It is electric 4wd. When I try to engage in 4HI it does nothing, going slow or dead stop in N. 4Low works when I am in N you hear the clunk. Any Ideas on why the HI wont work???

 

i dont think its supposed to CLUNK my t-case makes a small clicking noise. thats about it.

 

It maybe a vaccum problem, with your 4wd I would check all your vaccum lines going to your transfer case!!

 

4LO will typically thump/clunk in due to the gear ratio change. That sounds normal.

What do the dash lights do when you are attempting to engage 4HI? If you have Auto4wd, try running through the OBD2 Non-Automatic Transfer Case Diagnostics and let us know what the outcome is.

The other thing to check/try is to check/clean the electrical connections at the switch (in dash), TCCM (transfer case control module - behind the passenger side kick panel), and at the encoder motor (on the transfer case). We have had some members that had similar problems and it was a loose connection at the switch. Others have had corrosion issues at the connector on the TCCM.

Hope this helps!