My F-350 was flashed a couple of weeks ago right before a trip towing the fifth wheel from OKC area to Eastern Oklahoma (238 miles). I have made this trip a couple of times before already this year.

The fiver GVWR is 16K but actual weight is just under 14K. Previous trips I would like to run about 60 MPH but transmission would downshift going up just about any hill. Running the speed up to 62-65 MPH and could make it up most hills without the transmission downshifting.

Okay, to the point of the post..... This last trip I could run 60 MPH and the truck could pull all the hills w/o downshifting; both on way there and the return trip.

Now the only question to attributing all of this to the latest flash is that I also replaced all the tires on the fifth wheel with Goodyear G614 load range G with 110psi inflation. So I suspect my rolling resistance is better than it was with the previous Nankang Mission China load range E @ 80psi tires. (two failed on previous trip).

So has anyone else noticed a towing improvement with the lastest flash? I'm wondering if my improvement was the new flash or more attributed to the tires.

I have to say with the new flash and the message display indicating when it is cleaning the exhaust filter that usually I miss that brief message but it is nice to run through status to confirm it is in regeneration; I just wish they would have moved it to the top of the list.....

Bob

 

How many miles on the truck? Could be the motor is loosening up, and your mileage might increase too. Just a thought, it could be the new flash too.

 

Could be the flash? But if I was to bet on it I would say the tires!

 

my vote is the flash, based upon most peoples comments that had the job1 and 2 trucks. Mine is a job 3 so what you are seeing is what I normally see.

 

I don't think it is the mileage as the previous trip was only about 8 week prior....

Son-in-law didn't believe me when I told him I made the trip following him w/o any downshifts; he was pulling their fiver with 04 6.0 PSD. Their fiver weighs less.

http://www.everytime.cummins.com/***...Whitepaper.pdf

See pages 6, 15, & 23 at above document with respect to rolling resistance of tires. Granted document is oriented towards big rigs but some good info just the same.

Thanks for replies,

Bob

 

Bob,
I would bet it's the new flash that's responsible. I just pulled my fifth wheel over 1000 miles and only had the truck downshift on two occasions. The trip was from Indianapolis, Indiana to Des Moines, Iowa and back. I was pulling around 14,500 pounds. The terrain in Iowa was mostly rolling hills and instead of downshifting, the boost gauge just kept climbing to around 32 pounds but never felt like it was straining. My truck is a build 2 with the latest flash installed a couple of months ago. By the way, average fuel mileage was 9.5 mpg hand calculated all at 60 mph. Are these great trucks or what?!

 

What is the TSB# for this flash? I want to be able to see on my dash when I go into regen!

On your orignal question I stll belive its the tires. simple test get a wheel barrel load it up, push it around your yard. Now same load same everything execpt empty some air out of the tire and see how hard it is to push around.

 

TSB 08-13-3

TSB 08-13-2

Most dealers are not going to reflash just because you want the latest flash.

Mine was reflashed with reference to TSB 08-13-3 and because of excessive black smoke (their words) in response to my complaint of cracked DPF.

I also complained about the aggressive "resume" of cruise control when resume is pushed several MPH below original set cruise speed and they could not find any problem; the latest flash corrects this problem.

I like this latest flash. Most of the time I miss seeing the momentarily displayed message (they should make it chime too) that it is "cleaning the exhaust" (or complete for that matter); but when I suspect it is in regen I can push the buttons and it will confirm that it is indeed in regen.

Truck seems to run smoother with this flash.

No regrets,

Bob

 

I don't know if it is the flash or the new tires with respect to my original post; but I certainly agree these are great trucks. It is a pleasure to comfortably tow with this truck; the performance makes any towing trip more relaxing just knowing she will do all you ask of her w/o feeling like you are pushing the limits or stressing the drivetrain.

Yea, I really like this truck

Bob

 

Yes Bob these are great trucks.

I got my JOB1 reflashed 3 weeks ago and feel that something changed in the transmission... and I do not tow. I still have the original tires

 

Thanks bro, I also want to know when in goes into regen.