2000 4x4 service light

[dwaynehand]

Please help,
Have a 2000 with a 246 transfercase. 135,000 mi
I was driving, noticed the 2hi light wasnt on, i switched to auto, went in fine. then the service 4wd light came on. I switched it of and the message stayed. I resodered the switch and nothing changed but the 2 hi light worked. I took it to a mechanic with a tech 2 and he pluged it in and it started working fine. It switches through all modes now, but if I put it in 4hi or low, after a mile or two the light come back on, but i can switch it off and restart the truck get it back into 2hi, in 2hi I have no probs, no light. I was wondering, does the front drive shaft spin in 2hi, i marked the shaft and backed it up, it moved. I was thinking the clutch pack? also in 4wd when u turn sharp it feel super tight, like something is going to break. does the front diff dissengage the cv's and the tranfercase lets go of the front drive shaft, also when I go from 4 to 2, i get a big clunck.

[j cAT]

Originally Posted by dwaynehand

Please help,
Have a 2000 with a 246 transfercase. 135,000 mi
I was driving, noticed the 2hi light wasnt on, i switched to auto, went in fine. then the service 4wd light came on. I switched it of and the message stayed. I resodered the switch and nothing changed but the 2 hi light worked. I took it to a mechanic with a tech 2 and he pluged it in and it started working fine. It switches through all modes now, but if I put it in 4hi or low, after a mile or two the light come back on, but i can switch it off and restart the truck get it back into 2hi, in 2hi I have no probs, no light. I was wondering, does the front drive shaft spin in 2hi, i marked the shaft and backed it up, it moved. I was thinking the clutch pack? also in 4wd when u turn sharp it feel super tight, like something is going to break. does the front diff dissengage the cv's and the tranfercase lets go of the front drive shaft, also when I go from 4 to 2, i get a big clunck.

re-soldering the switch is a common fix....
the transfercase fluid[trac II] I replace every 30,ooomi...the drive train has gm specific DTC'S...It would be good to get the code...then report here what it is...

when you put into 4wd the front wheels lock,,and the rear wheels are engaged with the front...

IN 2wd the front axles are freely rotating...independently..

IN auto 4wd the front aXles are locked together BUT are not engaged with the rear wheels,,,tranfercase,,,,...when slip is detected then automaticaly they are connected to the transsfercase...

the encoder motor may be binding or drawing too much/too little current and this is why the light comes on...replacing the fluid may reduce Binding of the encoder engagement and stop the 4wd service lt from coming on,,,,or possibly the encoder is bad...NEED DTC TO BE SURE...

Remember do not operate on solid pavement in 4wd ...turning the steering wheel hard left/right when in 4wd will damage the drivetrain...only test out 4wd for a short time on solid pavement and don't turn the steering wheel too much..

all tires should be evenly worn....tires with different wear will also stess out the drivetrain..