reviews or opinions on Cummins ISX
 

Would appreciate any reviews or opinions on Cummins ISX. I am interested in getting one. Also, it has auto transmission (Freedom Line).

Thank you.

The truck I bought has both (Cummins and Freedomline) Had 500k miles when I bought it 7 months ago and I have put 80k miles on it.

The ISX is ok except the parts are expensive to replace. I replaced the EGR valve and Turbo a few weeks ago and it cost $3800.

I get good fuel miles and plenty of power with the ISX

I have driven both the Freedomline and the Ultrashift and the Ultrashift is way better. The Freedomline shifts sloppy to me compared to the Ultrashift. The first week I had my truck the clutch went out on the Freedomline and it cost almost $4,000 to replace.

I have a 2006 International 9900 with a 500 HP ISX.

My two previous trucks had Cummins N14's.

The ISX is a significant improvement with power, fuel economy and with hold back on the Jake.

I run 80,000 lbs, but have had it pulling chip trains that grossed out over 140,000. In the fleet it was leased to, it outpulled every other truck they had, and every driver saw it when we passed them loaded on the big hills. We could pull one gear higher than most other trucks, especially the Mercedes engines. We could decend one gear higher than the Cat engines and still not touch the brakes on the 8% grades.

It has 80,000 miles on it, and I had to do the Turbo just last month. It cost about 1,000 as the new ones have a kit available for them. I paid over 3 grand for a turbo on the N14.

I like it. If I where to purchase a new tractor, I would get another one.

I had 2 KW T2000's with auto and an ISX in each. Ran 2250 miles each week with 40,000 to 44,000lbs of paper. In the summer I avgd about 7.2 - 7.4 and the winter around 6.4mpg. of course, I didnt idle the truck as we had bunk heaters and in the summer I was north of the Great lakes so didnt need the A/C. I liked the power and never had a problem with the engine in any way. And once I got used to the Autoshift I loved it.

2008 model year, 486 hp, T660:

Fuel mileage is disappointing. Toronto to Syracuse at 80K gross then back to Toronto empty resulted in 5 mpg. Doesn;t seem to matter if you're driving 72 or 62 mph. Pulls good though.

Sounds very low. I get 7.5 mpg (imperial gallon) running 75,000 in the mountains.

Wish my signature 600 would have done 5.5 mpg. I'd have kept it. AWESOME engine.

UPDATE: It now has a new turbo at 120,000 miles. Covered by warranty, but still. What a joke.

I’ve got a 450HP ’06 ISX with an Autoshift (only because the wife is too lazy to actually manually SHIFT a truck). I love the fuel economy compared to my C-15, but if I could get my old ’03 500HP C-15 back and have the same 6.75 mpg I’m getting now I’d do it in a heartbeat. My old CAT would way out pull my new truck. Not to mention that I’m bothered by Cummins’ belief that 35 psi oil pressure is adequate… every time I start my truck up I wonder what the heck they were smoking when they came up with that one.

Besides the fuel economy, the only positive comment I can make about the ISX is it has one hell of an engine brake. Cummins doesn’t use a Jacobs Vehicle Systems engine break, but rather their own integral engine (they call it an “interbrake”) brake that they claim offers the same braking horse power as driving horse power. I’d have to say that they are accurate in their claim. We run out west a lot (and up and down I-5) and I can probably count on one hand the number of times I’ve had to use the service brakes when descending a hill in our new truck.

My '01 ISX has nearly a million on it, though it had work done on it at 650,000 before I bought it. It's been great for me, I add no oil between changes for one.

This is what I want to say, though: A $9.99 12volt air compressor can really improve the quality of life for an ISX owner. If you don't know why, just ask, I'll elaborate! :smokin: Man, I love that pump!

I'll Bite!
 

Ok, I'll bite. Why do you love that pump?

I wasn't trying to be a jerk, I figured other ISX owners would have them, too.

That $9.99 12v pump has saved me a service call more than once, last time I think I was at a fuel island and the truck wouldn't start. My ISX has one of these visible, "glass" bowl fuel filters, and they can lose their prime.

I've changed my fuel filter many times, but one time I just wasn't getting a good seal for some reason I know not why. So with the pump, you pressurize your fuel tank, loosen the cap on top of that bowl so the air escapes, and perhaps loosen the line going into the fuel pump so that air can escape there too- voila!!! A few bubbles here and there, tighten it back up, the prime is back! You can watch the fuel rising in the fuel filter housing as the pressure builds up.

To hook up the air, I pull this lever under my cab that shuts off flow from one of my tanks. On the other, there's a drain tube coming off the top, the nozzle fits into that drain tube perfectly. I watched the service guys do it a couple of times, that's how I learned.

Hey, that is a really handy tip. Thanks.

I don't think anyone thought you were trying to be a jerk, I know I didn't. :thumbsup:

I dunno, lowrange, my '06 ISX is self priming. I had a blocked vent tube which caused me to run one tank completely dry while the other tank remained half full. Before I figured out what the heck was going on, I ran the line completely out of fuel. Once I figured out what had happened, I just blew out the clogged vent tube, waited a few minutes for the fuel to drain into the right tank, and started her up and drove off. I had to crank it for about twenty seconds and it sputtered to life and then died, but the second time it started up and ran with no problem.

I don’t carry an electric air pump, but I do carry 75 feet of air line fitted with a glad hand adapter and a quick release air chuck and blower. Also have one of those cheapo air blowers that attach to the seat air line. Not only is it good for blowing out the cab of the truck but it also is the only thing we’ve found that works as punishment for our cat. When he starts biting or clawing, all you have to do is lean down like your going to grab the blow gun and before you can get it in your hand he’s in back hiding under the covers. Won’t come out for at least 30 minutes after that.

For those with the ISX that are disapointed with the fuel mileage, as I was, then you might give this a try....

On a COLD engine, turn the key on without starting, then wait at least 10-15 seconds then unplug the lower plug on the EGR. The ECM will close the valve during the wait time, then the unplug will leave it closed. Will usually only throw a code. Usually no check engine light or limp mode, depending on which truck the engine is in.

The results? How about up to 1 mpg better fuel mileage. I did this some time ago. I have averaged about .8 mpg better than before I did this. The engine runs substantially cooler on hard pulls. No hp or torque gains that I can tell. Just that the engine runs smoother, less soot and smoke, and better mpg.

Simple, cheap modificaton. Better than investing in the slew of addon stuff that normally doesn't seem to really work as advertised.

What year is your ISX? Does it have a DPF?

'06 ISX... no DPF

'08 with a DPF here. Sorta wondering what the EGR trick will do to the DPF. HAven't found anyone that's tried it yet.

09 porstar. 450 hp isx, ultrashift. with 135k. been in the shop once "bad after-treatment injector and a pluged crankcase filter" hate the truck but love the isx. pulls better than the volvo d12, d13 and detroit d15, better jakes and better mpg.

...put less soot in it.

I don't yet have a DPF engine yet, but alot of problems seem to be the norm...

I believe Bob has alot of knowledge about engines and would like to know if he would recommend this EGR shut off for trucks that idle alot ?

The few times I have heard of someone with a DPF equipped ISX, doing the EGR trick didn't work too well. Seems the ECM has a real issue with it. There is so much going on with the different sensors, it didn't like the EGR being unplugged. On the others, I have heard of some throwing a CEL, but the engine ran just fine. On mine, it does throw a fault code, but I had the engine put on the Cummins diagnostic and the code was only for an electrical circuit disconnect. No CEL. Have had the EGR unplugged for approx 100,000 miles and have no desire to plug it back up. My Cummins dealer could really care less. They never have pitched a fit whenever I took it to them and they just ignore the unplug. Had a couple of warranty issues (not related to the emissions), and they honored teh warranty every time, no question, even with the EGR unplugged. It just went out of the 500,000 mile warranty, so that isn't an issue anymore.