I've just had a 14 speed gearbox of a 4 series Scania repaired. It was going to have 1st gear rebuilt & there was a broken ring/collar gear (for synchro). I was hoping it would fix the problem I have of when in high range (the top 3 gears), when trying to change down into "1st" (7th/8th gear), it's locked out for a long time, before it will go in. I assume forcing it still makes it grind like before. So if I want to change down to 1st, it needs to be revved to go in, like a non-synchro.
Could there be something else, like a external air valve component that needs replacing, for it to operate smoother?
Or likely to still be internal, like a heat-damaged shaft causing it to be clunky?
-I haven't timed how long it's locked out of gear, but if it's 10 seconds or so, I'd have to ride the clutch for a long time.