Questions About A 2003 Denali

denali503 · December 12, 2009

hey everyone, i'm new here, just bought a used 2003 GMC Yukon Denali...

Got a few questions for all you veterans with this vehicle, and hoping you can answer some of them, the search function hates me for some reason... =P

1. Does the AWD Denali have limited slip/locking front/rear diffs? there is no G80 option code on my glovebox

2. I think i have the 4l65E transmission, but have gotten others telling me that the 6.0L only came with the 4l80 tranny due to torque/hp limitations, can anyone confirm this?

3. I noticed that the drivers mirror is heated with the rear window heater, but it does not seem that the passenger mirror is heated. Neither mirror have the little defroster icon, so i'm not sure if the pass is not functioning properly or not...

4. Does the seat heater turn on automatically when the truck is started up under certain conditions? if so, way cool. I noticed this last week in oregon with sub 10deg weather, when i started the truck cold, both driver and pass seat heaters were on in the low setting... can't find anything in the manual about it, though. Never did it before we got to the sub freezing temps though so i'm just curious.

Thanks in advance if you all can help me with any of these questions that i have!

smattei14 · December 12, 2009

Mine's and 2006...but I am not sure of all the answers to your questions...but...heres what I know

1. Does the AWD Denali have limited slip/locking front/rear diffs? there is no G80 option code on my glovebox - Not sure

2. I think i have the 4l65E transmission, but have gotten others telling me that the 6.0L only came with the 4l80 tranny due to torque/hp limitations, can anyone confirm this? - Not Sure

3. I noticed that the drivers mirror is heated with the rear window heater, but it does not seem that the passenger mirror is heated. Neither mirror have the little defroster icon, so i'm not sure if the pass is not functioning properly or not... - No they don't...if they don't have the defroster icon...they will not defrost.

4. Does the seat heater turn on automatically when the truck is started up under certain conditions? if so, way cool. I noticed this last week in oregon with sub 10deg weather, when i started the truck cold, both driver and pass seat heaters were on in the low setting... can't find anything in the manual about it, though. Never did it before we got to the sub freezing temps though so i'm just curious.

- nope...that is a problem (good maybe on your end till the summer)....

denali503 · December 20, 2009

thanks or your help...

The seat heaters stopped turning on as soon as the overnight lows got back into the 30's... oddly enough... I did have a viper alarm installed and it's plugged into my obdII connector port so i was curious if the alarm is doing it or if the truck is doing it on it's own. it seems that the alarm is doing it at this point... cool. =)

The mirrors... i have verified. Well on this truck anyways... The drivers mirror gets warm with the rear defroster on, but the passenger mirror is ice cold... no defroster icons on either mirror... oddly enough the drivers mirror is electrochromatic as well and likes to turn headlights behind me green

BTW nice Denali! mine is same color =)

denali503 · December 20, 2009

Ohhh and has anyone figured out how to override the annoying compressor on the back of the truck? =) I don't tow much, and would love to have a regular non-bzzzzzzzzzzz truck when it's started.. =P and i think my rear shocks are on it's last legs and don't want to fork out $500 for new ones =P

dlstewart01 · December 20, 2009

If there is no G80 it will not have a locker. Trucks did not have limited slip, they had locking diffs. with the exception of the quadrasteer. They could be had with a G86 which was a true limited slip. Does yours have quadrasteer. If it does look for G86.

Oh yeah no trucks come with front locking diffs. Would be very hard to steer.

It came with a 4L65 trans.

denali503 · December 20, 2009

sweet, 4l65 it is... good deal... i hear those are decent trannys...

hmm... no G80 in the glove box... guess that means no locker for me.. oh well...

I don't think i have quadrasteer on this denali... although i'm not sure how i can tell... it looks like a normal solid axle . . . no solenoids attached to the rear tires that i can see... although i'm not entirely sure what quadrasteer looks like...

Sorry came from the honda small car family and got a fair deal on this denali so i'm pretty excited, but in the dark about lots of fullsize truck/suv stuff.