S40 V40: 1996 1.8 S40 gear knob/stick questions

[theravenousbeast]

Haven't had a need to post here for a while thankfully but here goes.

I had the gear lever break off randomly on a drive home. Actually it kinda went all mushy and after I reversed the car into my garage and tried to get the car back to neutral was went it completely broke off. Anyway, managed to find the whole gear selector unit and replaced it but the unit doesn't have the top bit where the rubber knob from the old car would fit. I've tried pulling that off the old stick but it does not budge at all. Is there a trick to this?

Do I have to have that bit? Or can I find another sort of universal knob? It's the lift reverse to the top left corner one. I don't necessarily care if its some generic aftermarket thing, I don't plan on carrying on with the car for more than 1/2 years. I did go to a couple of shops to check on some knobs but all of them blocked off the reverse spring even when not fully pushed into the stick.

Second question, though is more of what I'm interested in. I haven't had many cars but if I had to guess the lever breaking off like it did couldn't have just been old age. What could've caused it? There is some play in the stick when in gears but could the worn linkage bushings caused something like this?

Would appreciate any help