What lower unit gear lube?

What lower unit gear lube should I use in my 175hp BlackMax? Is it difficult to change?

Re: What lower unit gear lube?

Merc Gear Lube from your Merc dealer. Pull the bottom screw then the top vent let drain. Check for water and gear shavings as it drains. You will need a pump to refill you can get one at Wal Mart for about 12 dollars. Pump oil in the bottom until it comes out the top vent hole. Put the vent screw in and put the bottom screw in. Replace the washers under both the vent and drain screw every time you change the gear lube. So you will need to pick up some washer when you get your gear lube.

Re: What lower unit gear lube?

dsinger said:

Check for water and gear shavings as it drains.

Click to expand...

I have gear shavings stuck to my magnetic drain plug.

Re: What lower unit gear lube?

How many shavings? It's not unusual to see small 'strands' but if you're getting large chunks on the magnetic drain plug, and flecks of metal are apparent in the drained oil, that's a problem.

If so, the lower unit needs to come apart for diagnosis/repair/replacement.

This past summer I was over at my good Wrenching Buddy Mr. "T"'s place and we drained the oil out of a Merc V6 that had a 'clunky' gearcase.

It was so full of metal that when we put the oil in a glass jar and let it settle out, the layer of ground-up metal at the bottom of the jar was (as I recall) an inch thick or more!

Needless to say, the innards were ground to bits and it was cheaper for "T" to find a good used lower unit than it was to repair it.

Don't panic if you see just a few flecks of material. Some wear is normal and you will get particles on the magnet, that's what it's there for.

If the propshaft spins smoothly, and the lower unit shifts well, I'd just clean off the drain plug, renew the oil, and then check the plug again after running for a few hours (and periodically after that).

Checking it regularly for metal bits will allow you to spot 'impending doom' and get it fixed before there's too much damage.

BTW, Wal-Mart also sells Hi-Vis marine-grade oil, for a bit over $3/qt and that's a pretty good deal compared to outboard shops. I have not observed any diff in quality between that oil and mfr's.

Note some higher-perf and newer gearcases might require a performance-grade of outboard mfr's oil but that'd be specified in the owner's manual. Your average, garden-variety outboard is happy with marine Hi-Vis.

HTH..........ed

Re: What lower unit gear lube?

Usually small amounts of metal in the gear oil are caused by slow shifting, letting the shift dogs bump corners repeatedly. These things need to be shifted smartly to limit the damage. When you shift, it should go clunk, not rattattattattabump.

A 175 horse V6 is hot enough that I would run Merc High performance gear lube in it.

hope it helps
John

Re: What lower unit gear lube?

Agree with suggestions. Buy the highest grade of oil Merc makes is my best bet.....forget the names on the container, but on the reverse side, if you read the info on the two readily available types, yours will use the higher performance type.

Also Pennzoil has a syn that I have used. Forget the verbiage on that container.

The magnet is on the drain plug for a reason. I wish all OEM engine mfgrs would have a magnet in their plug.

They are there for a reason so, as stated, don't be alarmed if you see metal particles......just think, if it twern't for the magnet, they would maybe fall to the bottom of the gearcase, but otherwise circulate in your oil.

A large piece could be a gear tip that you knocked off in shifting. Probably not that big of a deal, but still you need to shift correctly as John pointed out.

My 2c.

Mark