If you are going to tow with your 2008 a lot (it sounds like you do), I would highly recommend getting a bigger transmission cooler and an external oil cooler. They will help keep your temps down.Hey guys, on a tablet so this will be short. Doing a significant amount of towing with my truck. Trailer is a 7x12 v nose with a usual total wt of 5k. It seems to be working very hard on some of the longer pocono grades. Even though it pulls them at 55 65 I dont like seeing the rpms at 2750 and engine temp creep to 235. Even though I can average 10.8mpg towing so I am thinking upgrade. Looking at a 14 2500hd/duramax. A lot of $$$$$ so need some input. Ie Real world mpg on the duramax and normal op temps/mpg for a 5.3.
Thanks in abvance
Also, it looks like your put bigger tires on your 2008, while big tires look great, they take their toll on fuel economy and significantly reduce towing ability. When you put those big tires on the truck, did you re-program the ECM to tell it the new tire height? If no, your transmission thinks it has the stock tire size and shifts the transmission in that manner.
As far as getting a 2500HD with a Duramax, if you can afford the truck and can justify the cost, go for it.
The Duramax/Allision combo is one of the most capable powerplants in a 2500 or 3500 truck on the market.
For a 2014, you're looking at ~$50K and a lot more if you want the LTZ trim.