On this short drive to the worksite, do you use lowrange?
Feeling sluggish is something like a warning.
AT temp light coming on after slowing down can be real, the trans, if it is hot gets less cooling after slowing but still has leftover heat that needs to be dissipated.
Getting hot in the winter is not normal, if it is hot as you question.

Cheers, Charlie
If It ain't broke, Modify it!
87 Montero turbo Converted back in Spring1989
95 Montero SR 3.8 DOHC Only one?
93 Pajero 3 door 6G75 Mivec with paddle shifted 5 speed
Then a Gen2 SR with full coil independent suspension.