Hey guys. Just bought my first duramax yesterday. A 2006 2500 LBZ with only 40000 miles. Ive had a few generations of the cummins diesel but I wanted to try one of these. The owner before me installed a 5 inch MBRP exhaust but since the downpipe looks factory I am assuming that it is a cat back system. Thats the only modification he did besides the 6 inch lift kit. I have two questions. The first is what would be the best intake/programmer/exhaust combo for my truck and the second is that it seems to shift kind of hard. harder than my cummins did. Is this normal for a Allison transmission or should I be concerned? Thanks in advance all you vets out there.

 

Unless you want to push big HP number your intake and exhaust should be fine for quite a bit more HP then stock. The Allison should shift smooth. It may be from a number of reasons, change the fuel filter first. Then the external transmission filter. If it is still shifting hard after a few hundred miles with the new filters then it is possible that it was abused and will need service. what size tires are on it? Did the programming get changed for this?

 

It doesn't have a programmer on it yet. ill be getting one soon, probably a diablo since that is what I am familiar with and have run on my cummins. the intake is still stock so that will be replaced with a aem brute force, again what i am familiar with. it has 35x13.5xr18 on it right now that will be switched to 35x13.5xr20 when i get time since I hate chrome wheels on a black truck. thanks for the information about the tranny. with as great of shape as the truck is in and how clean the interior is i dont think it was abused but who knows. ill get on changing the fuel and tranny filters.

 

What I mean by abused is driven hard and with the 35s the transmission will start slipping and having issues. Is the speedometer correct of off? Changing the tire size and in putting the new size into the program will help the transmission shift at the correct points which can smoother things out. If not then the odometer will be off too which means it likely has higher miles then it shows. It my not be much but it is something.

 

Ive heard that 10% is a good number to add to the odometer reading with larger tires. so i should have about 4000 more miles if the speedometer hasnt been changed. i havent had a chance to check the speedometer against my gps speedometer but i will after the holiday. a programmer is first on my list to add to the truck. thanks for all the tranny man. help

 

Get efi live with some guages, best tuning out for the duramax.

 

honestly the stock intake is the way to go unless you start making big numbers like 500+ Gm did there homework on the stock intake! And yes efi live is the only way to go on a duramax thats what im saving up for. Good luck