Hi i have a few Rover Colts and 2 of them are starting to pop out of gear. So today i undid the chain, 4 bolts and then removed the pulley and put it on the bench. Take c clip off the shaft and remove cogg. Leave the opposit end c clip on till you split the box. 6 bolts 2 are down low in recess don't miss them. As soon as you split the box u will see why it is starting to pop out of gear. The grease is solid and not anywhere where it is needed. There is a big circular gear (see pictures ) in the middle of that gear you will see two raised blocks and the drive face instead of being nice and square is rounded off on the drive side. The drive piece slips over this rounded off block and then catches again causing the machine to jerk or pop in and out of gear.

If your box is ok i would make time and service it now. Fingers crossed the machine shop can square the faces again.

Before its too late. [Linked Image]
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