1998 Yukon transfer case troubles

[redwing4900]

My 4wd is activating with no input. I was hearing a clunk when I would make a turn and it is from the transfer case activating the front axle. I have changed the motor on the transfer case already but no change to the symptom, there is no code or service 4wd trouble light either. If I pull the t case fuse will this deactivate the transfer case so I can figure out if this is an electrical problem or A mechanical one? Has anyone had this issue? Thanks

 

[drakon543]

possible issues i would look at is your front actuator is starting to fail possibly shorting somewhere causing it to try to engage all the time. the buttons in the cab are a semi known issue im not sure on the methods of failure besides it just stops working. to your direct question about the fuse. yes if you pull the fuse it will disable all the 4wd systems so make sure its in 2wd and pull the fuse. then start diagnosing possible shorts.

 

[redwing4900]

So it’s been awhile. I pulled the transfer case fuse and Drove it around some and the thing is still engaging. Soooo I guess the transfer case is mechanically binding (At least that’s my guess) and spinning the front drive shaft Only (without engaging) since when I went to remove it the front Spindle was spinning freely but the transfer case end was locked up. I was hoping this would not happen, but it looks like the t-case needs to come out and get rebuilt. I’ll be digging through the archives for some help with that...It’s times like this that I appreciate this forum greatly! Thank you to the moderators and contributors for all of your input.

 

[79jasper]

In other tcases, I've seen the shift forks cause issues. May be a "simple" fix.

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