How does the speedometer gear stay in? MY bud took this apart and I cannot find a clip

that oil seal is a bugger, plenty of dripping speedo cables out there. retainer ring is for oil seal. There is no room for a clip on the shown model. Its a drop in with a retention mechanism of a stop in the trans to prevent it from walking out. Its a 1 bolt 'harvest': pull bolt, pull housing out and avoid the fluid draining, pull and pocket the gear, move on....