New to forum from missouri

gmctruckguy87 · October 20, 2015

hey guys im new to this Ive had my 6.0 about a year its 2008 gmc sierra 2500hd SLT 4x4 with the 6.0 I was wondering about the cold knock everyone talks about . im also curious to anything I should do about high mileage I have 182,000 miles as of tonight would appreciate any help or tips on what to do also I know the mileage sucks when I bought what about the custom tunes is that worth it . thanks in advance

txab · October 20, 2015

Welcome

Tattooo · October 20, 2015

Welcome to the forum

sahls01gmc · October 20, 2015

Welcome! I have 100,000 more miles on mine, and I trust this thing anywhere. The cold knock has never gotten worse, in fact I don't even pay attention to it anymore.

Custom tune "might" be worth it, I've just grown used to the mileage. It's no Prius......it was meant to haul!

Tattooo · October 20, 2015

Wow....almost 300k

Formulabruce · October 20, 2015

Hi, the Knock is not involved in an '08 truck usually as the short, silicon sided pistons somewhat changed after '03 I believe.

If you run stock 245 tires, you can jump to 265. If you can find one, its worth it to get a mileage XS super tuner. THis will fix your speedo for a tire size change and you can get your 4L80E to shift up at lower speeds, which helps with economy. Of course a more "road" type tire will help alot as well. Keeping the rpm at or under 2500 is key to economy with our "box in the wind" vehicles good luck

gmctruckguy87 · October 20, 2015

Thanks everyone and thanks for all the tips ... Supposedly my truck is the z74 off road package and I swear it sits up so high it looks like it has a leveling kit but I do have 265/70/17 Toyo all terrains that I love ... Is there anything special you guys do for the high mileage and has anyone had troubles with the custom tunes is there any chance of blowing a tranny or blowing the motor up pretty much this truck is my daily driver so anything you guys tell me I'll apprecuste

00Silverado4x4 · October 20, 2015

Welcome! I have 100,000 more miles on mine, and I trust this thing anywhere. The cold knock has never gotten worse, in fact I don't even pay attention to it anymore.

Custom tune "might" be worth it, I've just grown used to the mileage. It's no Prius......it was meant to haul!

I also have the "cold knock", so I treat it as, start truck, once knock is gone I know it was "warmed up" enough to start driving....lol

Formulabruce · October 21, 2015

High miles, do a full trans service, and re use the stock pan gasket.

gmctruckguy87 · October 21, 2015

Stock trans gasket on what and do you service front and rear diffs

gmctruckguy87 · October 21, 2015

Also I have like a miss or something sometimes when I'm going slow it's like a lag I just changed plugs and wires a few months ago could it just be high mileage or something else I have to keep this truck for another 4 or 5 years because the dealer I bought it from was shady and screwed me 5 ways to Sunday and of course being a younger guy I havent figured out all there games yet .. But I was just curious if there is something else I need to do and also the diffs were changed at 132,000 miles I have 182 now and is purging your transmission. Going to make it mess up I always heard if you didn't do it regulary that it will break up all the build up and make it slip