I was looking for a friend at the TSB for fuel economy on 600s. To my suprise TSB 18-037-04 applies to all 600s not just ones built around Jan and Feb. My truck and engine was built around the end of April. I am debating if I should take it in for TSB 18-037-04 reflash or not. I am getting good mileage...I think. Gets around 19.0 on the intrestate driving 65 mph. Pulling a 8000 lbs trailer at 65 mph I get around 12.5 on the interstate. Performance of truck seems very good. And console MPG accuracy is very close to hand calculated (-.4). I certainly do not want to fix what ain't broke. But then again if I can improve from 19.0 to 20.0 then I would do it! What would you guys do and has anyone reflashed a late model 600?

Thanks!

 

Dont do it! With those numbers it is asking for trouble.

If you get good mileage and you DO, and the overhead is even in the BIG BALLPARK, then I recommend against it.

I had it done and dont really think anything changed except the overhead readout is now off on the high side. My engine build date is 3-15-04. My mileage on interstate at 65 is about 15.5 and it still is after TSB.

You ask me and thats what I think.

 

Roger that! I think you are right. I sure don't want to make it worse! I guess sometimes you gotta know when to fold'em and know when to run.

 

mine was about 19.5 mpg at that speed on the interstate previous to the tsb after its up over 21 mpg i took my chances and it worked and with the price of diesel i'd do just about anything to burn less of it

 

Papaperk
I was also getting good mileage (15.5 town 18 highway @65/70 prior to flash) After the flash, 16.5 town 19.5 @ 70. It appears that we have the same truck, however mine is a 48RE, and has a 01/04 bulid date. My vote would be to go for it. Besides you wouldn't want an auto to get the same mileage as your 6-shooter!! Good luck in your decision
Odie

 

Hmmm....very intresting guys. I am going to have to think about this one!

 

Get it done there are beenfits besides the fuel mileage....smoother, less ticking/pinging, etc.

 

That TSB applies to specific engine serial numbers and build dates. I can't tell you what they are though. One of the numerous threads about this TSB has a copy of the TSB attached.

The first thing the service writer did when I went in for the flash was go out and retrieve my engine's serial number. If your serial number isn't in the affected range then I would suspect the service department will turn you away.

 

The reason the dealer checked the serial number, is to see if it was an early build "600". Serial numbers 57130285 thru 57246361 where used in the early builds. These motors should have been flashed earlier (TSB 18-007-04) however, some where not. The new flash (tsb 18-034-04) incorporates the old flash into the new flash. The flash is available to every engine built between 12/10/03 and 08/17/04.
Hope this helps everybody
Odie

 

Yes my engine is within the build date and serial number range. Now I gotta decide if it is worth the gamble. I would love to be getting better mileage. But I sure don't want to screw it up!

 

Had mine done about three weeks ago at first thought it was great now that I have had it for a while seems like I have noticed a little less torque at wide open throtle from a stand still and the milage is about 1 mpg better but the overhead is off about 2 mpg more than hand calcs before it was within .4 mpg . 1 mpg is not worth the gains that I have seen seems like someone is playing us 600 owners as fools ! So far I am not impressed with Dodge or Cummins! just my 2 cents worth !!!!

 

I had the flash done, and my overhead is much further off than it was before. But the actual hand-calculated MPG is up about 1 mpg both empty and towing under most circumstances. Still plenty of power, but it is different. The boost seems to come in more smoothly than before..... Hard to explain

I rarely make highway runs empty, usually towing my car trailer, but the same trip that netted me 13.6 with the trailer (mixed highway and 2 lane road) got me 14.4 hand calculated last time. On the highway empty I got a best of 18 once before @ 70 mph. Since the flash I've gotten 18.2 a couple tanks @ 72-73 mph. Also, one tank that was no so good @ 16.9, but had a terrible headwind and that included a couple of runs up to 90 mph and generally cruising @ about 75, so I'm not that upset about it.

Overall, I'm glad I did it.... so far.

 

Sam... how heavy is your trailer? Is it a box or flatbed?

 

My trailer with the car comes in a just over 5k, open flatbed type, but I also have a tire rack that adds a little drag (not bad, but does add some).

That trip I was talking about is 40 miles of Interstate (where I'll do at least 70), 20 miles of normal 2 lane, and about 15 miles of twisty ***, 40 mph average up and down backroad.

My 6.0 2500HD got me 11 on the same route while towing the same car on the same trailer.