loading a scraper in 3rd gear?

Personally I never do it, over the years I have worked with people who do, or at least try the shotgun method, load the first part in 3rd then lug it til it grabs 2nd. We are running 6 637g 2. They have less than 2000 hrs on them, two of them are having trans probs. they wont shift back into 2nd, they will downshift from 8th to 3rd then lug til they die, or hit 3rd then jump into 6th. Could the continuous 3rd gear lugging while trying to load be causing a prob?

loading a scraper in 3rd gear?