Final drive oil change

Ok, I’ve done a motor oil change,
After I was done, I found a full container of synthetic 75w90, it was left over from a previous bike.
Do any of you use this in your final drive? I don’t think I’ve ever used 10 w 40 in a final drive before. I’m aware it recommends 10-40.

Put in what is specified. I have done many final drive oil changes, always used engine oil never had any problems.

Yep, 10/40 is fine bud.

Dont worry about it taking 'a pounding', modern vehicles are designed to use lighter weight oils. As an example, the second series of Isuzu Amigo use 10/40 in the engine, the manual gearbox, & the 4wd transferbox

Jimmyk wrote:

Ok, I’ve done a motor oil change,
After I was done, I found a full container of synthetic 75w90, it was left over from a previous bike.
Do any of you use this in your final drive? I don’t think I’ve ever used 10 w 40 in a final drive before. I’m aware it recommends 10-40.

Use either as you please, I went with the gear oil. Noted that another piece of my machinery used Hydraulic fluid in everything but the engine, the majority of owners of the same unit used the gear oil in place of that in all GEAR applications with no problems.

I wound up using 10 w 40.  And from the looks of things, it really needed to be changed. It looked like about 8 ounces of black water drained out. It was well beyond changing.
Ive been away for work, so im now getting to doing maintainence.
 I dont know why, but i think ill use gear oil next time.
Anyway, the motor & gear oil are changed along with a new air filter. Next projects, coolant & sparkplugs.
 I must say even with the motor and gear oil being beyond changing, she still ran like a champ!!

I always changed my final drive oil whenever I changed my motor oil.  I always had some left over so I would change it.  Did you see my Pictorial that shows that you don't have to remove any tupperware or things?  Just the screw and the bolt?

I just changed my engine oil and rear-drive oil today. A couple of observations:

1) It might be prudent to empty your oil drain pan before draining the rear-drive oil. I didn't, and managed to drop the sealing washer from the drain plug into the dirty oil. I had to set up a strainer while dumping the old oil in order to recover that washer. There is also a sealing washer on the fill plug - it remained in place.

2) Getting the oil in a small hole in a deep recess is kind of tricky. The bolt hole is less than 1/4", so whatever you use has to be smaller than that. I used an irrigation syringe that holds about 2 ounces. I practiced getting the tip into the hole a couple of times, noting the angle and depth the syringe would travel into the recessed cavity. I then used one of my empty oil bottles and cutoff the upper 1/3. I poured about 12 ounces of new oil into the bottom of the cutoff container to serve as my reservoir for drawing oil into the syringe. 12 ounces seemed enough to slightly overfill, and I let the excess run out into the drain pan. I reinstalled the plug and used brake cleaner to flush out any residual oil. Putting the scooter on its side-stand will allow the few remaining drops of cleaner/oil to work their way out.

You can use a box-end or open-end 12mm to remove the drain plug; possibly even a 12mm flex-joint socket would work - but not a regular socket with an extension. The oil will tend to drain back towards the tire, so make sure you catch basin can get real close and even lean up alongside the wheel.

Others have noted that gear oil and engine oil viscosity indications (10w40 vs 75w90) are not on the same scale and you cannot infer the relationship of viscosity between the two type of oils based on their numbers (the gear oil is not twice as viscous as the engine oil). The best advice is always to follow the manufacturer's recommendations. Yes, you can substitute and probably be fine, but you aren't going to improve on what Honda has specified. I know Honda doesn't make oil, antifreeze, or filters; but you can feel confident when they put their name on it, it will meet their specifications.