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Front/Rear Differential Fluid Replacement
While I replaced the transfer case fluid on my 2003 Toyota 4Runner, I decided to replace the front and rear differential fluid at the same time. The differential fluid lubricates the internal gears, which help transfer power from the driveshaft to the axle. If I want my car to continue running smoothly, I needed to get this maintenance item done. I followed an excellent write-up posted by snowbizx on T4R.org here, which includes both the process for replacing the transfer case fluid and front and rear differential fluids.
Parts Needed for Front and Rear Differential Fluid Replacement
The original specifications for the 4th Gen 4Runner calls for the following: SAE 75W-90, Hypoid Gear Oil API GL-5. I went with the commonly used and readily available, Mobil 1 Synthetic Gear Lubricant LS 75W-90.
This fluid quart pump makes the job easy since you have to move the fluid from the bottle up into the differential fill hole. You can purchase this through Amazon through the link below:
Plews 55001 Lubrimatic Fluid Quart Pump, Fits Standard Quart Bottles
These bottles can be bought through the link below:
Mobil 1 104361 75W-90 Synthetic Gear Lube – 1 Quart
Ignore the part number above, the Toyota dealership parts department put all of my plug gaskets into one bag. I usually recommend getting your parts at the local dealership unless you can find a good deal online that doesn’t try to gouge you on shipping costs. Part numbers for what you might need are listed the link to the forum thread at the top of this page.
Remember to remove the fill plug first before removing the drain plug. First, it helps with air flow in draining the fluid. More importantly, you want to make sure that you don’t drain the fluid, then find out you can’t remove the fill plug, and then get stuck with a differential with no fluid.
Refilling the front differential fluid…
A great link to all of the required gaskets, part numbers, proper torques, and much more information is at top4runners.com. There is a lot of really useful information for both 4th gen and 3rd gen 4Runners here.