it’s the rear.There’s a small bracket between the cups on the u -joint,it’s like a small 1/4” wide bar that each end slides into the joint.Well when I was using my pry bar to separate the universal joint ii broke just one end of the part( not sure what u call it,but the parts store sells them)so I used a flat screw driver and sorta put it back in place.Whle I was under there I unhooked the decoder and plugged back,and there are 2 ground wire on the drivers side on the frame that were rusted.So I cleaned them and drove it last night with messages and NO TC light came on. Will keep updated.
SERVICE 4WD message
- Thread starter Pepper
- Start date
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blackbeard_lives
TYF Newbie
- Joined
- Oct 30, 2023
- Posts
- 18
- Reaction score
- 6
ive got the service 4wd light on my new to me 02 gmc 1500HD, gotta rebuild the 4l80e first, no reverse and fixing the servo pin didn't fix it must be a bad reverse band, was gonna look into the 4wd light after i get the trans working again but noticed this post and am glad to see one fix found, will try to find my fix another day.
It will help your diagnosis to get the 4wd code(s) that triggered the service light.
