[BIG JEEP on 44's]

i drove a cut back c-15 at the...W...for ove 2 years with an 8 spd , And despite it being cut back it pulled hills pretty well...Now I have an 05 t-600 with a Red top in it governed at 72mph , And even pulling an empty trailer up small hills it catches asthma infact I'll run by a Werner with an empty trailer just to watch him pass me on a small hill ,and there is a seal on his trailer door ,so I know it's not empty ...this ISX has about 600k on it ,and I think it might need an overhead and it has a 10 spd behind it which in my opinion sux on hills because the rpm gap between 10th 9th ,8th are huge ...So is it just the transmission/engine combo and possibly the engine needs a tune uo...or are these engines really this shy on torque .

[Jumbo]

My first guess is the tranny. I never cared for a ten speed. If you had a 13 I don't think you would have this problem

[Uturn2001]

It could be anything from how the truck is spec'd and/or set up to a mechanical issue.

If there are other drivers in your company with an identically spec'd truck I would speak to them and ask how theirs do on hills.

[JR OTR]

I have driven my '06 T600 with a cummins for more than a year now and you aren't imagining things. Compared with Cat engines they simply do not generate as much pulling power going up hills, especially with heavy loads.

On the other hand, on flat ground (I mostly run the midwest) they do seem to get better fuel mileage and my engine burns zero oil... I bet I consume more oil checking the dipstick than the engine uses. Very reliable, too.

[tweety bird]

If you can get in to Cummins in Avondale (Phoenix) Arizona... they are the BEST Cummins shop in the country. I say this after many, many bad experiences (and we only take the Cummins to Cummins- we don't take it anywhere but Cummins if there's a chance it might be a Cummins issue). They have a dyno and good mechanics- they also stand behind their work 110% which is unusual.

I'd normally want to go home and have work done when I'm at the house- Ohio (and a bunch of other states) doesn't charge sales tax on parts etc if you have an ICC # (as in- leased to a carrier or have your own authority). But I'll pay the higher rates, be away from home and pay the sales tax gladly if I get good, quality work in return.

Anyway- what engine do you have? 565? We have an '05 565 with 355 rears and we have consistent 5.2 mpg. I swear that whenever we run heavy (80,000 and above) that truck pulls better. If we load and hit a hill and pull it like there's no tomorrow, we stop in at the next CAT scale to check it out- never fails.

Weird, huh?

[Rev.Vassago]

Originally Posted by tweety bird

We have an '05 565 with 355 rears and we have consistent 5.2 mpg. I swear that whenever we run heavy (80,000 and above) that truck pulls better. If we load and hit a hill and pull it like there's no tomorrow, we stop in at the next CAT scale to check it out- never fails.

Weird, huh?

Not weird at all. I've found the exact same thing with my 565 Cummins. If I have a 20,000 lb load on, it seems to fight with hills. If I've got 44,000 in the box, it pulls like a champ. I think it craves the challenge. :wink:

For the record, I'm running a 565 with 3.55 rears and an 18 speed. I get about 5.75 out of mine when I'm not constantly idling.

[tweety bird]

Originally Posted by Rev.Vassago

Not weird at all. I've found the exact same thing with my 565 Cummins. If I have a 20,000 lb load on, it seems to fight with hills. If I've got 44,000 in the box, it pulls like a champ. I think it craves the challenge. :wink:

For the record, I'm running a 565 with 3.55 rears and an 18 speed. I get about 5.75 out of mine when I'm not constantly idling.

That's exactly how it is! If we're empty or really light, it takes forever to get up a hill.

[Bigmon]

Originally Posted by tweety bird

If you can get in to Cummins in Avondale (Phoenix) Arizona... ?

Is that the Rocky Mountain Cummins place?

[BIG JEEP on 44's]

welp that t-600 is now the past and i got an 08 t-2000 with a 475 cat in it still got a 10 spd , but it pulls much better and has that deep throaty sound i like ...i 'm averaging 6 mpg right now .

[Malaki86]

The Volvo I'm in now has a 400hp ISX. It's one of the best pulling trucks I've ran in a long time. We run heavy, normally within 500# of gross and most of our running is into and out of West Virginia. I can pass soooo many trucks on the hills that it literally shocks me, especially when whoever I pass says something on the radio to the tune of "You must be running light". When I respond that I'm almost grossed out, they're shocked because they're only pulling 25-30k.

This happens quite a bit.

Now I wish they'd change the tranny from a straight 10 to a 13spd.