Carrier gearbox problem - any advice?

[Tom Millward]

Hello all. I’ve developed a problem with my Carrier gearbox and I’m hoping it’s something that someone here has seen and fixed before...

It was changing gear without any problems at all. But I have developed a problem whereby I can no longer get it into 1st or second gear using the gear lever.

If I manually pull the lever on top of the shifter plate across to align with the 1st and 2nd gear gates it moves freely in the neutral gate, but when moving it over to align with 1st and 2nd gears, it initiatially resists and then clunks over into position. From here it will engage 1st and 2nd without any issues. But as soon as it shifts over to 3rd, it will not go back into 1st or 2nd without manually pulling the selector lever over again.

I've taken the shifter plate off the top of the gearbox and all looks ok inside the gearbox. There’s nothing obviously amiss.

Does anyone have any thoughts, as I am baffled at the moment?