Among the many things that we have learned in our first year on the road is that the Allison transmission in our 2000 Foretravel should be manually shifted when climbing hills.
Falure to do so when climbing long grades can lead to a situation called "lugging." When your engine is lugging it is running at too low of RPMs for the grade. This is not good for the transmission and is especially bad for the diesel engine. By shifting down to a lower geat you tell the engine to run at a higher rate of RPMs and this adds more cooling ability to the engine because the fan is turning over quicker and moving more air.
A rule of thumb when climbing hills is 3rd gear for the 30s and 4th gear in the 40s (MPH).
Another thing we learned about our Allison transmission is to use the Economy mode when not in hilly country. It will improve fuel mileage.
I hope what we have leanred might help others.
Luvglass said
05:31 AM Sep 13, 2010
Doesn't your transmission down shift automatically when you go up hills? Ours does in the Ford. Do you have a manual transmission?
bjoyce said
07:32 AM Sep 13, 2010
I am glad Allison has made changes since 2000 since our 2004 one automatically downshifts. Economy mode moves the shift points so the engine stays in higher gears more, which is why you don't use it on hills. It does not help on fast roads either since you will be driving in 6th gear anyway, it helps best between 30 and 50 mph.
Jim01 said
09:00 AM Sep 13, 2010
Our 1992 with an Allison 4 speed automatically shifts down. I would think they all would, but then you never know.
Jim
Bill and Linda said
11:41 AM Sep 13, 2010
Interesting comment, I just learned something about the Allison in motorhomes.
I guess the ones in the MH don’t have the “Tow-Haul” feature like the Allison 1000 series in the Chevy / GM pickups.With the transmission in Tow-Haul the problem you indicate isn’t present.
Mine has always shifted, when in Tow-Haul, at just the right point and has never “lugged” going up hill.I just have to use manual shift mode when coming down a long grade and I want the tranny to down-shift and slow me down sooner than it normally would.I can see the hill ahead of time – it can’t unless I touch the brakes.With the Allison, I don’t need to touch the brakes very often.
Safe travels
Bill
foxriverguy said
09:13 PM Sep 13, 2010
Fred,
It does not downshift under all conditions. We have become "pro-active" (hate that term) in that when we see a steep hill coming up, we downshift accordingly.
GENECOP said
10:34 AM Sep 14, 2010
It has always been my understanding that Automatic transmissions shift when and as needed, the whole concept behind an automatic is the ability for the vehicle to put itself automatically in the most optimum gear that it needs according to road conditions. Can you please show us the source Of your info, definitely interested in learning something new, G
This gives some pointers on the Allison transmission shifting. You don't want to allow your engine to lug going uphills and if you downshift when going downhills and keep the RPM's above 2000, MH's with exhaust brakes will work better.
Hope this helps, if not let me do some more digging.
Falure to do so when climbing long grades can lead to a situation called "lugging." When your engine is lugging it is running at too low of RPMs for the grade. This is not good for the transmission and is especially bad for the diesel engine. By shifting down to a lower geat you tell the engine to run at a higher rate of RPMs and this adds more cooling ability to the engine because the fan is turning over quicker and moving more air.
A rule of thumb when climbing hills is 3rd gear for the 30s and 4th gear in the 40s (MPH).
Another thing we learned about our Allison transmission is to use the Economy mode when not in hilly country. It will improve fuel mileage.
I hope what we have leanred might help others.
Jim
Interesting comment, I just learned something about the Allison in motorhomes.
I guess the ones in the MH don’t have the “Tow-Haul” feature like the Allison 1000 series in the Chevy / GM pickups. With the transmission in Tow-Haul the problem you indicate isn’t present.
Mine has always shifted, when in Tow-Haul, at just the right point and has never “lugged” going up hill. I just have to use manual shift mode when coming down a long grade and I want the tranny to down-shift and slow me down sooner than it normally would. I can see the hill ahead of time – it can’t unless I touch the brakes. With the Allison, I don’t need to touch the brakes very often.
Safe travels
Bill
It does not downshift under all conditions. We have become "pro-active" (hate that term) in that when we see a steep hill coming up, we downshift accordingly.
http://www.mydrv.net/Maintenance_Seminar/allison_transmission_operation.htm
This gives some pointers on the Allison transmission shifting. You don't want to allow your engine to lug going uphills and if you downshift when going downhills and keep the RPM's above 2000, MH's with exhaust brakes will work better.
Hope this helps, if not let me do some more digging.
Best Regards!