changing rear gear case oil

[cookiedough]

Going to change out my rear gear case oil with probably Amsoil 80w-90 (or 75w-90) this fall (long overdue), and I know it should take only about 5.1 ounces until full, but will say 6 ounces overfilled hurt anything?  Never done it before and I think other postings have said that if you leave the bottom drain plug in and leave the fill plug out and hold the cycle straight upright off the sidestand, the oil in there should be right at the lower part of the casing without oozing out.  Would 6 ounces, about 1 ounce over, run out of the top hole casing if the bike is straight upright?  Also, would running it first for 15-20 miles or more warm the oil up inside to help the old oil flow out better/quicker like I usually do with car oil changes? 

[NITRO]

Overfilling will cause the oil to spill out of the vent on top of the final drive case. This will make a mess of your rear wheel, but I doubt it will hurt anything otherwise.

I change the oil every 10K miles since I have everything else apart as well. I remove the final drive from the swingarm and dump out as much oil as possible. If you don't want to do this, your plan sounds fine.

[MP]

Not sure how to read your question, but the top hole is a VENT ONLY.  Do NOT remove it!

Remove both side and bottom plugs.  Drain as much as possible.  Replace bottom plug.  Do NOT overtighten.  Fill the side hole, until it runs out with the bike level.  Fill thru the side hole.

If you over fill a little, and put the plug in right away, it will be a little fuller, and OK.

MP

[cookiedough]

that was what I was thinking if overfilling by say 1 ounce at most wouldn't hurt much if any.   With my luck, I will spill a little if measured out 5.1 ounce and then be short an ounce or so.  I'd rather be overfilled by 1 ounce than 1 ounce not enough.   I'm guessing standing bike straight upright over 6 ounces would ooze out the side filler hole?  I meant side filler hole, not top vent like you stated MP.

I'm a little surprised only 5.1 ounces is all we need in such a large bike.  If I remember correctly, even my ATV's rear diff. fluid (same stuff) take over 10 ounces when I last changed them both a few years back.

[MP]

Remember too, if you drain it OFF the bike, ie tipped over, it takes MORE oil, as a little stays in the bottom if on the bike.  If you refill ON the bike, just fill to hole.

MP

[NITRO]

And as an aside, I've never measured out the oil, I just fill until it's near overflowing. Should be a pretty easy job for you.

[jrhorton]

As others have stated, just fill until it begins to ooze from the fill hole.  If the bike is held upright it is impossible to overfill.  If you leave the bike on the sidestand, then you could add too much.

Make sure to clean the magnetic recess on the drain plug.  I've found that a few Q-tips along with carb cleaner spray (or gun scrubber if you have that) will help get the gunk out of the magnet recess.

Don't over-think this job....it's about as easy to do as anything could be.  I change mine every other motor oil change and use the full synthetic Mobil 1 75W90...

Good luck

[mello dude]

Thanks for bringing this up for a reminder.  I hadnt thought about changing the gear oil. My bike still has the factory oil in it. It's due. ---  Still its approaching 19k on the clock. (Blame MBS)

[cookiedough]

thanks guys.  I'm also long overdue probably never been done in 10 years and still factory gear oil as well at 21K.
You know me, I probably overthink everything and would screw it up.  For example, an easy oil change on the wife's SUV this weekend turned out luckily caught in time.  1st oil change on new vehicle from the factory they overtightened the drain plug/aluminum crush washer so hard it took both hands on the socket to pry it off.  Me being an idiot, I did not replace the aluminum crush washer since looked o.k., but a tad more flattened out due to factory overtighten.  I put oil drain plug and original crush washer back in and tightened up fairly tight.  Apparently, not tight enough since had a softball sized puddle yesterday morning on garage floor that the misses saw while backing out for work.  Found out due to the crush washer being a tad more flattened out due to factory overtighten of drain plug, I had to crank as hard as I could by hand the drain plug back on (1/4" turn more at most) just like it was from factory to get the oil from seeping out the drain plug hole.  I lost about 4-5 ounces of oil in 1 day of sitting and could've been worse if we didn't catch it say until 1 week later.  Never had that happen before in over 200+ oil changes I have done in my lifetime. Story of my life:  what can go wrong probably will.  

[JetDriver]

 Never had that happen before in over 200+ oil changes I have done in my lifetime. Story of my life:  what can go wrong probably will.  

Cookiedough - You have to lighten up on yourself, man.  200+ successful oil changes, and the one that leaks is "The story of your life!"  DUDE!!!     

[MP]

 Never had that happen before in over 200+ oil changes I have done in my lifetime. Story of my life:  what can go wrong probably will.  

Cookiedough - You have to lighten up on yourself, man.  200+ successful oil changes, and the one that leaks is "The story of your life!"  DUDE!!!     

LOL!   

MP

[cookiedough]

good one, I had a bad day at work when I wrote it.  Matter of fact, everyday is a bad day at work.  Need to win the lotto and quit for life! 

[Parker]

Go Go Powerball!

[cookiedough]

Go Go Powerball!

Man do I agree, need to win the powerball!!     One of the bosses was an A-hole again last night and his extra curricular drinking outside of work is starting to show up at work.  Two of his best, most competent, hardest working warehouse employees have left in the past week and I suspect more to come.  If he thinks it is bad now with him bitching all the time, wait until he has no one left worth keeping around.  Oh well, time to get ready to go to work yet again and see what is in store tonight, cannot wait, NOT!  Hey, at least I have been driving the Valk to work since it has been so nice and sunny out although 47 degrees at 11:30 at night coming home is a tad chilly.

[cookiedough]

Remember too, if you drain it OFF the bike, ie tipped over, it takes MORE oil, as a little stays in the bottom if on the bike.  If you refill ON the bike, just fill to hole.

MP

Got er done today finally.  All went well except the tubing was a pain to snake around up top of the exhaust even with the hard sidebags off since only about 1" between hole and exhaust pipes.  Had the misses hold the bike upright to see if any extra oil would flow out and it did a tad maybe 1/2-1 ounce.  Bottle said 26 ounces left of a 32 ounce bottle so close enough, just a tad overfilled is o.k.

She commented while sitting on it how easy it was to hold upright and level with such a low center of gravity she even could ride it? Being only 5'5", maybe I guess?? but not flat footed on ground unless I got my big ___ on the back - ha ha!!

Boy, the old oil about 5 ounces was sure a chocolate milk color and the drain plug had 1/4" of gunk/grease built up on the bottom of the plug that I wipped clean.

I wanted to get as much 11 year old OEM gearcase oil out as possible so I sat on the bike and tipped the bike to the right as far as humanly possible while sitting on the bike and my wife said probably almost another ounce dripped out.  I pumped a tad of the new Amsoil gearcase oil in with the bottom drain plug off and I was surprised it came out looking like new expecting old gearcase oil to darken the new oil up some.  Good to go for another 20K but hopefully not another 11 years, more like 5 years tops.