What fluid do I put in my differential?

There are two types of differential fluid. One is mineral oil, which is a natural, crude oil-based fluid. The other is synthetic differential fluid, which is created in a lab. As with all synthetic oils, synthetic differential fluid oils can be fine-tuned for optimal performance.

What is the best differential fluid?

Editor’s Choice: Red Line 75W90 GL-5 Gear Oil. Red Line Synthetic Oil is one of the top companies making synthetic lubricants for all parts of your car.
Lucas Synthetic Racing Gear Oil.
Royal Purple Max-GEAR.
Liqui Moly Fully Synthetic Gear Oil.
Mobil 1 Synthetic Gear Lube LS.

What kind of oil do you put in a rear differential?

The construction and maintenance of front differentials mirror that of the rear on the same vehicle. Most differentials call for SAE 75w90 gear oil, however some heavy-duty and limited-slip differentials need SAE 75w140 gear oil. Consult your owner’s manual for the proper weight oil to use.

What happens if I put 10W40 instead of 5w30?

If you use 10-w-40 instead of 5-w-30 specified by the manufacturer then the viscosity of 10-w-40 used by you will be higher and oil thicker than what is specified during winters. Similarly the oil viscosity will be higher and oil thicker than specified during summers.

What if I use 0W 20 instead of 5w30?

The 0W or 5W refers to the pumpability in cold temperatures. Therefore, a 0W would flow more easily than a 5W and could be an acceptable substitute. Thus, it is suitable to use a SAE 0W-20 as a replacement for SAE 5W-20 application. **Offers same protection as 5W but also provides faster flow and better fuel economy.

What happens if you dont use friction modifier?

The friction modifier increases the friction between the clutch plates. If you run a gear oil that has no friction modifier in it the diff will act more like an open differential. In short it will decrease the function of the lsd. It won’t cause any damage.

Do you need limited slip additive?

Yes, you need the friction modifier even if the oil you are using says it’s for Limited Slip diffs.