Cummins ISL 9 with Alison 4000 6 speed.

[pointrow]

2014 Providence 42p pulling a toad. Combined total weight about 42000.
Traveling on 70 through Utah. This rig really seams doggy. With cruse set on 65 it will pull down to 40 on evan the moderate grades. It won't shift down but hangs in there till I manually shift it, Evan then it won't do 55 mph.
I'm real disappointed. Is this normal and as good as it gets?
BTW the transmission has the latest FLASH.

Thanks
pointrow

[Ivylog]

wolfe10 wrote:
1500 RPM is 58 MPH in 6th gear per GPS.

Thanks. 55 is about as slow as I can go in rolling hills and keep it in 6th. On level ground I have to get up to 55 before mine will go into 6th. I can then slow down to 50 but anything slower and it will go to 5th.

[wolfe10]

1500 RPM is 58 MPH in 6th gear per GPS.

[Ivylog]

Brett, I'm curious what speed you have at 1500 rpm? At 65 I'm turning 1750 so if we have the same axle ratio... that's about 55?
OP, are you saying you got down to 24 MPH on 70 before the Eisenhower tunnel? What boost pressure were you showing and what rpm? It does not take much of a hill for mine to downshift into 5th and 2000 rpm with the mode on to try and stay at 65.
In rolling hills like on I-75 north of Macon GA I've found it's better to turn the cruise off and at the bottom of the next hill be at 70+ and accelerating. This gets me over the next one at a little less than 65 and usually still in 6th. If I leave the cruise on and wait for it to start accelerating I lug down and at the top I'm at less than 60 in 5th.

[luvlabs]

You simply need to learn to drive within ithe engines power band and forget trying to keep up with the cars. The ISL climbs very well at 2000-2200 RB so learn to use your gear selector and throttle to keep the RPM there. The engine wil run cooler and you will get up the hill.

[wolfe10]

Your peak torque RPM is at 1,300 RPM. Do NOT run at high throttle positions below that engine speed.

When climbing with the same drivetrain, I pretty much run at 1.500 RPM. Same RPM for cruising-- it gives the best MPG.

But, your coach is a LOT heavier than mine, so you will not have the same performance.

[pointrow]

Today I watched the shifting pattern more closely and it is shifting down as low as 24 East through Loveland pass on 70.
Feels like it's dragging an anchor.

later
pointrow

[Passin_Thru]

Manually shift it with the button instead of letting it lug down.C'mon, on 3, you can do it! Don't let it lug to 1100 RPM.

[pointrow]

Ivylog wrote:
I'm a little surprised you have a 4000 tranny as most ISL's came with the 3000. Not downshifting between 65 and 40 is a programming problem... probably because it's programmed for 500 HP.
My combined weight is over 42K and I can climb most mountain passes at 40 in 4th without manually downshifting. On a long climb I will manually shift so if I have to let up on the throttle for traffic it does not upshift. I use the Eco Mode for rolling hills but not for mountains.

My bad it is the 3000.
thanks

[Mr_Mark1]

Our '08 Dynasty with the 425 hp Cummins ISL was not the fastest up the hill. We weighed 40,039 lbs. at the last weigh-in. It may have been slightly more after we put a REAL mattress in it. The air mattress was junk (no sleep number for me).

We went slow up steep grades. The incline going east to Denver slowed us to about 37 mph. Temp stayed slightly above normal and we made it. The 425 has 1,200 lb. ft. of torque. Our new 500 hp Volvo has 1,750 lb. ft. of torque and at 54,000 lbs., it's a jack rabbit! We will go slow up hills but better than our previous.

MM.

[Blaster_Man]

Agree with Ivylog...I think you'll fine it's an Allison 3000, that's what all ISLs that I know about have. As for the power loss, check for a turbo leak around the hose/fittings. You'll have normal RPM, but a power loss.

[Ivylog]

I'm a little surprised you have a 4000 tranny as most ISL's came with the 3000. Not downshifting between 65 and 40 is a programming problem... probably because it's programmed for 500 HP.
My combined weight is over 42K and I can climb most mountain passes at 40 in 4th without manually downshifting. On a long climb I will manually shift so if I have to let up on the throttle for traffic it does not upshift. I use the Eco Mode for rolling hills but not for mountains.

[DSDP_Don]

"pointrow"......In my previous coach, an 05 Diplomat running 37000 pounds when towing, my 400 ISL, chipped to 450 HP would pull the I-5 grades in California and Oregon in 5th gear at 55 mph plus. I once topped the Baker grade going to Las Vegas (coach was 36000 pounds at the time) at 70 mph.

Fast forward to my new coach, 2014 ISL 450 that weighs the same as you when towing and it's no where near the hill climber my Diplomat was. On my Diplomat, I would just drop into 5th, with the cruise control on and climb. I do the same with my new coach, but it will start to lose steam about half way up. I find I have to get more of a running start and keep working the throttle to try and maintain a reasonable speed. Most of the grades I was climbing before at over 55 mph, I'm now doing between 45 and 53. I try to stay around 1800 -1900 rpms for power. I never had to drop the Diplomat into 4th, but I do with the 2014 at about 40 mph.

Now here is some good news. Mine was really doggie until it hit about 10000 miles and the power started to improve. I'm now at 12K and found on my last trip it had even more power. I don't think it will ever compete with my Diplomat, but it's getting better. I figure it will keep improving until it reaches about 15K.

There is an engine chip (DigiCR) that I added to my Diplomat that can be added to the new DEF engines. It changes the fuel timing, but doesn't leave an imprint on the ECM and reverts back to stock settings at wide open throttle. It worked well on my last coach. I will probably wait until I have 20K on this coach before adding it on.

Sooooo.....with all that said, you're coach is doing what it should. You may want to manually drop to 5th and turn off "Economy Mode" at the base of the grades for better performance.

[wallynm]

what elevation, and what size engine and torque ratings? Clogged fuel or air filter?? turbo not working properly?? if you are at 42,000 then this may be all you get.

The ISL9 features common technology with the Heavy-Duty ISX15 and ISX12 for exceptional performance. Common components include the XPI fuel system, a high-capacity Electronic Control Module (ECM) and the patented Cummins VGT™ Turbocharger from Cummins Turbo Technologies. Ratings range from 260-380 hp (194-283 kW)

[JR45]

In the (ECONOMY MODE)it can turn into a dog on some grades.It can make a BIG difference in rolling hills. If you are in rolling hills and regular mode (particularly with the cruise control on), it is common for the transmission to shift down to 5th on the uphill and back to 6th on the downhill. Repeat this process hundreds of times. In economy mode, you will stay in 6th gear unless the hill is so steep or so long that the engine can not pull it without dropping below peak torque RPM.
Every time you start the coach, the transmission is in regular mode. This is the default setting. IF you push the mode button, it goes to "economy mode" AND the light illuminates, your coach may of had the default settings changed.
JR