2004 Silverado 4X4 Diesel

[57ToyBox]

I'm looking at picking up an 2004 Silverado 2500 Ext-cab 4X4 Diesel auto.
Owner claims.
Serviced regularly, with nothing but the best in fluids.
Anything I should watch out for?
Any does or don't?

[northerngmc]

2004 was the changing year for the Duramax. Early 2004's had the LB7 and then mid year they changed to the LLY. Check your vin number. If the 8th digit of your VIN number is a 1, then it is an LB7 Duramax(the early one). If the 8th digit is a 2, then it is an LLY(later 04.5).


The LLY is highing HP and torque, but not much more.

LB7 Power / Torque: 300 bhp (220 kW) @ 3100rpm / 520 lb·ft (705 N·m) @1800 rpm

LLY Power / Torque: 310 bhp (230 kW) @3000rpm / 605 lb·ft (820 N·m) @1600 rpm

My 04 LLY has had some wiring problems. The front left and right rear wiring harness to the injectors is a little too short and can cause problems. GM has a different harness.

Also watch were the wiring comes over the alternator. It is wrap tied into position and the wires can rub through and short. If it hasn't been done cut the wrap tie and put a piece of rubber hose under and then reattach.

Also mine had the Service Brake light come on. Found out the ground wire is a problem. Ground wire in located on the bottom of the cab, basically below were your left foot sits when driving. I just needed to clean it up, retighten and I painted mine.

www.dieselplace.com is a great forum for questions.

Do be scared by what I have written. Each truck series has there problems. Some say the LLY's had a cooling issue problems but I have not had any.

My 04 has 110 000 kms on it and I still really like it.

I get about 21 mpg, summer time highway driving without a trailer at 120 km/h. I have a 30 ft holiday trailer I pull with it and on a trip from Edmonton to Vancouver I averaged 16 mpg.

[57ToyBox]

Great information Blaine. Thanks a bunch. I'll watch out for that 8th digit and keep what you said in mind.
I'm off to check out Diesel Place .com
I'll B back

[hatchaddict]

the LB7 has injector issues but gm extended the warrenty to 7yrs 200k but just on certain circumstances with the injectors. the LLY does have cooling issues its a head gasket problem but is only on 05 and 06. and the wiring problem on the LLy is for #2 and #7 injector plugs factory used straight plugs and pulled them to plug in but from them having tension all the time its loosens the terminals and breaks contact when this happens you loose 4 cyl. gm revised the plug to a 90* plug and a bracket to hold the wire from pulling its a whole update kit