Hello very intermittent gearbox fault randomly does a funny change an locks in 3rd gear till engine switched on and off seems to be more when vehicle warmed up... these are codes im getting put some images up cheers...
Assuming it's a 6HP26, then I'd take a sample of oil and check with a good torch for metallic particles. The two DTC's you've shared indicate shorted solenoids, likely from an over-abundance of metallic particles in the oil... If that's the case, then rebuild or replace.
Does it suggest a slipping clutch pack? A correlation issue between speed sensors or a duff speed sensor
But would there be a ratio issue through all the gears....
I am not so sure on your gearbox but there is usually a multi pin round plug that connects to the gearbox underneath the car. The o'ring inside can leak. If it has leaked it can cause signal issues. Normally these are changed along with the filter and oil. There are certain models also with a couple of other seals on the valve block.
Have you had the gearbox serviced at all at any point?
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