Any P1870 Code??
Just talked to a trani guy about almost same issue. Mine does it all the time but only after driving for 20 minutes. So trani is hot.
The Trani Guy says there is a " I forget the name' in the Valve Bodyof the 4L60 trani that is made of soft metal and wears out at 100K miles-ish. They bore it, put in a sleeve to bring it back into spec. and that should solve the issue.
This '99 Blazer is my daughters.
It's the Newest car we own. I'm used to seeing Valve covers , not Wire looms everywhere.
Other vehicles in the stable:
1975 Jeep CJ5 Bought in 1980 Chevy powered fiberglass body I did the work
1985 Chevy Stepside Pickup// Original owner 298K miles
1989 Volvo 244 //Original owner 305K miles
1991 Ford Explorer Bought for $450 w/182K miles it now has 336K miles on it.