Few Q's after buying a used 2500HD
 

Hi guys hope I'm in the right section here. Bought a used 06 2500hd 6.0l xcsb SLE 4x4 from auction a month or so ago for an RV puller. It was a highway truck for a sales rep from the sounds of it so mostly an easy life I suspect, visually it's great. The vehicle inspection reported all ok except weeping oil cooler lines at the fittings and replaced a LR axle seal. 130,000km (81,000miles)

I have put a few thousand clicks on it now seems ok, except for a faint whine at about 45-55 mph and more noticeable towing, any ideas?

Also looking for some guidance on maintenance should I just drive it and leave it or do I need to go deeper into it like plugs, wires, tranny and diffs oil changes, cataylic converter concerns.

I picked up a Diablo off ebay for 70bucks not here yet, I see from searching that most guys are reporting a custom tunes are better? I was thinking to run the 91 octane tune for towing anyone think issues with that? I was considering a cat delete shop said easy 5-10 hp there with my kind of miles and leave the stock muffler, but then the tuner will be married to the truck (no cat laws / inspected here) and I have to get a o2 delete tune from diablo.

Does it have pushbutton 4x4 or the floorshift? Mine has the floorshift and will sometimes hum/growl between 55-65, especially when towing or going up a hill. I can reach down and feel the shifter vibrating some but don't know what's causing it. I bought the truck with 40K, has 58K now and it hasn't gotten any worse, so I just turn the radio up when it does it.:eyes:

I would change all the fluids, trans filter, just for peace of mind.

Push button, but maybe my transfer case is the source of the howl?
I agree on the fluids just common sence.

My dads 02 2500hd was howling at various speeds. after a fuel pump change (sounds like fuel pump whine) noise was still there. After lifting the truck up on jack stands and putting truck in gear while idling, I found the hanger bearing on the drvs shaft making the noise. Change it and noise went away.

I am not sure that a 4wd has a hanger, but something to look at. his had roughly 75k on it all hwy.

if you wont 30 to 40 more horsepower you can take the mass air flow sensor off and take out the screen thats a big restriction and take off the coolant hose off the throttle body and putthe hoses back together i did on my 2500hd man what a difference it makes. thecoolant hose makes the throttle body force hot air in the intake these are some restrictions you can remove if any body else no's of any more free hp tricks please post free hp is better than buying hp

:sigh:

Leave the screen intact, its not going to net you 40 hp lol! It can actually cause problems by de-screening it. The TB bypass is a nice free mod to do but once again, dont expect to see any huge power gains lol. :D

^Ignore Idiot Above(Charlie6.0).^ Don't remove MAF screen. Stick to the topic.