Trans fail safe prog fault

Hi there I’m new to to site so thanks for having me and listening to me problems, I have a trans fail safe prog fault coming up on my dash normally after about 10 to 15 mins of the car running and when doing more than 60 mph on a bit of a hill. I took it to a 4x4 garage in Sunderland and they said it probably is the gearbox on its way out. It’s a L322, 2006 tdv6 3.0 diesel with 120,000 on the clock, it already had a recon box at 76,000 which makes me believe that it is not the gearbox, the garage took a sample of the oil and said they could not see any debate inside only that the oil was a bit discoloured so they changed the oil and filter in the gearbox but fault is still there it comes on for a few seconds then goes and then might not come back on for the rest of that journey, can anybody out there help.
Thanks

Welcome. Try posting your issue in the Range Rover section . At 46, 000 miles since recon, don't be so sure there's not a problem with the box but for more definitive help Range Rover sectiin is the place

Ok mate many thanks.

You're welcome

Welcome to the forum

RR section over ere:

https://www.landyzone.co.uk/forum/range-rover.10