Thanks for the information.
The hydraulic pump for the blade is the same pump that operates the differential steering motor. The hydraulic oil is the supply for this fluid and not the transmission oil. This pump is loud but, if it has become more than normal, check for suction leaks and for the becoming foamy.
Are you seeing transmission temperature too high or hydraulic oil temperature too high?
Is the engine temperature too high as well?
Does it overheat in first speed too?
What type of work are you doing?
Best practices for keeping the transmission cool recommend traveling in reverse equal distances to the pushing forward to allow for cool down time of the oil. If you are constantly pushing forward and not allow for cool down time, the transmission will run hot.
Have you checked the sender or gauge?
When you say turning will stall the engine, is this at low idle or high idle?
Do the blade functions stall the engine?