Land Rover error message transmission error

Hello I have since a few weeks a recurring error message, gearbox error, with orange lamps, then HDC special programs are not available, suspension is lowered. Comes sporadically high, sometimes immediately with the system test or while driving, can be 2 times a day or not at all. Reading at Land Rover revealed only communication errors, alternator and battery are fit, for the transmission and medium transmission was charged another software, suspicion of the LR master s an oxidized plug connection, have already tested several plugs for oxidation, until now missing, After setting off the ignition and restart everything is gone again, only in the system test the gearbox error is mentioned again briefly but is then again gone. If someone still has an idea what it might be, wanted to change the switch lever with electronics next time and then look at all plug connections at the bottom of the gearbox. Many thanks in advance greeting Mike