My Explorer is still a smooth running vehicle, no clanging or knocks at any time while it is running, no oil burning etc. However, have experienced something while climbing a grade, car will downshift and if it continues to decelerate you begin to hear a low frequency sound (call it bogging down?) and then what seems to be the pressure plate or torque converter slipping then engaging? Repeats this about every 1/4 sec. A little difficult to explain. The rpms don't fluctuate per the gauge but seems concerning. Had a trans guy test ride and he thinks its something to do with the engine and it getting power-wasn't confident with that opinion. Aside from this issue, as smooth as it was 10yrs ago. Opinions on how confident I can be in road tripping?