Transmission problem code 022 and 024 anyone help

My discovery V8 petrol auto has a transmission problem, when u drive it pulls off in first and then changes to 4th at this time the s and m and D light start flashing, I get the local auto trans shop to read the problems and 2 fault codes came up 022 stall speed monitoring and 024 voltage supply check.
The car drive s like this most of the time but today it worked as it should for 1 hour so im thinking its more electrical connection maybe? Can anyone help with this as the shop said to me that they need to open the box to see what the problem is? Thanks