I'm sorry, but this is going to be long. I need some serious advice though! We recently upgraded from a 2003 2500HD 8100 Chevy truck to a 2004 1-ton dually duramax diesel. We did this because we have been told they out perform the 8100 in towing and fuel economy by a lot. We have a 36' toy hauler that we tow to the Dumont and Glamis. The 8100 ran great, but got horrible gas mileage. So we traded it in on the dually. The dually ran excellent for the first 2000 miles. The first time we tried to tow our fifth wheel, completely empty, so it weighed 9,000lbs, the clutch fan went out and over heated the engine. We immediately took the truck to the dealer, and they replaced the fan. We tried to tow our trailer unloaded again and the truck had no power and would start overheating unless we let off the gas. Mind you this is on a 1% incline. We could not get the truck above 65mph, and the fuel economy was worse than the 8100. We are getting 2-4mpg towing an empty trailer at 65mph. It shifts into 4th gear all the time while we are in cruise control. And when we are not towing, we have not gotten above 14mpg. Also after we got the truck back from the dealer, oil started leaking from the intercooler. It ran all down the frame, and one time when we started the truck it pucked out about 1/2 a pint of oil. We have taken the truck to the dealer numerous times and they keep giving it back to us telling us there is nothing wrong with it, and that everything that is happening is normal. We can't even tow our trailer, which is why we bought the truck! The last time we gave them the truck, they came back and told my fiance that we had oversized tires on it, and that is what is causing all of our problems. We put new tires on the truck the second day we had it, and they are 0.4" taller than what came on it. We just put some tires on it that had a little more tread on them for going over the sand. We know they are full of sh*t because the literature they gave us about tire size also had the same exact truck as ours with single rear wheels, and it comes standard with the same size tires we put on the dually. This is the most frustrating situation. http://www.dieselplace.com/forum/smileys/smiley7.gif


What does everyone think? Both my fiance and I are mechanical engineers, and we have built cars and dune buggies, so we know a lot about vehicle performance. However, this is the first diesel we have ever owned. Does any of this sound normal to anyone?Edited by: EllieMae71

I have a 2500HD DMAX that has about 36,000 miles on it. I have seen many people who have the same truck as your towing to the desert from San Diego all the time - towing big trailers.


One thing that I do know about the truck, it takes a while for that motor to break in. Mine developed more power and better mileage the longer I had it. Once it was up to 10,000 miles, it improved a ton. Towing a 4000# boat I am getting 14mpg, unloaded I am getting about 18-20.


I have not heard of people having problems with the clutch fan.


As far as it shifting into 4th gear or any gear - it will do so in order to maintain speed; however mine barely shifts at all once I am up to speed. Make sure you are selecting the "tow/haul" mode when you are pulling your trailer.


I have heard of people burning more oil during break in (first 10,000). Leaking oil from the intercooler is not normail IMO.


With the tire size change being so minor, I would not think that it is causing the problems that you are having.


My recommendation to you is to start keeping a log and timeline of the problems, actions taken, and results - just in case, ya' know? You may also want to try a different dealer. If all else fails, call the GM Customer Support line and start a case with them.

Thanks for the advice. We have kept a log, and we have tried to contact GM customer support and they won't call us back. We have been calling them for weeks and leaving messages and no one will respond. We are at 10,000mi. now. So we have been fighting with GM for the last 8,000mi. We have had to cancel trips because we can't tow our trailer. I think we are going to have to get a lawyer pretty soon. The sad part is, the only other dealer in town for Chevy is worse than the one we are going to. Oh, and you would think they would be nicer to us since we have bought 3 $45,000-$50,000 trucks from them over the last 1.5yrs. I just cannot believe the way they are treating us!


Thanks again for your advice!

Have you tried this http://www.gm.com/automotive/parts_for_consumers/service_sup (http://www.gm.com/automotive/parts_for_consumers/service_support/customer_assist.htm) port/customer_assist.htm

Oil leaking from the intercooler sounds serious to me- like oil is leaking from the turbo.

There is definitely something wrong. I heard of some people overheating and low power not to long ago, so do a search and see what you find here.

Thanks for the advice. I went looking and found a ton of information on the overheating issue. There was another link to gm-diesel.com and found many threads dealing with the same issues we have.


I do have great news though. On Friday, my fiance spoke with the regional service manager, and after a long conversation and threatening to go to the lawyers Krohn & Moss, he offered to buy back our truck and admitted they have had to buy back many of these trucks because they do not know how to fix the problem. So they take the buybacks head-to-head with another truck just like it and they said they have no idea why some work and some don't.


So they key words when dealing with these people are Krohn & Moss. The second we mentioned those names, the manager asked what we wanted him to do to make us happy. Unfortunately, we said we wanted to bring the truck back and be given a new one that works, and the scary response was "I can't be positive I can give you one that works, therefore I will not put you in a new 2005 truck." So instead they are buying our truck back.


So now we have a 35' toy hauler and the dune buggy season is starting, and nothing to tow our toys to the desert with. Any suggestions?


I am going to make another post with the VIN # and listing the problems this truck had. I would really hate for the dealer to turn around and sell this truck to some poor soul who doesn't know any better.


Again, thanks for the advice!

That stinks about the truck. I think it will be a while before the majority of the GM techs are fully trained on troubleshooting, being a newer product. I wouldn't give up on the GM or Chevy truck though, by far, the VAST majority of the GM trucks on the road perform great. Unfortunately there are a few that have ongoing problems. I'm sure that if you had maybe just picked a different color or walked up to a different one there would have been no problems with it.


Good luck!