Autobox won't kick into 3rd

[gailus40]

My question/grief for the day - now I've got the gauges in to bypass the buzzer of doom, I have an autobox problem.
Help please - it's been off the road for a month having new oil pump etc, just got her back from the garage at the weekend, and she behaves perfectly normal around town and up steep hills, but on the flat she just doesn't want to go over 35 - keep my foot to the floor, revs creep up to 4-5000, I can hear her screaming, and then eventually drop into the last gear, with revs dropping back to 3000. Will also try seem to slip back, and the revs rise, and I have to stuff my foot to the floor, get the revs up to nearly 5000 to get her to drop into that last gear again. Any clues please, as this is a new one on me. (Wish I'd bought another manual instead). Before I took her from the garage, they tested the transmission fluid at temperature, and the level is fine, and seems pretty fresh fluid. The box has always behaved perfectly till now, and she still does steep hill starts very enthusiastically, just doesn't want to drop into 3rd. Feels like it could be a cable/electrical issue, in that the box just isn't getting the hint to change?
Just looking for advice/explanations to save the garage investigation time as they are fully booked. Someone suggested I speak with ROB - admin? Don't know how to tag him x
Thanks

[gailus40]

I've also recently has new accelerator pedal fitted. Adjustment may be needed?

[Ralf85]

Rob responded to you a few days ago on the same topic on your previous post!

[gailus40]

Sorry - someone else messaged me, and said to try and speak with Rob directly, and to stick up a new thread - not a regular on here, oops

[MGP]

It sounds as if the box is stuck kicked down. Have you checed the adjustment of the throttle cable and kick down cable. It could also be a stuck linkage.