Vehicle service brakes, parking brake, or emergency
brake must be applied whenever
N
(Neutral) is selected to prevent
unexpected vehicle movement. Selecting
N
(Neutral) does not
apply vehicle brakes, unless an auxiliary system to apply the
parking brake is installed (see Operator’s Manual for the vehicle).

[Duoglide1]

Cut a short piece of pvc pipe. Then cut a slot out of the side so you can slide it in sideways under the parking brake button. I’ve seen people do this with large dogs.

[bruceisla]

Originally Posted by ronnie_g

Allison 3000 instructions don't really say the transmission has a Park...
Link is for 3000 & 4000 instructions

Still reading...

http://ddwt.us/Allisson_4000MH_Trans...ers_Manual.pdf



26
PARKING BRAKE
Select
N
(Neutral) and be sure that the parking brake is applied to secure the vehicle
when it is not attended. Always make sure the vehicle’s parking brake system has
been maintained per the manufacturer’s specifications.
TOWING OR PUSHING
The engine cannot be started by pushing or towing. Before pushing or towing a
vehicle, disconnect the driveline, lift the drive wheels off the road, or remove the
axle shafts from the drive wheels. When the axle shafts are removed, be sure to
cover the wheel openings to prevent loss of lubricant and entry of dust and dirt. An
auxiliary air supply will usually be required to actuate the vehicle brake system.
TURNING OFF THE VEHICLE
Always select
N
(Neutral) prior to turning off the vehicle engine.

Yup .... I stand corrected .... it's actually labeled N (neutral) and doesn't use a parking pawl. Step on foot brake, shift to neutral, select parking brake, turn ignition off.


The Allison assumption is that a conventional parking pawl (like a car) will break if the very heavy vehicle is moved or loaded against the pawl on a grade.

[ronnie_g]

Originally Posted by Duoglide1

Cut a short piece of pvc pipe. Then cut a slot out of the side so you can slide it in sideways under the parking brake button. I’ve seen people do this with large dogs.

Yep, you are the winner!!!!

Keep It Simple

I would have thought of this, maybe in 3 or 4 years....

[Skip426]

Lack of a park pawl in the trans of the larger Class A units with the 3000 + series of Allison transmissions , is probably due to the size of the hub inside the trans and the pin that would be required to guarantee it wouldn't snap off , if the RV decided to start rolling, when the pin was't fully engaged.
Ever placed your car in park; on an incline; then had it roll 5/6" when you release the brake pedal, and stop with a jerk as the pin hits home.
The park pin in most automatic transmissions is about the size of your little finger tip, and I've replaced those, and the engagement hub in a 4,000 lb car because they snapped off.
Imagine the damage a 30 k + motor home would do , and the size of pin/hub it would take to make sure things didn't snap every time , the coach rolled a little to the proper engagement point.
To avoid damaging your car transmission ; set the parking brake , before you shift into park , and release the foot brake.
In your coach you set the park brake , then if you want a secondary , mechanism ; solid rubber wheel chocks.

EDIT: I see Bruce posted the simplified version , while I was away typing , sorry for the duplication.

[ronnie_g]

Then is it safe to assume few Class A's have a parking brake?

I'll be playing with the PVC first chance I get......

Heck in my area, People with standard transmissions have stopped thieves. Apparently the common thief in my area can't drive a standard.

PVC ring might also stump them??
I like the concept of a simple piece of plastic being the solution.

Thanks to all for their input.

[ThePowells]

Another train of thought.

http://www.irv2.com/forums/f258/diy-...es-399727.html