960 express cruiser... wheres the power?

FREE TO FAIL

Seasoned Expediter
I recently purchased a 2006 sterling express cruiser with the 330 hp mercedes engine with the allison 6 speed. nice truck but quite frankly a dog on the road.... truck has 300k on it but seems to run fine. My question is wheres the power? I was hauling about 7.5k on i -44 in mo. and the truck was losing about 10 miles an hour climbing. fuel economy wasnt that great either. I was wondering what kind of rear axle ratio is appropriate for these trucks? additionally is the allison auto that big of a power leach? any ideas what it could be? I would appreciate any info on these units.
 

davekc

Senior Moderator
Staff member
Fleet Owner
Probably a 4.3 rear end. Mercedes aren't exactly a power house with the 330. Probably between that and constant EGR problems, they got scrapped in favor of the Cummins.
I would say the engine is the bigger issue rather than the Allison assuming it is set as a 6 speed.
I don't believe you could go to a 3.9 as that setup wouldn't have enough torque on a grade.
 
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piper1

Veteran Expediter
Owner/Operator
When you get to the hill, how fast are you going and what RPM?

When it "dogs out" on you, what MPH are you at and what RPM?
 

FREE TO FAIL

Seasoned Expediter
near as i can recall i was running about 70 at around 2000 to 2100 rpm. but the condition seems prevelent at 55 to sixty on any type of grade just no pedal available. seen the rpms spike at around 2300 in the alledged passing gear but no real gain in acceleration. mercedes must be using a different way of calculating hp cause 330 should be plenty when grossing under 29k. mercedes is in alot of buses and rvs should be an ok motor?
 

usafk9

Veteran Expediter
That truck should have plenty of power with that weight, unless you pack that sleeper like my wife does ours.

Seriously, that engine/tranny/RE combo is nice, IMHO (I concede the EGR issues). If it were me, I would get it into a shop and find something wrong. Maybe dyno and find out how many HP it really produces.

My very humble and somewhat inexperienced opinion. We drove that model truck, and it plenty of power.
 

piper1

Veteran Expediter
Owner/Operator
near as i can recall i was running about 70 at around 2000 to 2100 rpm. but the condition seems prevelent at 55 to sixty on any type of grade just no pedal available. seen the rpms spike at around 2300 in the alledged passing gear but no real gain in acceleration. mercedes must be using a different way of calculating hp cause 330 should be plenty when grossing under 29k. mercedes is in alot of buses and rvs should be an ok motor?

Well, at 70 you are pushing a lot of wind and wasting a lot of hp to do so but I will save you the speech.

If you are going to keep this truck for a few years I would re gear the rear end. You will have better performance if you get it geared to be at 2000 rpm at 60-63 mph. You may be able to achieve this with a tire size change depending on what you have on it now.

HOWEVER, if you want to keep running at 70 mph the gear change will hurt your mileage, but running at 70 is also killing it as it is now.

If you are serious about getting some performance and fuel mileage out of it, and are willing to slow down, PM me and I will run the numbers for you.
 

LDB

Veteran Expediter
Retired Expediter
I had a 2005 960. Max setting that year was 300hp and I think it was 880 torque but can't recall for certain. I got around 9.5mpg with it. I usually ran it around 1800 for about 62-63mph. Running 70, which I did during a family emergency, dropped it to about 8mpg. Speed is your worst enemy. It takes your money and gives back nothing in return. Running through MO. in mine I don't recall dropping as much on the hills as you did, more like 3-5mph maybe. Good luck figuring it out.
 
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