If U were spec'ng a truck for fuel mileage...

Dan, I agree with you completely that this setup would not be good for a heavy haul situation such as you guys run over there. Over here where the loads typically gross between 60-80k, it would pull the load sufficiently. Keep in mind that using a direct drive(1:1 ratio) transmission gear such as 16th in an 18 speed box matched to the 2.64 rear gear is the same final ratio as a 10,13, or 18 overdrive in the highest overdrive gear matched to a 3.55 rear gear.

There is nothing that says you would have to run in 18th or even 17th to run higher speeds when heavy. You could always run in 16th or 17th(depending on speed) at a higher rpm to maintain momentum.

I don't claim this to be a perfect setup for everybody. If I was going to be heavy all the time, I may not use this setup. The whole point of it is the flexibility that it offers.

The trucks that I have seen for sale used with this setup were clearly special ordered, owner operator spec'd trucks. I have only talked to one guy who had a truck setup like this and had his truck for sale. He ran a dedicated lane from Atlanta area to the west coast and back pulling a reefer. His loads were 60k gross outbound and 65-80k coming back(produce). He seemed to like the setup for the same reasons I stated, the flexibility. He actually was taking ownership of a new truck that he ordered with identical specs.

 

I have no clue what you think you're talking about when you say it won't pull a hill. You would just have to adjust your driving habits a little bit. You are right that there is no way it will hold 18th or even 17th in a steep pull. Just means you will be dropping gears a bit quicker. Once you get down to 16th though, it will pull just as good as a 3.55 ratio would.

 

I didnt eleborate on what i was meaning..

To hold the engine in an RPM band where it would be making sufficent TQ hp to utilise the upper gears, you would be eating the road up.

Not sayign its not good, but you would need to be enjoying open country without any Bears..

i seem to recall reading something on the eaton site about constant running in a gear other than top.. although that may have just been the first OD.. got nfi why it would matter tho...

 

pre-04 detroit, 3:55, 18spd you dont have to use'em but its sure nice to have them if you need them...

 

I was always told a 10 speed would be ideal for fuel mileage with a Detriot or Mercedez. These are the only motors I have heard of getting any fuel mileage lately. I would assume your gearing would have to be set up as well and I have no clue on that aspect.

 

Well i can tell you my 03 t-600 kw 13spd 3:55s gets 6.1-6.5 with a very very tired 890,000 mile cummins 475 hp with an 86,500 gross weight tanker going cheyenne wy to wray co 6.5 mpg and 6.1 same weight cheyenne wy. to torrington wy.


Both times headed out with topped off tanks and fuel up again at destination, this is no idle time and 65-70 mph on secondary roads.

 

The non-dpf ISX's with a direct drive 10 speed, 3:55 rears, and 22.5 lo pros will easily get you 6.5 mpgs and puts the rpms just right for 70mph at 1500.

 

Yeah run it in 16th gear all the time and that trans will run hot as ####.

Here's the ultimate set up volvo truck, volvo engine, volvo trans, volvo rears, volvo tires, volvo rims, volvo paint. Trailer volvo trailer with volvo reefer. With this set up you will never have to buy fuel again but rather it will gain fuel in the tanks rather than burning it.

 

You forgot to add the air tabs on both the truck and trailer and as many turbo3000's you can fit between the tanks and the engine. As for the fuel that will be poring out of your fuel tanks you'll just have to find someone with a W900 or 379 to give it to.