I was on my way to work tonight and had to slow down faster then just breaking could help on a down hill grade so I locked the converter and let the trans brake help. I've done this before, no issues. well this time it stayed in a lower gear and kept the RPMs at close to 3,000. normally you can give it fuel and it will upshift and your fine, but today it wouldn't upshift. I had to pull over and put it in park and then I pulled back out on the road and everything was fine. build on trans was around 50k+- ago, is there a problem or a warning with this happening? or am I just paranoid?