Differential fluid, also called gear oil, is the fluid that is poured into the rear differential housing. It needs to lubricate the clutches, gears, and bearings in the rear end.

Luckily, our gear oil already had the additive mixed in. So how do you know when the rear diff is full without a dipstick like the engine oil, the trani fluid, power steering, or even the brake fluid.

A scheduled change of the differential fluid is likely only called for in rear-, four- or all-wheel-drive vehicles, and it may only apply to the rear differential.

The transfer case is a critical part of four-wheel-drive and all-wheel-drive vehicles. How often does its fluid need to be ...

In a rear-wheel-drive car, the differential has its own housing and lubrication, a thick, dark oil usually heavier than 80 weight. 🔨 You love DIY projects. So do we.

Honda Technical Service Bulletin #04-040, dated August 2008, identifies a potential "noise or judder" from the rear differential when turning due to clutch debris contamination in the fluid. This ...

Q: I own a 2011 Toyota RAV4 V-6 all-wheel-drive with 59,000 miles. I have pulled a boat and trailer for approximately 2,500 miles since the car was new. At my last oil change the dealer recommended… ...

Q: The owner’s manual of my 2004 Honda Pilot recommends regular changing of the “VTM-4” rear differential fluid, which costs more than $100 each time.

For those looking to improve cooling for their pickup truck's rear axle and provide more strength, better performance and/or ease of use with a new differential cover, there are a variety of ...

Think your rear differential is due for some re-lubrication? Larry Kosilla is here to show you how to replace your rear differential fluid on this Wrenched. Watch all of our Autoblog Wrenched videos ...