95 Jimmy wow's

I'll start out by saying that there is a multitude of information within this forum. :biggrin:
OK here it the dilemma , I have picked up an 95 Jimmy for my daughter, it's got 1442650
miles on it, one owner and in great shape. The engine runs just a good as my 97, no problems
whatsoever. However, it did need some minor things done to it.
I'm puzzled with 2 things on it... first thing done was a trans service since it appeared to over due. There was not metallic or bits of clutch pack materials in the pan, just a slight bit of the normal gray stuff on the magnet . Now this trans has a slight whine when put into gear, weather it was reverse or drive and when driving ti would change pitch with gear shifting. It doesn't hesitate or slip in any gear, the oil isn't burnt. "And your answer ?"

Second strange thing but maybe related to the trans, I don't know... after I tuned it and did everything I reset the computer, and took it for a drive. No problems but the SES light came on.
The next day when I took it for a spin the light was off ?? I reset the computer again and haven't
had a chance to see what codes may get pulled. "Any suggestions?"

Thanks in advance for any and all input.