2003 Toyota 4Runner, Projects,

Front and Rear Differential Fluid Replacement: 2003 Toyota 4Runner


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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.

 

4th gen 4runner differential fluid and transfer case fluid 2
First jacked up the car and made sure it was chalked and level.

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.

4th gen 4runner differential fluid and transfer case fluid 11
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

4th gen 4runner differential fluid and transfer case fluid 12
These bottles can be bought through the link below:
Mobil 1 104361 75W-90 Synthetic Gear Lube – 1 Quart

4th gen 4runner differential fluid and transfer case fluid 13
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.

Rear Differential

4th gen 4runner differential fluid and transfer case fluid 8
You see here the rear differential with the fill plug up top and the drain plug at the bottom.

4th gen 4runner differential fluid and transfer case fluid 9
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.

4th gen 4runner differential fluid and transfer case fluid 17
Yucky gunk at the bottom of the drain plug.

4th gen 4runner differential fluid and transfer case fluid 14
Using the pump that goes directly on the quart bottles, it’s pretty easy to pump the fluid up into the rear differential.

4th gen 4runner differential fluid and transfer case fluid 15
After refilling, reinstall and torque the fill plug.

Front Differential

4th gen 4runner differential fluid and transfer case fluid 16
Do the same process for the front differential. Again, fill plug up top and drain plug near the bottom.

Refilling the front differential fluid…

4runner 4th front and rear differential fluid replacement
And now re-tighten everything back up again and we are completely done.

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.

Scott enjoys fixing and improving cars, motorcycles, and his home in his spare time. He does his best to transcribe his journey as he navigates across unknown territory, finds himself in peculiar predicaments, and figures out how things work in the process.

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