A little update from our looking into the cooling issue and the shifter detent issue:
On the cooling, the thermostat opens at 165 degrees. Combine a low opening thermostat temp, a big radiator, and a fairly large bypass hose and if you aren't working the tractor much the coolant remains about 165 degrees. The needle does not move off the cold peg until 50 C, or about 122 F. The OEM says this is as designed and all is well. The cooling system is desgined for a tractor that is using a good portion of it's 50 HP on a hot day, and will keep the unit cool. Running cool under a light load is going to be as designed for this unit. I suppose if the tractor always sees light work, one could ask Mahindra if a hotter thermostat would be appropriate, but honestly I'd just leave it alone.
On the detent issue, we have sold a bunch of these 5010's and we have seen this once, and it was almost the exact same scenario. It is with a customer with 2.5 miles of private gravel roads that he grades regularly. It is in the hills, and he too has a 10% plus grade and with the tires filled and a heavy float on the back, if he is in high range 1st gear under compression going down hill, with the float in the air, the shifter will walk itself into neutral. We replaced his detent ball and srping and that fixed it. 5 minute job. Phil, I'll order you one and you can see if this works for you as well.