Final Drive Oil Question

[BikerNewsman]

I want to replace the old final drive oil with fresh. The owner's manual says to use a straight SAE 80 HYPOID gear oil. All I can find within a 20 mile radius that seems anywhere near compatible is "standard", full-synthetic, and synthetic-blend gear oil in 80w90. One place has an 80w90 "Hypoy" gear oil, but has the notation on the bottle that it is for Limited Slip differentials.

My question is... what is a safe substitute for what the owner's manual calls for, and/or does anyone know of a source for exactly what the manual says to use?

The bike is a 1985 GL1200 LTD with CFI.

[Burnout]

The most common gear oil replacement will be 75w/90 full synthetic. Most stores will stock this weight. I use Amsoil marine 75w/90 that I get at NAPA. If you have a supply problem in the automotive market, also try a farm or heavy truck outlet. Good luck finding something in your area.

[SIR tricky]

I have been using standard 80/90 gear oil since 1985.

[BikerNewsman]

Thank you both for your replies. I guess my main concern is that nothing I've found mentions being for "Hypoid" gear use since the Hypoid gears have a different configuration and a higher stress factor than other gears. Perhaps most of the gear oils in that SAE range are now manufactured to account for those factors????

[Burnout]

The full synthetic and blends will have you covered for the "hypoid". Read the bottles carefully for anything else. Todays oils are way better than back in 1985. Even regular gear oil will be ok. The most important part is to be sure to change it reguarly. I change / flush mine every fall just before I put it away before winter.

[wingandaprayer]

I use 75/90 synthetic gear oil -I use a marine gear oil "squeeze bottle" with the pointy top I had around to fill the drive case, with the bike on the center stand, while lying on my special garage floor flattened cardboard box.

[bs175dths]

I use 75/90 synthetic gear oil -I use a marine gear oil "squeeze bottle" with the pointy top I had around to fill the drive case, with the bike on the center stand, while lying on my special garage floor flattened cardboard box.

My gear oil sat for two years so I decided to 'flush' out as much as I could. First I drained the old oil, I could have cut it with a knife, then added a small amont of oil to the gears. I hand rotated the rear wheel (don't forget neutral - or at least take out the spark plugs :lol: ) to help thin out the thick, old oil, then I drained it again. I repeated this process untill I could see clean gears.
Added the required amount and buttoned her up.

BTW - I too have that special garage floor flattened carboard box 'tool'. how weird! =

-Ride On

[BikerNewsman]

Thank you all for your input. I have decided to use the Lucas "M8 Pure Synthetic Marine Gear Oil" (pictured). It exceeds GL5 and is applicable for API SAE Grade 80w90 (among others). It also has "anti-foaming" agents.

Wow! That box thing must be catching on... I use the same thing, only outside. Lol I have a feeling the final drive oil in my bike will be thick also since it too has sat for over 2 years. Plan on giving it a good flush.

[wingandaprayer]

So this post reminded me to change the rear drive oil while Goldie was on the stand for the recent tire change. I rushed out to my garage to check the records OH DEAR I went 3000km over the recommended change interval whatever it was...
I grabbed the special cardboard, a drain pan and a wrench, removed the plug with much trepidation... and watched 500ml of new-appearing synthetic gear lube drain - you could hardly tell the difference to the new oil...
'couse I have been known to forget to write down when I did the last change... :d
Oh well records are back on track now...

[Burnout]

" Special " cardboard for final drive oil ? Do you have a shop farkel that we need to know about ? :lol:

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[bs175dths]

" Special " cardboard for final drive oil ? Do you have a shop farkel that we need to know about ? :lol:

Sent from my PC36100 using Tapatalk 2

because 'blankie' was getting all kinds of rude comments from the other children in the shop......

[85GL1200I]

Be careful when tightening that cap with the o ring when you re-install - had mine off a few weeks ago and it cracked when I put it back on, had to track down a new oil cap

and "no" I didn't do a gorilla tight on it, the darn thing just cracked, honest :oops:

[wingandaprayer]

" Special " cardboard for final drive oil ? Do you have a shop farkel that we need to know about ? :lol:

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Yuuuup!