We have had this unit for quite a few years and suddenly the parking brake locked up. So back in January we sent it in to the dealer for them to diagnose and "fix the parking brake". Among other work that needed to be done to it anyway. We got it back and within an hour of use the brake came on again. At the dealer they replaced, parking brake solenoid, parking brake switch, parking brake pressure switch, and AT323254 which is the vehicle controller. So I am kind of fed up and I dont know what else to do because the machine is basically unusable until this issue is sorted out. Serial number of the tractor is 1T0310JXTBD215911 Things I have done: flushed transmission fluid and changed transmission filter Checked power to parking brake solenoid checked power in and out of parking brake switch checked continuity and power to harness from parking brake switch to solenoid So I am thinking that it might have an internal issue in the transmission. The parking brake will release at 12-1400 rpms, but will come back on again once rpm's drop. Where should I start?
mg2361 started the thread below in Feb 2019 , a solid explanation of a potential cause of Park brake issues. John Deere 310SJ Slow or No Park Brake release at idle
You have a good memory DD ! HeavyEquipmentForums
Welcome to HEF cooperk85 ! You do check your transmission oil level at idle, with warm oil? Definitely check your transmission pressure. Your symptom of park brake application at idle and PB release at higher rpm points to a transmission pressure issue.
Thanks for the reply. I reluctantly decided to send the tractor back to the dealer, we need it back up and operational alot sooner than I am able to get to it. I will keep yall posted with what the brain trust discovers. PS and yes I did check the fluid level at idle. I ran it again this morning and when the tractor is cool the parking break works normally. When it gets warm it instantly starts coming on, or when its cool and I engage 4wd. Thanks!
As the transmission fluid gets hotter, it hunts for ways to get out of doing the work. A system pressure check might be a good place for them to start.