Hi
A few pictures to tell a story.
On my journey to Germany I already had a worn out Crownwheel & Pinion 48/7 teeth 6.85 final drive which was fitted as standard to my panel van.
I managed to find a 41/7 gear set from a Dudo which I fitted with new bearings and 3 attempts to get the mesh & backlash correct. Id already had practice with the old crownwheel in trying to reduce the noise!
After finishing the job, of course it is necessary to test drive and can report a big difference in reduced in RPM but still the van pulls ok in top.
5 speed 711.113 5th gear 0.806, 6.50 x 16 tyres, 5.857 final drive reduction. weight approx 2300 kg only . High roof option 135mm increase.