To check transmition fluid level park on level , turn off engine, pull out dipstick and level should be between the two marks. Same procedure with or without backhoe. Although if you di just change fluild or just put hoe or loader back on, it would be good to operate controls full range to make sure no air in lines. I would not check level while engine running like on a car as manufacturer does not recomend checking with the engine on in manual.