Went to check my trans fluid after driving 30 miles. Found it about 2-3 quarts too high on dipstick. I have not serviced trans in over 2 years. I do not have any shifting issues. A Tech at Chevy told me the seal in between the transfer case and tranny may be allowing fluid to pass thru. Any suggestions what to do next?

 

Pop loose a cooler line and attach a hose. then get a friend and drain some fluid (start truck and let it run for 10 seconds at a time,while checking). Once its down to the full mark attach cooler line,drive it for a few minutes and check level.

For the tcase remove the fill nut,fluid should be at the bottom of the hole. if its super empty or LOTS of fluid gushes out when you remove it,sounds like the seals gone. If its low,top it off and check the fluid level after driving it for a while.