LMM road report

[50+]

I thought I would share this towing info from a trip I just made to Cody Wyoming and back, with my new 08 LMM. I was pulling my 20' Gn trlr with 5 horses. I weighed in Cody and tipped the scales at 19,660 lbs. My speed varied from 50mph to 75 mph. Total miles for the trip were 2482. I used 230.9 ($$$$ !!!) gallons of fuel for an average of 10.5 mpg. My mpg ranged from 9.3 to 12.8. The 12.8 was a short run of only 49 miles, I topped off cuz wasnt sure what would be open at 2 am. I had one run of 181 miles that got 11.8 mpg, but my speed was at times only 40 mph because of icy roads and poor visibility, in western Nebraska. The 9.3 was hilly terrain with 6th gear locked out. All mileage was hand calculated. Overall I am pleased with the mileage. I started out with only 1705 miles on the truck, and had visions of 7 or 8 mpg because I was pretty heavy. Plus I didnt know how much of a factor the dpf would play into the mpg, from what I've read. I was extremely pleased with the power, and I am bone stock. It was able to maintain 6th gear on some grades I didnt think it would. As far as the dpf goes, I'm sure it regenerated numerous times, but I didnt notice any of them. On a similar trip last September with my 05 LLY I averaged 11.6, but with just two horses. So, my personal opinion comparing the LMM, to the LLY, it appears The 6 speed Allison may offset some of the fuel lost during regeneration. In a long run anyway. At 70 mph the 5 spd is turning 2200 rpms vrs 1700 in the 6 spd. Time will tell.

[D_R_C]

Just my opinion,I would keep the RPM`s between 2000 lowest and 3000 hi, towing especially on grades.
Towing @ 1700 I feel is at the point of lugging the motor.
I run mine in 5th most of the time towing and when on flat ground 6th is ok.
Again this is my opinion.

[More Power]

Thanks for your report! Your loaded fuel economy sounds pretty reasonable to me. I agree with D_R_C about towing heavy in 5th instead of 6th unless you've got an easy pull. And, I doubt the system did much in the way of active regen because of the load and higher overall exhaust temperatures. It'll passively regen when the exhaust temps are high enough - like while towing.

Thanks again,

Jim

[Showgood1]

So if your generating enough heat when loaded to clean the dpf then how does the computer know when to regenerate otherwise?

[D_R_C]

So if your generating enough heat when loaded to clean the dpf then how does the computer know when to regenerate otherwise?

From what I`ve been told when the system notices enough back-pressure starting to clog-up the regin will start.
They say if you drive a lot of highway miles the re-gin will be less than if you do in-town stop and go driving.

[50+]

I cant disagree about runnuing in 6th in hilly country or when a long grade will drop you into 5th. I experimented a bit when I started out because I've been quite curious about how the 6 sp allison works when towing since it came out in 06. On this trip as I went along I would lock 6th out when I was pretty sure It would shift on top of each grade. Then tap it up into 6th on a good flat run. Nevertheless the power is great and it impressed my buddy who rode with me, AND he's a Ford guy!

[Runaway_Dmax]

I cant disagree about runnuing in 6th in hilly country or when a long grade will drop you into 5th. I experimented a bit when I started out because I've been quite curious about how the 6 sp allison works when towing since it came out in 06. On this trip as I went along I would lock 6th out when I was pretty sure It would shift on top of each grade. Then tap it up into 6th on a good flat run. Nevertheless the power is great and it impressed my buddy who rode with me, AND he's a Ford guy!

What I noticed from what little towing I have done (about 700 miles) that if the truck is less than 60 mph, it doesn't even shift into sixth gear.

I think your mileage is pretty decent for what you were pulling also.

[50+]

Your correct. It doesnt shift into 6th until you reach about 61 or 62 mph. And also the Allison will not shift into 6th if it senses a hard pull.