Checking rear diff fluid - hot or cold?

[4OYOTER]

I changed my rear diff fluid a few months ago. Out of curiosity tonight I double checked the level after a 30 mile or so drive. As soon as I got the plug off I was surprised to have a steady overflow rolling out. I decided to let the excess spew from the fill hole for a few minutes. I'm guessing it was probably a 1/4 quart or less that came out.

Should the rear diff level be checked while cold or hot? Now I'm second guessing myself if I should check it while cold again and top off. I haven't done any water crossings so I know there was no chance of water contamination.

 

[renau001]

Factory service manual doesn't specify hot or cold, but it does say to re-check level after driving. I don't know how much the temperature of diff fluid changes from cold to hot, but I suspect since it's a relatively small amount of fluid there's not a ton of volume change. It only has to be within 5 mm of the fill hole. So as long as you checked it with the vehicle level, I would probably leave it alone. I checked my levels cold at 15k, and it showed they were basically filled to the min level (5mm from fill plug) from the factory. I did not top off.

 

[wfo9]

LOL. will make no difference. Don't worry about it.

The differentials are very forgiving to the amount and type of gear oil. Just don't let it get contaminated and keep it close to the fill hole and you are good.

 

[SATSTRAIL]

LOL. will make no difference. Don't worry about it.

The differentials are very forgiving to the amount and type of gear oil. Just don't let it get contaminated and keep it close to the fill hole and you are good.

Bingo! Agreed.