I've been shopping for CTD Ram, doing a lot of research and reading of the forums and had kind of made up my mind to try and find a 555 6 spd. After a 3 hour drive to the closest dealer that had a couple of 6 spds I was very glad to see of the 2 he had 1 was a 555 and the other a 600. After a satisfactory appraisal of my 03 hemi I spent the next 2 hours evaluating these trucks. Fit, finish and paint was exceptional on both. I then took both out for about a 40 mile roadtest, same route, same speeds and back to back. I reset the trip computer, both had less then 30 miles and travelled about 30% city, 70% hwy. The drivability of both was very good no noticeable vibration ( up to 80mph anyway), the 600 seemed to be slightly louder and had slightly better acceleration. Not much difference here maybe the extra torque will show up under load, but where there was quite a difference was in the average fuel economy, the 555 averaged 18.7 mpg compared to 16.4 on the 600. I know this isn't a scientific test and relatively short and on new engines but it does seem to back up what I have been reading as far as the 555 being better on fuel. I did decide to buy the 555 because the main reason for trading in the Hemi (which averaged about 14.5 mpg on my 6 hour road trip today) was to get a Diesel and increased mpg. I also wanted to stay away from the catylitic converter and extra emissions on the 600 although probably a better choice as far as the environment.

 

I did the same thing pretty much,I also got the 555 over the 600.

 

Some of the 600's even show 10 to 11mpg with less than 100 miles...and I have seen several 555's with the same low miles show 17 to 18mpg. It seems the newer 600's are getting better from what I am reading...that might explain why they went up 100.00 on the msrp price of the diesel option.

I think they changed something somewhere and they are getting their money back.

 

Mine has always gotten 16.2 MPG on the overhead lieometer. The first tank was 15 MPG hand calculated. Subsequent MPG checks over 8,000 miles were showing around 14. Recently, the MPG started climbing. Friday before last, it was at 16. This past Friday...17.666666. Lieometer still hanging in there with 16.2 MPG. Go figure.

I really really really like this truck. Haven't checked it towing though. A trip to the beach pulling the TT in June should be a good time to check it.

Alan

 

My truck I am thrilled with, you will not be dissapointed. My dealer well that is a different story. Enjoy that new truck, dave.

 

On the drive home from the dealership after buying my wife's 03 555 truck, the overhead slowly climbed to 19.1 over the 110 miles. It had 137 miles on it when I rolled into the driveway the first time.

Since then, hand calculated at 20.6 over the last 10 months. She's at somewhere like 13.5K miles now.

Get your cat-free 555 while you can still find one.

 

I've had my 325/600 4x4 LWB QC ST 6 speed for about 6 weeks now. I've hand calculated my mileage from the day I picked it up. With a little over 3100 miles on it my mileage has climbed from 17.4 to the last tank calculated at 19.7. Although I was hoping for better, I don't think this is too bad at all. This driving was about 10% highway, 60% rural, 30% city type driving. Living in Vermont there aren't a lot of flat roads or straight highways. Although I have not towed with it yet I will be in June. Don't be too discouraged if you can't find a 555, the 600 is doing fine by me.