Allan A. Allan I work of GM for 25+ years. They have finally gotten there issues fixed with the Duramax and allison transmissions. We have no failures with STOCK running trucks. We have had failures with modified diesels with broken and bent rods and damaged piston ring lands. GM have gotten wise to the after market tuner along with Dodge and Ford. If they find out you modified the performance of the truck, they can and in 1 case cancel the warrantty on it. Unless you have 2 PCM's for the truck you can't install and remove the calibration numbers with a tuner. The PCM stores 10 calibrations. The other thing is running biodiesel in the truck. We have found that no more that a 50/50 is safe for the injection pump. Biofuel does not have the same power output the #2 diesel does from the pump. You can install and exhaust system if you want but GM has an after burner tube on the back of the truck. Changing
oil is the most important thing. The new diesels have a tank with this new fluid that help reduce emmissions. The tank to fill cost about $70.00 and will last for about 1-2000 miles of normal driving. The big 3 are all going to do this within the next year. I like the screw on trans filters for the Allison tranny's. Easy to change and just add fluid to top off. Even with heavy duty hauling, the new fluids are holding up to about 75,000 miles before changing. Rearend fluids I would change at 50K if hard towing or high speed driving. Transfercase gets the same at 50K miles. Injection pumps, injectors, and glowplugs have all been improved and have very little failures unless major abuse is found. I know the air in air out story of the motor, stay with the stock filter, it does a better job of keeping crap out of the motor than K&N. See will be surprised at how fast this 2.5 ton truck is when driving. Put a large trail on the backend and it rides like a caddie, smooth and soft. I am sure that Dodge and ford have about the same to offer but GM's is quieter too. That has been tested in truck and car mags. Get some back issues of trailer mags and they have done the testing every year. SHOP hard for the best price. Rick L. PS fully loaded K3500 diesel just went for $58,000.00 OUCH. I paided 26,000 for my truck in 2000. with a sbc.