'02 2500HD 4x4 with a Glitch????

Are you sure neither front wheel was spinning? If you have a locker (G80) option than 3 wheels (2 rear and 1 front) will spin if no locker than only 2 (1 rear and 1 front) will spin. If nothing in the front was spinning than you have a 4x4 problem.

Well, that's a good point. No, actually, I can't confirm that BOTH front wheels were not spinning. We were looking at the left side only, and just assumed that because the left wheel wasn't spinning, that the right one wasn't either. Hmmmm, don't know anything about this G80 thing(?)

Mike

Nope, I was in a wide open field. The light was on telling me [supposedly] that 4wd-lo was engaged.

On my 03 2500hd, if you go into 4wd low, you have to be in park or neutral. You hear a big clunk, it drops into 4wd lo light and voila you are in 4wd low. I have spun all 4 tires on ice before, but i think ice will spin all 4 tires on any vehicle. Where could i find out about the G80 option on my vin?? 10" of snow and ice and you were spining in 4wd low? hmmm my guess is that you have problems with 4wd.

Well, I say 10" of snow, but that's just what the mountain fire station was reporting for the mountain. The actual depth at the specific location was

+/- 10" depending on drifts, etc. Besides that, the tire's tread were packed with snow/ice, so there was virtually no grip at all. I did put the tranny in neutral, then engaged the 4lo. I could hear the 'clunk', and the light on the 4lo switch illuminated steady.

Mike

G80 is an RPO code for a locking rear end option. Look on the RPO code sheet in the glove box. There will be many codes there that will tell you lots about your vehicle. There are many sites (goggle RPO Code) that list all the codes and what they are.

If you get the 4lo light on steady, this tells you at least two things, the transfer case has made it's shift into "that" range, and that the front differential actuator has "achieved" it's shift. On the older trucks with the heated element actuator, there was a separate switch that would indicate that the actuating fork had moved into engagement, on the newer trucks with the electric actuator, the switch is part of the actuator itself.

If you have a tranfer case problem, you will see a range light blinking, and then it will usually revert back to whatever range it was initially, this tells you the encoder motor attempted the shift, couldn't achieve it, and so you are back where you started. If you have a problem with the front diff actuation, you will usually see the light stay in the range you selected, but it will continue to blink, which tells you the t/case achieved it's range selection, but the front diff did not achieve it's lockup.

Ian

not true ... 4Lo will engage while moving. You simply have to keep the speed down... I believe the last time I transferred from 4Hi to 4Lo I was actually near the 6mph mark ...

Burt

02 HD2500 4X4 ECab LT 6.0gasser [supposedly]

Okay,, I just checked my RPO codes, and G80 is listed. So the right-front probably WAS spinning, but we just didn't see it (?)