Community Forums

ed32425 · 08-12-2018, 08:57 AM

I'll be making my first real mountain trip shortly, I have a Fleetwood Discovery with 350hp cumming
motor and a 6 speed Allison 3000MH. Any tips on driving or transmission shifting up and down the mountain, Thanks Ed

Smitty77 · 08-12-2018, 09:11 AM

You can see in advance the grade ahead, and be pro-active in dropping gears to keep the RPM's in the sweet spot for power. (If you don't have the rating for your specific engine, call Cummins and give them you engine SN. They can provide peak HP and Torque. Keep your RPM's up at or slightly above peak HP for hill climbing.) Waiting for the ECM's between the Engine and Allison to downshift, is reactionary to the hill grade. Sometimes it's too late, and the rest of the hill climb is a bit slower. Higher RPM's should also help in cooling.

Down hill, drop the gears early. Limit using the brakes. Say if you want to maintain a 40MPH speed, drop into 3rd or 4th gear, depending upon our coaches gearing. When speeds creep up to say 45MPH, stab the brake and brake semi hard to get the speed back down. If I want to hold 40MPH, I'll drop it down to 35MPH if I need to use my brakes. (We have the ISL, with the 2 Stage Jake Compression, so most of grades I use the brakes very seldom. Your ISC should have an Exhaust Brake, which is for sure good to have. But you may find, especially if you have a larger toad, that you will need to use the service brakes on the decent.)

Other then that, have a good time. Oh, invest in the Eastern or Western or both Mountain Directory Book, and pre plan your routes to avoid hills that you or the DW may not want to tackle

!

Have fun, best,
Smitty

Jake21 · 08-12-2018, 09:12 AM

I down shift manually and keep my RPMs to around 1700 when climbing. For the downhill, it is either in 3rd or 4th depending on the grade and I use the engine brake as needed to maintain speed. Use the brakes as needed but do not lay on them.

TonyMac · 08-12-2018, 09:25 AM

First and foremost, it's a bus, not an suv. It's heavy, lacks power to weight, and the brakes can overheat if used excessively. It just drives different, mostly in the right lanes with the semis.

Know your sweet spot; the lowest rpm that produces the most power, typically about 1800ish, and know your redline, the highest rpm permissable. Read the book or ask people on this site who have your same setup. (I'm a CAT 350, soooo..)

While going up, it the tranny starts to hunt, shifting down gaining speed and then shifting up and losing speed, manually select the lower gear, rpm in the sweet spot, and take whatever mph that gives you. As the road flattens, manually up shift one or two. Watch your temps

Plan to go downhill in the same gear you went uphill in. Use your engine brake as your primary brake, with firm stabs at your foot brake to get well below redline rpm. You may need to downshift further. A firm stab at the foot brake, slow till the tranny downshifts, then get off the brake to let them cool.

I like flashers on when speed is less than 45 mph, going up or down. It kinda tells the guy coming up that you are slow. Otheres herein disagree.

TonyMac · 08-12-2018, 09:31 AM

"Other then that, have a good time. Oh, invest in the Eastern or Western or both Mountain Directory Book, and pre plan your routes to avoid hills that you or the DW may not want to tackle

!"

Smitty is so right. Twice I found myself someplace I did not want to be, because I failed to plan. Stupid. Now I have the books Smitty advises. No surprises is better.

Jake21 · 08-12-2018, 09:31 AM

I have heard more than a few times, “Go downhill hill in the same gear you went uphill in”. I don’t understand this general statement. If I climb for 3 miles at a 6% grade, then crest the hill and descend for 1/2 mile at a 2% grade, I will not be in the same gear.

OLYLEN · 08-12-2018, 09:37 AM

I always use the best cooling RPM on a climb, should be published in the motor manual. Down hill as above start SLOW geared down, depending on your weight and if towed will impact the choice of gear for the descent as well as the grade.

LEN

Bigd9 · 08-12-2018, 11:09 AM

Quote:

Originally Posted by Jake21

I have heard more than a few times, “Go downhill hill in the same gear you went uphill in”. I don’t understand this general statement. If I climb for 3 miles at a 6% grade, then crest the hill and descend for 1/2 mile at a 2% grade, I will not be in the same gear.

Like you, I never could see the logic in that statement. It is rare the uphill is the same as the down hill.

MSHappyCampers · 08-12-2018, 11:10 AM

Hi !

Welcome to IRV2! We're sure glad you joined the gang!

I can't add anything to what others have said. Just take it slow!

Good luck, happy trails, and God bless!

TonyMac · 08-12-2018, 11:15 AM

Quote:

Originally Posted by Jake21

I have heard more than a few times, “Go downhill hill in the same gear you went uphill in”. I don’t understand this general statement. If I climb for 3 miles at a 6% grade, then crest the hill and descend for 1/2 mile at a 2% grade, I will not be in the same gear.

Plan, you gotta have a plan.

owow

jimmy braden · 08-12-2018, 11:22 AM

Got a toad? My CUMMINS and ISC350 manage hills fine with no toad.
weight is 30K. I imagine you are close.

Climbs like the dinkens. Rarely drops down to 5th at 60 mph cruise and 1580rpm

tropical36 · 08-12-2018, 12:09 PM

Quote:

Originally Posted by ed32425

I'll be making my first real mountain trip shortly, I have a Fleetwood Discovery with 350hp cumming
motor and a 6 speed Allison 3000MH. Any tips on driving or transmission shifting up and down the mountain, Thanks Ed

Since I run with the exhaust brake on at all times, the Allison will usually take care of itself, once I touch the brakes, going down hill.
Same with going uphill and will usually just let it's brain do the gear figuring.
However, with going downhill, it's always best to try and maintain a speed, whereas the brakes aren't needed or at least for very little, so if the tranny won't hold it back, then jam them on and hold for a bit, now and then for slowing down.
Riding the brakes or pumping the pedal, is a no no with either hydraulics or air!

Ivylog · 08-12-2018, 01:51 PM

I agree a Allison is pretty smart when it comes to hills but for climbing mountains you often need more cooling than what it ma.y give you. You may be able to climb with the Mode red light off and let it do it's thing BUT on some curves you have to slow down so the Allison is going to upshift on you...time to manually select a gear that keeps your RPMs above 1750.

It's better to start down in the same gear (Yes, they are not all the same both ways) but it's easier to increase your speed than to try and reduce it. I like to keep the braking to 5 seconds out of every 30 which gives me a faster down than going up.

lwmcguire · 08-12-2018, 04:02 PM

Quote:

Originally Posted by Ivylog

I agree a Allison is pretty smart when it comes to hills but for climbing mountains you often need more cooling than what it ma.y give you. You may be able to climb with the Mode red light off and let it do it's thing BUT on some curves you have to slow down so the Allison is going to upshift on you...time to manually select a gear that keeps your RPMs above 1750.

It's better to start down in the same gear (Yes, they are not all the same both ways) but it's easier to increase your speed than to try and reduce it. I like to keep the braking to 5 seconds out of every 30 which gives me a faster down than going up.

This is pretty much what we do. Watch the temperature and if climbing then a lower gear is needed. I take the transmission out of economy mode to be srue it shifts quicker. Real cold temps not as important but it will generate heat and you don't want to overheat the transmission especially. Has worked well for many years, more than I like to think about some times.