The differential takes sideways rotation from the driveline and converts it into forward rolling rotation, allowing your vehicle to go around a corner smoothly and comfortably. It relies on differential fluid to lubricate its internal components. Diff fluid degrades over time and accumulates contaminants that can reduce its effectiveness.
When low fluid levels, excessive contamination, or plain old fluid cause problems with the differential’s performance, it’s time for a differential fluid change.
In most vehicles, a differential fluid change is a relatively easy maintenance task that doesn’t need special tools. Some models require you to remove the differential cover before you can drain the diff, while others must have old fluid drawn out through the fill plug hole.
With some vehicles, you’ll need to remove the differential cover to drain the fluid or suck out the old fluid through the fill plug hole.
–Anthony Harlin, ASE Certified Master Automobile Technician
Here are some tips and tricks that can make a differential fluid change easier:
Your vehicle’s manufacturer designed the differential to operate best with a specific type of lubricant. Check your owner’s or service manuals to determine the recommended differential fluid and how much of it you must add to the diff. If you don’t have the manuals or cannot find the information, look for a trusted online source.
Like many lubricants, differential fluid thickens over time, especially in cold weather. Thick oil flows slower, which can prolong the process of draining the differential.
Before you drain the differential, drive your vehicle around the block for several minutes to warm the fluid up and make it flow more easily. Do this if you plan to change the differential oil during cold weather or have left your vehicle parked for a while.
Park your vehicle on a level surface to make sure all of the old fluid is drained completely. Mixing old and new fluid will reduce the lubricating effect, which can lead to issues with the differential.
Look for a flat surface and park your vehicle there. Put chock blocks behind the tires to help prevent accidental movement during the differential fluid change. If you have a rear wheel drive (RWD) vehicle, you might have to elevate the rear end to get the fluid to drain. Use jack stands to raise your car or truck into a position that lets its differential drain freely.
Some differentials have both a fill plug and a drain plug while others have just a fill plug. How you change differential fluid will vary depending on whether or not the differential has a drain plug.
If you have a differential with a fill plug and a drain plug, start by removing the fill plug. Next, remove the drain plug and let the old fluid pour into the drain pan waiting below the vehicle.
Differentials with only a fill plug are more difficult to drain. Draw the old lubricant out with a pump. If you want to check for leftover fluid, put the drain pan below the diff before removing the cover plate.
Usually, you can remove the differential’s fill and drain plugs with a ratchet and socket. However, grime and rust can cause a plug to get stuck.
Some fill plugs and drain plugs need a hex bit socket. You can remove these plugs by lightly tapping them with a hammer before tapping the bit or socket all the way in. This approach helps prevent stripping out the plug by accident.
You can apply penetrating oil to the stuck plug and wait a little bit before trying to open it. If the plug remains jammed, use a breaker bar to free it.
You might find metal shavings clinging to the drain plug when you remove it. Metal-to-metal contact between the internal parts can shave pieces of material from the surfaces, and the shavings eventually make their way to the drain plug.
Clean the drain plug of all metal shavings before putting it back. You want to minimize the risk of shavings returning to the differential and potentially damaging one or more internal parts like the gears.
When you remove the drain plug, check for the presence of a crush washer. Crush washers are a type of seal that helps threaded fasteners keep liquid from seeping through the mating surfaces.
If the drain plug comes with a crush washer, replace the broken seal with a new one.
Follow the manufacturer-recommended schedule for differential fluid changes. Alternatively, experts recommend changing the diff fluid every 30,000 to 50,000 or 60,000 miles. Some vehicles might also require a diff change when they reach the 100,000 mile mark.
Differential fluid loses its protective qualities over time and because of contaminants that eventually mix with it. Old and dirty fluid cannot protect the internal components of the differential from friction and metal-on-metal contact.
Low differential fluid levels also harm the diff. Insufficient fluid increases the chance of overheating and damage from metal parts touching each other.
A differential fluid change eliminates old or dirty lubricant and replenishes the oil level, restoring the performance of the drivetrain part.
The differential drain plug is simple in design but critical in function. If the current or stock drain plug loosens up, the differential can leak fluid, causing major issues with the transmission until you fix the problem. Don’t worry. At CarParts.com, you can easily find a differential drain plug that fits in the differential drain hole.
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Order a high-quality differential drain plug from CarParts.com today and seal your vehicle’s differential properly!
Any information provided on this Website is for informational purposes only and is not intended to replace consultation with a professional mechanic. The accuracy and timeliness of the information may change from the time of publication.