I have SSM IV drives. While changing the lube this season, noticed something that has my brain wondering.

The drive reservoirs do not have a vent. There is a threaded fill plug in the inner transom plate. Whenever you loosen the drain plugs, there is always pressure built up in the drive, to the point it wants to squirt out when you loosen the plug.

I was thinking of adding a remote oil reservoir bottle, that has a vented cap, or vent in the bottle. I had a problem with a leaky propshaft seal, and even after replacing the seal, I still had a little leak.

Even when I remove the fill plugs on the inner transom plate after a run to top them off, there is PSI built up, and i can hear it release when i loosen the plug.

Looking towards the back of the boat on the left side of the transom assembly i think there is a vent cap. At lest the set of factory inner plates I have have one. I will take a pic tonight. It has a wobble cap like car rear end.

Yes, I noticed that there is a pipe plug there, no vent style fitting! Looking at the merc diagram, couldnt find anything for a vent there on the SSM, so thought of ordering the one for the TRS, hoping its the same thread size.

Thanks man, That is exactly what i was looking for. I figured there has to be a vent!

i will take a pic tonight. who knows if mine are factory but both are the same for the set I have.

I just looked online, and the part they show for the SSM fitting, is the same part number for the velvet drive vent. Sooo, looks like i need to order a couple. No need to take pics, but thanks for offering!

I will bet that has to be why my prop seal was weeping on one of the drives. Prob to much pressure and the seals couldnt take it.

Pic:

Looks like someone rigged a little extension tube with a vent, prob to stop puking any drive oil. I ordered the Vents last night, should have them by friday. I think i will rig it just like yours, with the little extension tubes. Good idea. Thanks for the pics bud....