downshifting when towing up a grade

[paulbrgr9999]

My c20 (350, turbohydramatic,410 rear end) is doing great towing my toyhauler (approx 5000lbs loaded) until I come upon a grade to climb. Then things are slowing way down. Petal to the metal and 45mph. The trans will down shift but then upshift almost immediately when a little more speed is attained.

So would it be best for me to just use the shifter and put the trans in a lower gear and climb the grade and then upshift at the top of the grade? Is this a stupid question? Like of course you should down shift manually you idiot!

Also, at what rpm would the 350 be making maximum torque? Shouldn't I keep the engine at that rpm?

I would appreciate your opinions and ideas. I dont have much experience towing except a couple of jet skiis. The toy hauler is much more of a challenge for me and the c20.

paul