Weird 4 Wheel Drive Problem

[SS1LE02]

I have a 2000 half ton 4.8 truck with the push button transfer case selector. I noticed recently that it wasn't working in 4 hi/lo, however it does work in 4 auto. I have no SES light or "service 4 wheel drive" message either. I had an extra push button switch that I swapped in for the old one. No difference. I just replaced the 4 wheel drive actuator on the transfer case. Is there anything special to installing that. It was just a black plastic long round thingamajig with an electrical connector that just screwed in. No change after installing it. I switched out the push button selector with no change yet again. With the truck off I can hear the actuator working when I press the buttons. With the truck running, switching it into 4 lo I can hear the clunk, but it doesn't work.

 

Anybody have any ideas.

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Bump this for my first post.

 

My truck started doing this yesterday. 2HI is now neutral and Neutral is now 2HI. 4HI and 4Auto is a ok, 4LO is a no go. There is no MIL's and nothing displayed on the DIC.

 

The encoder motor and sensor were replaced about 20,000 miles ago. Time for another?

[Chanks7]

I dont know the answer but I would like to know also. My 03 started doing the same thing as yours SS1. I can hear transfer case motor shifting and I can even get into low range but still only rears spin. 4 hi is completely inop and when I use auto it seems like sometimes it will help a little bit like the left front is engaging but i will still fishtail all over. Now hear is the weird part, i put vehicle on a hoist and 4 hi mode all 4 wheels spin, but i put vehicle on snow pack in 4 hi and can spin the rear wheels easily while i hold the brake pedal. I checked codes no codes and no warning messages. One little clue i have is that I was driving along in 4hi and i heard a pop followed by a noise like when you put a playing card in your bike spokes. I pulled over and checked for a flat tire and since then it hasnt worked. Also it seems like sometimes when making sharp right turns I can hear a clicking sound from the right front. Any ideas???

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I spent the $60 to have the dealer check it out, its too damn cold to crawl under it here . As expected the encoder is bad again. I can understand 1 failing (at 17,000 miles) but 2!? My 01 Suburban (180,000 miles) has never failed and I think its the same part.

 

Dealer want over $600 for the motor and encoder assembly. I did not ask how much just the encoder is. Advance sells a reman for $275. Anyone have any other reliable sources?

[Chanks7]

Found my problem, the clutch pack in the transfer case is worn out. Fluid level was low and fluid entirely black and stinks bad. Looks like I will be replacing the clutch or a reman t-case....