GL-4 gear oil

buck91 · Feb 20, 2015

Probably going to drain and fill middle and final drives in my 1980 xs850g this spring. Book calls for 80, 90 or 80w90 gl-4 hypoid gear oil. Used off the shelf conventional last tim and it worked but I'm looking at amsoil for the next one since its such small volumes. Would the synthetic 80w90 vs severe gear 75w90 offer any meaning benefits? I would think high temps and seal compatibility would be top of my list for requirements. Bike may see cool weather use but nothing like cold winter temps or super high miles between drains...

Fwiw the only reason I'm a bit reluctant to go synthetic is how many motor oil leaks popped up when i switched to M1.. AFAIK all drive units have original seals and gaskets and are leak free at this time

qdeezie · Feb 20, 2015

For what it's worth, Severe Gear 75w-90 is GL-5. I think you mean the Manual Transmission & Transaxle Gear Lube 75W-90.

29662 · Feb 20, 2015

Redline MT-90 is GL-4 rated. However if your not doing extended drain or running in very low temperatures I don't see the advantage to running a synthetic at all. If your previous fill of conventional worked fine I would probably just stick with that and save a little money.

buck91 · Feb 20, 2015

amsoil states severe gear 75w90 can be used in gl-4 rated axles.[/url

[url= http://www.amsoil.com/shop/by-product/gear-lube/synthetic-80w-90-gear-lube/?code=AGLQT-EA]amsoil synthetic 80w90 is rated as gl-4 and is slightly cheaper. Might just go that route if anybody can comment on compatibilty with old seals/gaskets.

aquariuscsm · Feb 20, 2015

In gears and transmissions,I believe in sparing no expense (plus the synth manual transmission fluids in my experience shift better and you only change them every year or so). Tranny,Amsoil MTG. Differential,Amsoil AGL or SVG.

aquariuscsm · Feb 20, 2015

Originally Posted By: aquariuscsm
In gears and transmissions,I believe in sparing no expense (plus the synth manual transmission fluids in my experience shift better and you only change them every year or so). Tranny,Amsoil MTG. Differential,Amsoil AGL or SVG.

Ignore my post. I just realized this is the motorcycle forum

Doog · Feb 20, 2015

Originally Posted By: 29662
Redline MT-90 is GL-4 rated. However if your not doing extended drain or running in very low temperatures I don't see the advantage to running a synthetic at all. If your previous fill of conventional worked fine I would probably just stick with that and save a little money.

I would use the MT-90 because of the small volumes in the final drives on motorcycles. I have used it in Harley transmissions and it is an excellent lubricant.

buck91 · Feb 20, 2015

Well, found my owners manual files, here is a screen capture of the gear oil specs; looks like GL-4 isn't the issue but 80w90 hypoid oil is. Looks like Amsoil Severe Gear FTW.

BigCahuna · Feb 21, 2015

Napa sells GL-4 rated hypoid gear oil in the weight your looking for. It's not synthetic but it will do the job.,,

Kamele0N · Feb 23, 2015

Originally Posted By: buck91
Well, found my owners manual files, here is a screen capture of the gear oil specs; looks like GL-4 isn't the issue but 80w90 hypoid oil is. Looks like Amsoil Severe Gear FTW.

Yea but use them wisely!

If gearbox consists of "non ferrous metals" than stay away from GL5 or GL6 spec.

Use only or original GL4 or "modified" GL5 -----> GL4+ , GL4/5, GL5 + MT1.....it has protection of GL5 class....but with different chemistry wich doesnt attack "non ferrous metals" in your gearbox...

http://www.oilspecifications.org/api_gos.php

GL-4 gear oil

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