[tcr1016]

What weight and oil manufacture do you use for the rear differentials? I need a good oil, but prefer not to use synthetic.

[Sealord]

Isn't gear lube 90 weight? BOL

[heavyhaulerss]

I USE THE JT-7 90/140

[Copperhead]

Most rears and trannys now use a 80w90 synthetic oil. Brand name not so important.

[Kranky]

We use 75W90 synthetic in the Meritor rears, and 50W synthetic in the Eaton Fuller transmissions.

We sample it yearly to keep an eye on it.

Even if the samples test OK, it gets changed every 200,000 miles.