I got the 4.7 and I had something in the a/c break but had it replaced. I got the fuel pump replaced at 2 k miles. It currently sits with 11k miles and nothing has gone bad......yet. It's a r/c 06

 

I have a little over 100k on mine. The only problems I faced where my tranny was going at 50k (due to towing with the lousy 3.55 gears at that time), andrunning higher engine temps than normal, but that was due to a clogged cat. Other than that motor wise nothing bad. My truck is still running strong, and within a few weeks cams are being put in. These motors are very strong reliablity wise, I know a few people who have hit or are close to 200k on their Rams, without motor problems but the normal wear and tear.

If possible try to stay away from the 3.55 gears, those do not belong in our trucks. I still would opt for the hemi, if he could., more power and better mpg with or without the mds.