Terrano WD21 Gearbox issue

[marmel]

I've got a 93 Facelift WD21 Terrano.

Most of the time it runs fine, gearbox changes smoothly etc.

Occasionally when I take off from an intersection the gearbox will refuse to change up, it just sits in 1st.

The only way to get it to change is to quickly turn engine off and then on again and it works perfectly. I don't think it's the torque converter, garage that did the last WOF didn't seem to think that would be the problem.

Now when I purchased the vehicle it had a screw holding the hold/auto/Sport switch in the auto position. Not sure why that was done, could be the last owner kept bumping the switch as it just sits right next to hand brake. Still had the same issue with the screw there so I took it out.

It almost seems to be an electrical problem, gearbox thinks I want it to hold in gear.

Any thoughts on this?