Slickshift 50 gearbox oil additive

[Alistair F]

The gear change action on my 1958 350 NH is far from smooth and before I remove the gearbox and dismantle same it has been suggested that I try using Slickshift 50 gearbox oil additive to see if this improves things first. Has anyone had any experience of using this and is there any known reason why I shouldn’t try this? Any advice gratefully received!

[Paul Slootheer]

I suggest before you make use of a oil additive, first check if your clutch is freeing properly.