Help! Weird electrical and transfer case issues

[LilJashy]

So, I just bought a 07 H3 two days ago. The oil light was on so I got an oil change. Now the oil light is coming on only at idle or low rpm.
Also, a diagnostic from the mechanic shows a transfer case circuit malfunction.
And also, the transmission fluid was apparently extremely low.

So, a lot of problems that weren't happening on the test drives. Any advice?

 

[Happy Hummer]

Welcome,
All of these items have been thoroughly covered multiple times.

 

[alrock]

For the transfer case, have you tried cycling it into the different modes to see if they work? What prompted the test for a malfunction? For the oil, I'd start by simply making sure your oil was filled properly after the oil change. The issue could be the oil pressure sensor right above the oil filter. Is there a check engine light on?