TEMPS: Downhill in a PT-42 Series 60/Allison

[Pete Masterson]

I guess my coach is in MODE OFF -- I've always noticed that it shifts more than I'd shift if I were doing it myself. I do set it to hold a gear when it gets into a gear-hunting situation on an up grade. And I've used the up-down arrows on many occasions as conditions dictated.

I'll have to experiment with the MODE ON ... now that I reflect on it, I remember the MODE button -- it was one of those things I intended to review in the manual once I got around to it -- and I guess I never got around to it...

It sounds like MODE ON will make some of those relatively flat freeway stretches with the occasional overpass, etc. less shifty...

FWIW, I've never had the jake come on while going up hill. The Jake is fully integrated into the system (when it is enabled) so it comes on whenever the coach is decelerating. I guess you must be taking your foot off the throttle -- that would trigger the Jake...

I do get the jake kicking in (often unnecessarily) while in cruise while going down a very slight decline. Depending on the terrain, that's when I'll often disable the jake...

Pete Masterson

'95 Blue Bird Wanderlodge WBDA 42

El Sobrante CA

"aeonix1@mac.com"

On Jun 17, 2008, at 4:38 PM, bumpersbird wrote:

Pete,

On your Allison control pad or I should say I have, D,N,R on one side 

on the other side I have one arrow up, one arrow down, and MODE.

Mode is either off or on. It is a preset program designated by the 

builder as to how the transmission operates. The mode off is a 

factory default setting.

In my case when in MODE ON the coach just runs mostly in 6th at 

highway speeds and only down shifts once the engine has allready drop 

under something like 1300 RPM. So she's already bogged down. It's  

great on the flats. 

With MODE OFF she tends to shift a bit too much in cruise. Hit that 

overpass and she drops to 5th right now. Keeps the speed set on the 

silver leaf exactly, and if it's a long haul uphill the RPM's stay up 

and she'll drop to 4th. and just rip up a hill.

I would say in MODE OFF the is tranny working harder, and in MODE ON 

the engine is trying to throw power at the tranny. I would like 

something in the middle. I guess thats why I started hitting shift 

buttons. If I'm cruising down the freeway and in MODE ON and in 

cruise, if she doesn't shift befor loosing too many RPM I'll do it 

for her.

The arrow keys let you shift gears up or down. Of course you have to 

be in the correct RPM range befor she will change gears.

It seems as though my jake is sensitive even a small overpass will 

set it off if it's in cruise. The motor spins up just in time for the 

jake to cut in.

By the way it will do this going uphill to. Does anyone know why that 

happens?