Mods on intakes, dual exaust and trans cooler


Asked by Chrisb Mar 25, 2010 at 12:59 PM about the 2003 GMC Sierra 1500HD 4 Dr SLE Crew Cab SB HD

Question type: Car Customization

This is a good truck with plenty of power.  I know I can’t get much better that 14MPG, but I need some advice on mods.  I’d like to add a good intake for more air, dual exhaust and is the trans cooler within the radiator?  I want to know if it would benefit to add an after-market Trans and oil cooler or is the stock system sufficient.  I’d like you to give me part numbers for the intake and exhaust if you can.  I appreciate any input.    

Macon Ga.

2 Answers


I have the exact same truck. Bought it in 04 and have been gradually adding mods since. I have a airaid cai, bbk throttle body, custom dual exhaust, and a hypertech power programmer 3. I can honestly say that each of these mods had minimal affect on the trucks performance.


I also do a LOT of towing and have never had a problem with overheating, including the trany. The only time i have had an issue is when driving long distance at highway speed with a plow. I have been tossing around the idea of a e-fan to maybe solve this problem, and to get a little more low end hp and torque.

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