Mountain driving

[Mile Marker 42]

Originally Posted by wolfe10

If by "set for 2nd gear" you mean that is what the Allison shift pad shows (aka pre-select gear, that does NOT mean the transmission is in second gear, but will continue to downshift toward 2nd gear as long as the next lower gear will not overspeed the transmission. VERY DIFFERENT. Kind of like the shift pad showing "6" while at a stop light. That is the gear toward which it will go, not the gear it is in.


2nd gear for most coaches (depends on gearing) will be in the mid 20 MPH range.

I know that "set for 2nd" doesn't mean it is in 2nd. I have lots of mountain driving experience. I actually found out my Pac Brake was stuck open 8 years ago on a 10% grade. Had just put brand new brakes, calipers, rotors all the way around and just converted front wheels bearings to wet bath. Was lucky to get her under control and off to the side with all 4 smoking. Cop pulled up behind me and I told him my brakes were smoking and I couldn't stop. He said "I know, I could smell them". Unhooked the tow car, cooled the brakes down, finished our trip and got home and called Pac Brake. Was thinking about unsticking the original Pac Brake but they told me they had upgraded it a lot since 2003:-) I ordered that and put it on.

[HenryH001]

Originally Posted by wolfe10

If by "set for 2nd gear" you mean that is what the Allison shift pad shows (aka pre-select gear, that does NOT mean the transmission is in second gear, but will continue to downshift toward 2nd gear as long as the next lower gear will not overspeed the transmission. VERY DIFFERENT. Kind of like the shift pad showing "6" while at a stop light. That is the gear toward which it will go, not the gear it is in.


2nd gear for most coaches (depends on gearing) will be in the mid 20 MPH range.

Thanks. I was thinking my Allison was not reading the gear correctly. I wish it showed the current gear it was in.

[wolfe10]

Originally Posted by HenryH001

Thanks. I was thinking my Allison was not reading the gear correctly. I wish it showed the current gear it was in.

Some of the Allison shift pads had only the ONE window (pre-select gear), others do have two windows, with the left being the pre-select gear and the other being the actual gear the transmission is in.


Another option is to develop an RPM/gear/MPH chart and learn it.


Here is the formula for our specific 2003 Alpine 38' with Cummins ISL, Allison 3000 series and 4.63 rear axle ratio, and 275/80R22.5 tires:


(RPM x 60) / (4.63 x 516 x transmission ratio) = MPH
where 4.63 = rear axle ratio and 516 = tire revolutions per mile


- or -

(RPM x .0251142) / transmission gear ratio = MPH



Yet another is to get one of the monitoring systems and use transmission gear as one of the displayed items.

[bentjm]

Originally Posted by HenryH001

Thanks. I was thinking my Allison was not reading the gear correctly. I wish it showed the current gear it was in.

I agree that showing the actual gear would be great.

[Crasher]

Originally Posted by bentjm

I agree that showing the actual gear would be great.

My Allison shows the intended gear along with the actual gear it is in. Our 2003 Phaeton, 2011 Phaeton and our current 2013 Bus all had/have dual numbers displaying the target gear along with current gear.

[FL420]

Four years ago DW and I attended the week long 2017 Maintenance Session put on every spring by the Ramblin' Pushers club for owners of Monaco and Holiday Rambler coaches. DW and I had so many seminars to go to we kept passing each other every hour on our way to the next seminar we were interested in attending.
At the seminar presented by an Allison employee I asked him if I could trade my single window shift control in my 2005 Monaco Knight for the one with a 2 digit display. He said that wasn't possible. Bummer!
I had driven school buses in the mountains with the single digit and buses with the 2 digit display and much preferred the 2 digit display. With only a single digit my workload was greatly increased by having to hawk the tachometer to figure out when or if the tranny actually downshifted when I selected a lower gear.
I highly recommend owners of Monaco and Holiday Rambler coaches who want to learn all about their coaches look into attending a Maintenance Session. This year it is from April 27 through May 5. More info can be obtained from:
Carol Smalley
Database Manager
Ramblin’ Pushers
618-537-9999
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[tropical36]

Originally Posted by kengardner

I'm still shopping for a DP and need some honest opinions on Exhaust brake vs Engine brake for a lot of mountain driving pulling a new Jeep Wrangler. I have searched and am not finding anything. I'm trying to decide between an older 40-45 foot, 400 + hp which will have an engine brake and a newer and shorter 36-38 foot which will have an exhaust brake since almost all have a 340-360 hp engine. I have driven a 34 foot gasser pulling a jeep and it was touch and go in the steep mountain areas even starting out very slow and trying to stay in lower gears. The 10 cyl Ford engine would really get to high rpms and I would jab the brakes hard to drop the rpms and in only a short distance was right up there again. The wife would not drive in those areas and did not really even want to be a passenger. Can I expect the smaller DP with an exhaust brake to slow the DP down better than the gasser with tow / haul and gearing ??? A few of the trouble spots were I-70 west of Denver, I-75 west of Chattanooga, and I-81 or 77 ?? near the Shenandoah Valley. At all of those places and a few others the cool down areas were busy and I also needed to stop for a while to cool down and remove my wife's finger nails from my arm ! We would both rather have a shorter DP to enable us to fit into more state / national parks but do not want to white knuckle to get there. Please give me some opinions. I found several posts a while back but can't locate them now. Ken

I'm happy with a PAC exhaust brake, although I'd rather have an engine brake. Thing is and for a chassis that has it, you're talking more money.
In answer to your question, our old gasser had nowhere near the stopping power as our present DP and for many times not using the brakes at all.
Boiling brake fluid is not your friend either, so in the meantime, be careful of stopping to cool things down, as this isn't always a good idea.
And they do make smaller DP's if size is of any concern. NOT!