Cougar 2 Spur/Pinion mystery

[McMike]

I'm back again after, I think, solving my diff problem.
I have now received some new spur gears from Schumacher (89,92,95) and a 19 and 22 pinion from HPI. Imagine my surprise when I fitted the 89 spur with the 19 pinion only to find there was no way I could get them to meet! Tried the 92, again, same problem. I only managed to get the 95/22 combo to meet.
What's going on there then? There is no way I can move the motor (Brushed LRP V10 Spec 5) closer to it as it hits the gearbox. Have brushed motors enlarged in size or something in the years I've been away? It's not a case of the Cougar not designed to take those spur or pinion sizes as they are listed in the gear ratio charge and are sold as spares.
I'm very confused...