Nut on gearbox

[AMM]

Hi.

I recently changed the flex disc and tightened the slotted nut on the back of the gearbox on my manual 230SL.

Also changed the output shaft bearing seal.

I refilled gearbox with ATF and now have a small leak at this bolt pictured below.

Anyone know what this is and if there is a special way to tighten. I haven't touched this yet. Cannot see it on a parts diagram either.

Thanks in advance

[ja17]

The threaded rod with the slot end is used to secure the reverse gear shaft inside the transmission. The nut locks the threaded rod in place after it is tightened. Since this threaded rod assembly enters the gear box, fluid can escape if the threads are not sealed. You can remove the slotted rod and lock nut completely to reseal the threads. Clean the threaded bore and the threaded rod with solvent and blow dry before using your favorite thread sealer on the threaded bore and the threaded rod itself. Tighten it down by hand until the threaded rod bottoms out good and tight. Lock the threaded rod in place with the lock nut.

[AMM]

Thank you for replying.

Much appreciated.