I recently changed transfer case oil in my 07 with 87k on it and afterwards just for fun tried 4wd in the yard. Wouldn't engage high but if I out it in neutral it would go into 4 low. When it was in low the 4lo light was on but the other 4wd wasn't illuminated . (can't recall what lights were on before). I rarely use 4wd so not saying related to transfer case oil change.