Changing oil in final drive unit.

[mixongw]

The fill hole is pretty obvious but where's the drain hole?

[Nessism]

Drain hole is on the bottom.

[duaneage]

Should have a magnet built in, clean the fuzz off it.

Don't overfill it, that can cause big problems.

[emjay]

... Don't overfill it, that can cause big problems.

Yeah, just fill it up to the point just before it overflows.

[bwringer]

If you're talking about the secondary gear housing on the engine (850+ shafties), then here ya go:



Remove all three plugs to drain, replace the drain plug at the bottom, then fill slowly just until gear oil starts to come out the level plug. More is not better here. Replace the level plug and the fill plug.

If you're talking about the final drive back at the rear wheel, then it's the big obvious drain plug on the bottom. Fill just until gear oil reaches the bottom of the fill plug threads. Again, more is not better -- gear oil expands significantly in use.

The manual calls for 90W gear oil which is difficult to find. Any GL-5 gear oil in the same range will work fine (75W-90, 80W-90, 85W-90, etc.) As long as it's marked "hypoid" somewhere and is about the same thickness it'll work.

[duaneage]

Yeah, just fill it up to the point just before it overflows.

I add the recommended amount from the manual using a measuring cup.

[BassCliff]

HI Mr. mixongw,

For your perusal:

Secondary Gear Oil Change

Note: I had the gear oil too high in the original procedure but made note of the correct level in the addendum.

Final Drive Unit Oil Change

The crush washers for the drain and fill plugs are mentioned in the addendum of the secondary gear oil guide.


Thank you for your indulgence,

BassCliff

[Steve]

HI Mr. mixongw,

For your perusal: ...

I suppose you found that on "some guy's website"?

.

[fb9]

Make sure not to strip out the drain threads like I did. Lefty-Loosey. Good luck!

[BassCliff]

I suppose you found that on "some guy's website"?

.

Indeed.

Just Google "bikecliff" and see what's on top.

I wish that guy would learn how to use menus on his webpage.


Thank you for your indulgence,

BassCliff

[Steve]

Yeah, I Googled it.

Saw that web site right there at the top, but then there were several videos of you jumping your bike over a cliff, too.

Video 1

Video 2

Video 3

the list goes on ... :

.

[radbrad]

I can't get the fill hole loose on my bike. What do you think would happen if one never replaces the final drive oil?

[BassCliff]

I can't get the fill hole loose on my bike. What do you think would happen if one never replaces the final drive oil?

You'll DIE!


Use your favorite bolt loosener (WD-40, PB Blaster, Deep Creep?), get a BIG, LONG box end wrench (or socket), then lefty loosey. That means pull the wrench toward the back of the bike to loosen it. Maybe you can fit a piece of pipe over the wrench to give you more leverage.




Thank you for your indulgence,

BassCliff

[mixongw]

I now feel a little stupid asking that question about the drain plug. I could have dreamed that it wasn't there, I guess. I went out to the bike and there it was in plain site. I appreciate the information on the secondary too.

[mixongw]

Make sure not to strip out the drain threads like I did. Lefty-Loosey. Good luck!

I seem to always have a little confusion on threaded parts that point down instead of up, like the fill hole. The first time I put the wrench on the plug, I had to think about it.

Quote from Twin Peaks: "Look, it's trying to think!"

It's probably just old age.