Chuck, when you say "too thick" what exactly do you mean? Do you believe that Amsoil 75w 110 is too thick for a summer car?

 

I'm still surprised that Honda used an odd size 23mm for the fill plug.

 

I am reminded and think this as well every time I service it.

 

No, I don't think any 75W-110 GL5 is too thick. I'm not sure about 75W-140 though as I don't know the temperature the differential runs. I doubt it runs at 100°C like the engine. The ISO-VG grade of the current LE-1605 is 220 which is smack in the middle of the old SAE 90 range. But it's no longer technically GL-5.

SAE split the 90 grade gear oil specification after our cars went out of production and made the upper half of the 90 grade the new 110 which didn't exist before a few years ago. This means 110 grade meets the "old 90" grade spec albeit in the other half of that old range. 140 and 250, the only higher viscosity grades, remain the same.

New 90 + New 110 = Old 90.

I have two quarts of Amsoil 75W-110, and two of LE-9920 75W-140. Game time decision which gets to play in the differential this year. Both claim to be GL-5 hypoid gear oil.

-- Chuck

 

Agree. It's such an asinine choice; I normally like purchasing tools but buying a wrench for one bolt (likely ever) was annoying. Would love to know why it was chosen.

 

Remember you can just put the same magnetic drain plug (on the bottom) in the upper fill hole for the Diff. use the same wrench, easy breezy. Been recommended previously.
Been using amsoil 75w110 for years and I tow a 500lb tire trailer about 1200 miles/year- every year I change the diff fluid and there is virtually no "paste".

darcy

 

Oh? Well I do have a spare diff, Maybe I will rob the bolt.

 

I know some folks just replace the fill plug with a drain plug to make them both 24. If you do this, which crush washer should you use? I ask this because I had the experience recently of using the wrong crush washer for the drain plug and the darn thing leaked a bit. Had to pull it and replace the crush washer with the correct crush washer. Leak went away instantly. Not a big deal probably on the fill plug. But, little leaks are a PIA and can cause real problems.

 

avoid dealerships, plain and simple.

 

Use the crush washer that goes with the plug. I always wondered why they used a copper washer on the fill plug and aluminum on the drain plug, chances are you could use either on the fill side without issue.