Already changed rear end oil

[Robert]

I was having wrenching withdrawal with the bike so I decided to tinker a bit and changed the rear end oil. Kind of glad I did it was a bit dirty and the bike does feel smoother. Yea I know how much smoother can it get right I remember with my 01 I changed the fluid and was surprised to see a little bit of metal in it. I did not see that here but it was a bit low and shimmered a bit.

[hungryeye]

I'm going to dump mine along with the engine oil and filter at 2000 miles instead of the 4000 set by Honda. The manual also says final drive oil change at 24,000 miles, that's a stretch. I'll change final drive at every engine oil change interval, I thinkin every 6,000 for me.

[AdrianR]

I'm going to dump mine along with the engine oil and filter at 2000 miles instead of the 4000 set by Honda. The manual also says final drive oil change at 24,000 miles, that's a stretch. I'll change final drive at every engine oil change interval, I thinkin every 6,000 for me.

And when  you do BY ALL MEANs replace it with synthetic oil...I went to Meijer and bought a bottle of Lucas Oil synthetic marine gear oil (80/90w)..it was reasonably priced too...

The bottle contains 32oz...and used it with my last bike...Since the differential holds a bit of 4.oz. I will never need to buy it again...

[hungryeye]

I hear ya!

[AdrianR]

I was having wrenching withdrawal with the bike so I decided to tinker a bit and changed the rear end oil. Kind of glad I did it was a bit dirty and the bike does feel smoother. Yea I know how much smoother can it get right I remember with my 01 I changed the fluid and was surprised to see a little bit of metal in it. I did not see that here but it was a bit low and shimmered a bit.

Hey, just did this myself...swapped out the diff oil with Lucas Oil Marine gear oil...full synthetic...just like I experienced with my last bike...it IS smoother!

I simply cannot overstate how much better it is with full synthetic...

[maddoggie501]

I just changed the gear oil at 4000 miles.  It was dirty and there was some black residue in the drain plug magnet area.  I put in the stock 80w honda gear oil and it wasn't fully synthetic.   I'll go hunting for fully synthetic and change it again.

[dans2014]

  Synthetic is the best way to go in any diff. Even my Ford motorhome calls for it from the factory and it holds 12 quarts.

[Robert]

Synthetic is the best way to go in any diff. Even my Ford motorhome calls for it from the factory and it holds 12 quarts.

12 quarts of synthetic rear oil  But the price for a rear change with 12 quarts wow.
Liquimoly makes a rear end moly additive its really good you may want to consider this also. Increase fuel milage

https://www.fcpeuro.com/products/mos2-gear-oil-anti-friction-liqui-moly-lm2019?gclid=COf0p-H3iMcCFYmPHwodlIADQA

[hungryeye]

Your motorhome must be an F650??? 3 gallons,

[dans2014]

It's an F-53 Bounder. I got a case from Summit racing for 9.99 a quart to the door! and yes, it really held 12 quarts. I couldn't believe it!!!

[F6Dave]

I found this info on the HondaF6B forum.  People think the gear oil in new GL1800s is black because Honda adds MOLY, but actually that is not the case.  The black color comes from a phosphate coating Honda applies to the ring and pinion gears during the manufacturing process.  That coating is anti-corrosive and also helps with the lapping process of the new gears.

It's worth mentioning that a lot of F6B owners have found their final drives under-filled by the factory.  Mine was an ounce or two low.  It's worth checking if you have a new 1800.  I'm unaware of any failures resulting from this.

[hungryeye]

I found this info on the HondaF6B forum.  People think the gear oil in new GL1800s is black because Honda adds MOLY, but actually that is not the case.  The black color comes from a phosphate coating Honda applies to the ring and pinion gears during the manufacturing process.  That coating is anti-corrosive and also helps with the lapping process of the new gears.

It's worth mentioning that a lot of F6B owners have found their final drives under-filled by the factory.  Mine was an ounce or two low.  It's worth checking if you have a new 1800.  I'm unaware of any failures resulting from this.

It may be better to leave the factory stuff in the final drive full term, just check level and top off.

[F6Dave]

It may be better to leave the factory stuff in the final drive full term, just check level and top off.

That was the consensus on the board, though I doubt it makes much difference after a few thousand miles.

BTW, I always change my final drive oil when I change the rear tire.  It's easier since the tire is off the bike.  However, I have no doubt that the oil could last far longer.  The 24K interval seems reasonable.

[Robert]

I also found mine slightly under filled thanks for saying something about the B's Dave. 

[maddoggie501]

Well, mine was under filled also.  The owners manual says it holds 4.1 ounces when draining and refilling.  However, it also says to fill to the bottom of the fill hole, just like most cars rear ends and manual transmissions.  i measured what came out and it was about 4 ounces   i put 4 back in, but it was not at the lower level of the fill hole.  it took around 5 to 5 1/2 ounces before it started dripping out. 

[hungryeye]

Is anybody checking it hot, after a 20 mile ride at least, they say to hold upright, if on center stand the unit may be slanted down forward? I will change mine after 6k miles.

[maddoggie501]

You should check it hot and drain it hot.  I put the bike in a front tire locking stand, so the bike was upright.  I filled it until excess oil started dripping out the fill plug.  I waited until the excess oil came out and put the fill plug back in.

[bradrcfii]

The manual says to turn the bike tire to drain the rear end.  I am not able to do this without a center stand.  Is it really necessary to turn the tire.

[maddoggie501]

With the front wheel secured in a front wheel stand, I was able to lift the rear tire by placing a jack under the center stand mounts on the bike.  I turned the rear wheel just to see if any more oil would come out.  I didn't notice any more.  The rear end was hot so it came out like water.

[Robert]

I appreciate the love of the bike and the desire to make sure our girls are perfect but to check and fill rear fluid is not difficult and should take no more than 10 minutes. I drain it hot or cold on the side stand, open the drain plug let it drain into the pan, open the fill plug look in the bottom of the case through the drain hole and see if there is anything in there. Then fill it with oil on the side stand to an approximate level of about 2/8 th of an inch below the fill hole, then stand the bike up with the drain pan still there and the fill hole open.  Wait a few seconds till the overfill comes out or if not fill a bit more repeat and then close it up. 5 oz of oil does not expand that much when hot so its not to worry. This job is a no brainer so don't over think it just enjoy the tinkering on your bike. I have never turned the tire on any rear end I have drained.

As a side note its easy enough to change rear oil at the same time you change oil. I don't do it every time but about every other time even that often is really not necessary. On new bikes I have found bits of metal in the case so I change it more often other than that its not a frequent thing.