Uphill Shifting Question

[jcperform]

I also lock out the OD in hilly areas with my 06 screw 5.4 towing a 7 x 7 x 18
5000 lb toyhauler to prevent constant shifting and keep temps down. It seems to me most of the time it would downshift from 3 locked to 2 locked,....if I leave the OD engaged it will shift in and out of lockup and the trans temp goes up as does the oil temp,...BTW my flat towing temps with deep trans pan, synthetic oils, 25% antifreeze with Water Wetter, 3:55 gears, 29.4" tires are as follows:
trans(flat loaded) 150- 165 hills 192 max
CHT 200 218
EOT 204 238 max uphill 110 ambient
Coolant 205 224 max

I have 600 lb tongue weight, friction antisway, rear axle sway bar,...very stable

This is all with Bill's custom tow tune,...

cheers !