bansil
Senior Member
My views and thoughts on driving in the mountains with a FE bus with the 5.9 Allison 545 combo.
I just returned from a 400 mile trip from Mnt City TN south thru Boone via 421 past Winston-Salem, I learned a lot and would like to pass it on for others,since I couldn't find the answers I needed.
Disclaimer:these are my two penny"s and use them as you like.
I was having over heating issues (due to tranny temps climbing as well as coolant temps climbing) not dangerously high but high enough I had to stop and sometimes not continue up mountain's since I have had the bus for the last 6months.
the answers to POINT ONE (1 penny).............................
GOING UPHILL
I asked a few older school bus drivers"how do you drive up this mt, w/o over heating or killing the trans?"
they said (I shorten the stories but this is basic info)"2200 rpm is the magic number,find your speed in each gear at 2200 on flat ground and make that the minimum plus 5 mph for each gear"
I approached the mountain and slowed to about 25mph, shifted down to 2nd and rolled into throttle building boost and held it at 2200/2300 rpm when I hit the rpm i was doing 30 mph and several miles later I was in Boone,N.C. coolant/trans never went above 185 engine and 200 trans (convertor out)
Perfect!!
We continued on following same guidelines I established:
1st gear=15-20mph 2200 rpm
2nd gear=30-35mph 2200 rpm
3rd gear=45-50mph 2200 rpm
4th gear was useless to me since the rolling hills never let me use it with out being below my target rpm, and tranny would slip as boost built and temps would rise,so I drove a gear down,and 50mph.
POINT NUMBER TWO (2nd penny)
GOING DOWNHILL
Heading out of Boone down 421 was the mountain; an evil 6 miles down into N.Wilkesborro
I put tranny into 1st at top of hill and crested at about 10 mph (no lockup convertor)rpm's made tranny shift into 2nd,since I was playing the game of precaution I was nervous and used 30mph as my "set speed" I had to apply the brakes several times and even pulled over and checked brake temps at
a spot between the runaway ramps...cool to touch OK I'm good so we continued on.so I basically coasted hoping the tranny and engine would hold us back
Here is the point :wink:
on way back,I climbed the mt with no worries and no temp variation...cool...but I had 2 down hills that worried me.
I crested and rolled by the Eastern Continental Divide sign and knew there was a red light at the bottom of the grade...
I shifted into 1st gear and drove at about 1500 rpm to make the transition from flat to down hill, as I was "driving" down the mountain contemplating how I would approach this light I realized that I was all ready 1/3 way down and still doing 15 mph!!!! :shock:
As long as I "drove" not coasted, the tranny held back just fine....so I drove down that incline in 1st gear at 1500/1700 rpm...I feathered throttle to maintain pressure but not rev motor.
I was happy.
The road out of Boone back towards Mt City is a lot steeper with a damn gas station at the bottom.
I "drove" down at 20 mph and 2000rpm,when engine started to creep up I used my left foot to apply the brakes for a split second(2 times total) so I still had throttle pressure applied
Sorry this is so long winded, I hope this helps someone out and gives them an idea or 2...
SIDE NOTE: I AVERAGED 8-1/2->9-1/2 MPG AT THOSE RPM'S
I just returned from a 400 mile trip from Mnt City TN south thru Boone via 421 past Winston-Salem, I learned a lot and would like to pass it on for others,since I couldn't find the answers I needed.
Disclaimer:these are my two penny"s and use them as you like.
I was having over heating issues (due to tranny temps climbing as well as coolant temps climbing) not dangerously high but high enough I had to stop and sometimes not continue up mountain's since I have had the bus for the last 6months.
the answers to POINT ONE (1 penny).............................
GOING UPHILL
I asked a few older school bus drivers"how do you drive up this mt, w/o over heating or killing the trans?"
they said (I shorten the stories but this is basic info)"2200 rpm is the magic number,find your speed in each gear at 2200 on flat ground and make that the minimum plus 5 mph for each gear"
I approached the mountain and slowed to about 25mph, shifted down to 2nd and rolled into throttle building boost and held it at 2200/2300 rpm when I hit the rpm i was doing 30 mph and several miles later I was in Boone,N.C. coolant/trans never went above 185 engine and 200 trans (convertor out)
Perfect!!
We continued on following same guidelines I established:
1st gear=15-20mph 2200 rpm
2nd gear=30-35mph 2200 rpm
3rd gear=45-50mph 2200 rpm
4th gear was useless to me since the rolling hills never let me use it with out being below my target rpm, and tranny would slip as boost built and temps would rise,so I drove a gear down,and 50mph.
POINT NUMBER TWO (2nd penny)
GOING DOWNHILL
Heading out of Boone down 421 was the mountain; an evil 6 miles down into N.Wilkesborro
I put tranny into 1st at top of hill and crested at about 10 mph (no lockup convertor)rpm's made tranny shift into 2nd,since I was playing the game of precaution I was nervous and used 30mph as my "set speed" I had to apply the brakes several times and even pulled over and checked brake temps at
a spot between the runaway ramps...cool to touch OK I'm good so we continued on.so I basically coasted hoping the tranny and engine would hold us back
Here is the point :wink:
on way back,I climbed the mt with no worries and no temp variation...cool...but I had 2 down hills that worried me.
I crested and rolled by the Eastern Continental Divide sign and knew there was a red light at the bottom of the grade...
I shifted into 1st gear and drove at about 1500 rpm to make the transition from flat to down hill, as I was "driving" down the mountain contemplating how I would approach this light I realized that I was all ready 1/3 way down and still doing 15 mph!!!! :shock:
As long as I "drove" not coasted, the tranny held back just fine....so I drove down that incline in 1st gear at 1500/1700 rpm...I feathered throttle to maintain pressure but not rev motor.
I was happy.
The road out of Boone back towards Mt City is a lot steeper with a damn gas station at the bottom.
I "drove" down at 20 mph and 2000rpm,when engine started to creep up I used my left foot to apply the brakes for a split second(2 times total) so I still had throttle pressure applied
Sorry this is so long winded, I hope this helps someone out and gives them an idea or 2...
SIDE NOTE: I AVERAGED 8-1/2->9-1/2 MPG AT THOSE RPM'S
Ya just save my butt again thanks ya'll...
