I wouldn't dump the 9000 until you find out what's shelled out in this one...
It doesn't make sense to me that someone dumped 30K in the transmission then sell the tractor off a year later. That's 30K they'll never see back. I'd wager that the hammer is about to fall on something else and it's more than the radio.
They were good tractors.... but realistically... at 9500 hours it's had a transmission and brakes. It's probably got hydraulic issues that result from the brake and transmission failures... and the transmission itself may be a result of the brake failure.
It's got front duals.... probably had the snot pulled out of it. Engines were '10000' hour expected life... so it's near. It might go 15000. Might also crack a piston tomorrow.
If it was me I'd pull every drain and mag plug in the tractor and look for metal. I'd get the hydraulics good and hot and see how their performance is... preferably have someone analyse them with pressure/flow meters.
Mabey I'm a cynic... but I can almost guarnantee you there is ~something~ about this tractor that's going to cause you major heartache.
I just know I would not drop 30K on the transmission and sell it a year later. I'd scrap the damn thing on the spot or repair it and hold...