Differential Fluid Change DIY Guide (Front & Rear Diff) - for 2025+ 4Runner 6th gen

[Henry]

Great guide posted by @andrewleader at Tacoma4g for the Tacoma, but applies to the 6th 4Runner as well.

Quick Reference

Schedule

• 15,000 miles or 18 months if "driving while towing, using a car-top carrier, or heavy vehicle loading"
  • Otherwise, says to just inspect every 15,000 / 18 months

Front Differential
Approx 1.6 quarts of 75W-85 oil

Bolt	Tool	Torque Specs	Crush Washer Part #
Fill Bolt	10mm hex bit	29 ft‑lbs (348 in‑lbs)	12157‑10010
Drain Bolt	10mm hex bit	48 ft‑lbs (576 in‑lbs)	90430‑24017

Rear Differential
Approx 4.2 quarts of 75W-85 oil

Bolt	Tool	Torque Specs	Crush Washer Part #
Fill Bolt	24mm socket	36 ft‑lbs (432 in‑lbs)	12157‑10010
Drain Bolt	24mm socket	36 ft‑lbs (432 in‑lbs)	12157‑10010

Crush Washer Orientation: Smooth side toward the differential housing; rounded/seamed side toward the bolt head.


Required Parts

• Gear Oil: 75W‑85 full synthetic gear oil, 6 quarts total for front + rear (with 6 qts, I still had extra left over)
  • Preferred product: Amsoil Severe Gear 75W‑85
• Crush Washers:(Toyota part #'s)
  • 3x: 12157‑10010 (2x for rear diff, and 1x for front fill bolt)
  • 1x: 90430‑24017 (front drain bolt)

Required Tools

• Torque wrench that works with the 10mm hex and 24mm socket below
• Socket wrench + extensions
• Breaker wrench that works with the 10mm hex and 24mm socket below
• 10mm hex bit(front diff)
  • These are uncommon, your standard toolset probably doesn't have this
• 24mm socket(rear diff)
  • These are uncommon, your standard toolset probably doesn't have this
• 12mm socket (skid plates)
• Oil drain pan (capacity 6 qt+)
• Rags, gloves, shop towels
• Pump optional — squeeze‑pack oils worked for me
• Tools to lower spare tire (behind rear passenger seat)

Before You Start

• Perform this on level ground.
• Warm the drivetrain with a short drive for easier draining.
• Do not remove a drain bolt until you confirm the fill bolt can be loosened.

FRONT DIFFERENTIAL

Video of front differential change:

1. Remove Skid Plates

• Using a 12mm socket, remove the 8 bolts securing the two skid plates.
  • Support the plates as you remove the final bolts—they can be awkward

2. Loosen Fill Bolt

• Using a 10mm hex bit, break loose the fill bolt first
  • Always loosen the fill bolt before draining... If it’s stuck, you’d be unable to refill the diff
  • Do not fully remove it yet

3. Drain Oil

• Place your oil pan under the differential
• Remove the 10mm hex drain bolt and drain into pan
  • Dark oil with metallic shimmer is normal for diff fluid.
  • Remove the fill bolt to help it drain completely

4. Reinstall Drain Bolt

• Clean the metal sludge off of the magnetic end of the drain bolt
• Replace the old crush washer with #90430‑24017
  • Verify no old washer is stuck on the housing
• Tighten the bolt to 48 ft‑lbs (576 in‑lbs)

5. Fill Oil

• Add 1.4 qt (part-time 4WD) or 1.3 qt (fulltime 4WD) of 75W‑85 oil in fill hole until the oil slightly weeps out
  • It can be difficult to reach the fill plug, but it's possible to use the 1 qt squeeze pouches (I used those and it worked okay) or you can use a pump

6. Reinstall Fill Bolt

• Replace the old crush washer with #12157‑10010
  • Verify no old washer is stuck on the housing
  • Place smooth side toward the differential housing; rounded/seamed side toward the bolt head
• Tighten the bolt to 29 ft‑lbs (348 in‑lbs)

7. Reinstall Skid Plates

• Using a 12mm socket, reinstall the 8 bolts holding on the two skid plates
  • You'll start by installing the rear skid plate first
  • Torque specs are not necessary, snug them well

REAR DIFFERENTIAL

Video of rear differential change:



1. Lower Spare Tire

• Remove the tool kit from behind the rear passenger seat
• Insert and rotate the tool through the rear bumper port to lower the tire fully, then slide it out

2. Loosen Fill Bolt

• Using a 24mmsocket, break loose the fill bolt first
  • The fill bolt is located high on the rear diff cover
  • Loosen it first to ensure that refill won't be a problem
  • Do not fully remove it yet

3. Drain Oil

• Place your drain pan under the differential
• Remove the 24mm drain bolt and drain into pan
  • Expect a larger volume than the front (4+ qts)
  • Remove the fill bolt to help it drain completely

4. Reinstall Drain Bolt

• Clean the metal sludge off of the magnetic end of the drain bolt
• Replace the old crush washer with #12157‑10010
  • Verify no old washer is stuck on the housing
  • Place smooth side toward the differential housing; rounded/seamed side toward the bolt head
• Tighten the bolt to 36 ft‑lbs (432 in‑lbs)

5. Fill Oil

• Add 5.9 qt (except Trailhunter) or 6.9 qt (Trailhunter only) of 75W‑85 oil in fill hole until the oil slightly weeps out
  • Fill through the upper port using squeeze packets or a pump
    • The rear diff is very easy to refill using squeeze packets
  • The correct level is reached when fluid begins to overflow the fill hole

6. Reinstall Fill Bolt

• Replace the old crush washer with #12157‑10010
  • Verify no old washer is stuck on the housing
  • Place smooth side toward the differential housing; rounded/seamed side toward the bolt head
• Tighten the bolt to 36 ft‑lbs (432 in‑lbs)

7. Reinstall Spare Tire

• Slide the tire back under, align the cable, and crank it up until fully seated
  • Verify it is centered and snug

Final Checks

• Wipe down all components and confirm no leaks.
• Dispose of old gear oil properly (O'Reilly Auto / AutoZone / etc accepts it for free)
• Test drive for several minutes, then recheck for seepage.

Notes & Tips

• If a washer seems missing, it's often stuck to the housing. Remove it gently.
• You can do the entire job without lifting the truck, but lifting improves access.
• Slight metallic fuzz on magnets is normal; chunks are not.

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[MikeUtah]

Great guide posted by @andrewleader at Tacoma4g for the Tacoma, but applies to the 6th 4Runner as well.

Quick Reference

Schedule

• 15,000 miles or 18 months if "driving while towing, using a car-top carrier, or heavy vehicle loading"
  • Otherwise, says to just inspect every 15,000 / 18 months

Front Differential
Approx 1.6 quarts of 75W-85 oil

Bolt	Tool	Torque Specs	Crush Washer Part #
Fill Bolt	10mm hex bit	29 ft‑lbs (348 in‑lbs)	12157‑10010
Drain Bolt	10mm hex bit	48 ft‑lbs (576 in‑lbs)	90430‑24017

Rear Differential
Approx 4.2 quarts of 75W-85 oil

Bolt	Tool	Torque Specs	Crush Washer Part #
Fill Bolt	24mm socket	36 ft‑lbs (432 in‑lbs)	12157‑10010
Drain Bolt	24mm socket	36 ft‑lbs (432 in‑lbs)	12157‑10010

Crush Washer Orientation: Smooth side toward the differential housing; rounded/seamed side toward the bolt head.


Required Parts

• Gear Oil: 75W‑85 full synthetic gear oil, 6 quarts total for front + rear (with 6 qts, I still had extra left over)
  • Preferred product: Amsoil Severe Gear 75W‑85
• Crush Washers:(Toyota part #'s)
  • 3x: 12157‑10010 (2x for rear diff, and 1x for front fill bolt)
  • 1x: 90430‑24017 (front drain bolt)

Required Tools

• Torque wrench that works with the 10mm hex and 24mm socket below
• Socket wrench + extensions
• Breaker wrench that works with the 10mm hex and 24mm socket below
• 10mm hex bit(front diff)
  • These are uncommon, your standard toolset probably doesn't have this
• 24mm socket(rear diff)
  • These are uncommon, your standard toolset probably doesn't have this
• 12mm socket (skid plates)
• Oil drain pan (capacity 6 qt+)
• Rags, gloves, shop towels
• Pump optional — squeeze‑pack oils worked for me
• Tools to lower spare tire (behind rear passenger seat)

Before You Start

• Perform this on level ground.
• Warm the drivetrain with a short drive for easier draining.
• Do not remove a drain bolt until you confirm the fill bolt can be loosened.

FRONT DIFFERENTIAL

Video of front differential change:

1. Remove Skid Plates

• Using a 12mm socket, remove the 8 bolts securing the two skid plates.
  • Support the plates as you remove the final bolts—they can be awkward

2. Loosen Fill Bolt

• Using a 10mm hex bit, break loose the fill bolt first
  • Always loosen the fill bolt before draining... If it’s stuck, you’d be unable to refill the diff
  • Do not fully remove it yet

3. Drain Oil

• Place your oil pan under the differential
• Remove the 10mm hex drain bolt and drain into pan
  • Dark oil with metallic shimmer is normal for diff fluid.
  • Remove the fill bolt to help it drain completely

4. Reinstall Drain Bolt

• Clean the metal sludge off of the magnetic end of the drain bolt
• Replace the old crush washer with #90430‑24017
  • Verify no old washer is stuck on the housing
• Tighten the bolt to 48 ft‑lbs (576 in‑lbs)

5. Fill Oil

• Add ~1.6 qt of 75W‑85 oil in fill hole until the oil slightly weeps out
  • It can be difficult to reach the fill plug, but it's possible to use the 1 qt squeeze pouches (I used those and it worked okay) or you can use a pump

6. Reinstall Fill Bolt

• Replace the old crush washer with #12157‑10010
  • Verify no old washer is stuck on the housing
  • Place smooth side toward the differential housing; rounded/seamed side toward the bolt head
• Tighten the bolt to 29 ft‑lbs (348 in‑lbs)

7. Reinstall Skid Plates

• Using a 12mm socket, reinstall the 8 bolts holding on the two skid plates
  • You'll start by installing the rear skid plate first
  • Torque specs are not necessary, snug them well

REAR DIFFERENTIAL

Video of rear differential change:



1. Lower Spare Tire

• Remove the tool kit from behind the rear passenger seat
• Insert and rotate the tool through the rear bumper port to lower the tire fully, then slide it out

2. Loosen Fill Bolt

• Using a 24mmsocket, break loose the fill bolt first
  • The fill bolt is located high on the rear diff cover
  • Loosen it first to ensure that refill won't be a problem
  • Do not fully remove it yet

3. Drain Oil

• Place your drain pan under the differential
• Remove the 24mmdrain bolt and drain into pan
  • Expect a larger volume than the front (4+ qts)
  • Remove the fill bolt to help it drain completely

4. Reinstall Drain Bolt

• Clean the metal sludge off of the magnetic end of the drain bolt
• Replace the old crush washer with #12157‑10010
  • Verify no old washer is stuck on the housing
  • Place smooth side toward the differential housing; rounded/seamed side toward the bolt head
• Tighten the bolt to 36 ft‑lbs (432 in‑lbs)

5. Fill Oil

• Add ~4.2 qt of 75W‑85 oil in fill hole until the oil slightly weeps out
  • Fill through the upper port using squeeze packets or a pump
    • The rear diff is very easy to refill using squeeze packets
  • The correct level is reached when fluid begins to overflow the fill hole

6. Reinstall Fill Bolt

• Replace the old crush washer with #12157‑10010
  • Verify no old washer is stuck on the housing
  • Place smooth side toward the differential housing; rounded/seamed side toward the bolt head
• Tighten the bolt to 36 ft‑lbs (432 in‑lbs)

7. Reinstall Spare Tire

• Slide the tire back under, align the cable, and crank it up until fully seated
  • Verify it is centered and snug

Final Checks

• Wipe down all components and confirm no leaks.
• Dispose of old gear oil properly (O'Reilly Auto / AutoZone / etc accepts it for free)
• Test drive for several minutes, then recheck for seepage.

Notes & Tips

• If a washer seems missing, it's often stuck to the housing. Remove it gently.
• You can do the entire job without lifting the truck, but lifting improves access.
• Slight metallic fuzz on magnets is normal; chunks are not.

Great write-up! However, there are differences between the Tacoma and 2025 4runner.

Different quantities of oil needed for 6th gen 4Runner:
Front Diff w/parttime 4WD – 1.4 qt.
Front Diff w/fulltime 4WD – 1.3 qt.

Rear Diff (except Trailhunter) – 5.9 qt.
Rear Diff Trailhunter – 6.9 qt. (Yes, this is correct!!)

 

[MikeD]

Thanks to both of you. This is incredibly helpful. And seems quite doable for this DIYer.
But can someone guide me on two things:
1. Why (the heck) is there NO change in 150K miles for baseline recommended service but EVERY 15K "if you drive while towing a trailer, using a car-top carrier, or heavy vehicle loading."? I load up periodically and tow occasionally. Seems like such a vast difference in interval (literally never vs about once a year). I'm just confused.
2. What does it mean to "Inspect"? I thought it was literally just to look for evidence of leaks (which I did photographically when completing my "10K Service"), but should I be removing the fill bolt and confirming the oil level (and maybe testing the oil condition)??

 

[Josalbrec6G]

Amazing write-up

 

[Henry]

Great write-up! However, there are differences between the Tacoma and 2025 4runner.

Different quantities of oil needed for 6th gen 4Runner:
Front Diff w/parttime 4WD – 1.4 qt.
Front Diff w/fulltime 4WD – 1.3 qt.

Rear Diff (except Trailhunter) – 5.9 qt.
Rear Diff Trailhunter – 6.9 qt. (Yes, this is correct!!)

Thanks for checking and correcint those oil capacity values! Revised these quantities in the first post.

 

[MikeUtah]

Thanks for checking and correcint those oil capacity values! Revised these quantities in the first post.

When it comes to changing differential fluids, it’s much like changing engine oil. The first thing you need to ask yourself is how long do you intend to keep the vehicle?

If you swap vehicles at 60-70,000 miles, then just follow the Owner’s Manual “Recommended Service” or “Special Operating Conditions” service schedule, depending on your driving habits, and don’t worry about it.

If on the other hand, you intend to keep a vehicle to 200,000+ miles, then it is generally recommended by qualified experts to change fluids more frequently.

With risking entering the “Oil Change Interval Discussion Danger Zone”, this is generally how many 6ths gen 4runner owners plan to address oil/fluid changes:

Oil Change Interval (assuming you are not performing oil analyses)

NOTE: The truth of the matter is no one can tell you how often to change your oil since everyone uses their vehicle differently. Example: Very short trips that do not heat up the engine oil compared to someone who only drives on the highway at 65 mph. Big difference when it comes to when to change engine oil!

General Recommendations:

• Break-in period (0 to 10,000 miles): change oil a few times
• If you go off-road frequently, take very short trips or towing: change oil every 3,000 to 5,000 miles.
• ‘Normal’ driving that does not include many short trips, frequent towing etc.: change oil every ~5,000 miles.
• ‘Exclusively’ highway driving: change oil every 6,000 to 7,500 miles.
• If you want to double, triple check your oil change interval, perform an oil analysis.

Differential Fluid Change Interval

Just like oil change intervals, no one can tell you how often to change your diff fluids. Example: Frequent dusty off-road towing compared to highway driving at 65 mph. Big difference when it comes to when to change diff fluids.

General Recommendations:

• Break-in period: change front/rear diff fluids at 15,000 to 30,000 miles (assuming no unusual operating conditions).
• If you go off-road frequently, heavy towing etc.: change front/rear diff fluids at 10,000 to 15,000 miles.
• ‘Normal’ driving: change front/rear diff fluids at 20,000 to 30,000 miles.
• ‘Exclusively’ highway driving: change front/rear diff fluids at 60,000 miles (Toyota’s Maintenance Schedule recommends the first fluid change at 150,000 miles! Nuts!)

Transfer Case Oil Change Interval

General Recommendations:

• Break-in period: change Transfer Case Oil at 15,000 to 30,000 miles. (My observation: I have always noticed a lot of ‘metal’ in the transfer case oil at the first oil change. I engage my part-time 4x4 about 125 times a year)
• If you go off-road frequently, heavy towing etc.: change Transfer Case Oil at 15,000 to 30,000 miles. (Toyota recommends every 30,000 miles for these conditions).
• ‘Normal’ driving: change Transfer Case Oil at 30,000 – 60,000 miles.
• ‘Exclusively’ highway driving: change Transfer Case Oil at 60,000 miles (Toyota’s Maintenance Schedule recommends the first fluid change at 150,000 miles!)

Just my opinions and two-cents!

LOL

 

[MikeD]

When it comes to changing differential fluids, it’s much like changing engine oil. The first thing you need to ask yourself is how long do you intend to keep the vehicle?

If you swap vehicles at 60-70,000 miles, then just follow the Owner’s Manual “Recommended Service” or “Special Operating Conditions” service schedule, depending on your driving habits, and don’t worry about it.

If on the other hand, you intend to keep a vehicle to 200,000+ miles, then it is generally recommended by qualified experts to change fluids more frequently.

With risking entering the “Oil Change Interval Discussion Danger Zone”, this is generally how many 6ths gen 4runner owners plan to address oil/fluid changes:

Oil Change Interval (assuming you are not performing oil analyses)

NOTE: The truth of the matter is no one can tell you how often to change your oil since everyone uses their vehicle differently. Example: Very short trips that do not heat up the engine oil compared to someone who only drives on the highway at 65 mph. Big difference when it comes to when to change engine oil!

General Recommendations:

• Break-in period (0 to 10,000 miles): change oil a few times
• If you go off-road frequently, take very short trips or towing: change oil every 3,000 to 5,000 miles.
• ‘Normal’ driving that does not include many short trips, frequent towing etc.: change oil every ~5,000 miles.
• ‘Exclusively’ highway driving: change oil every 6,000 to 7,500 miles.
• If you want to double, triple check your oil change interval, perform an oil analysis.

Differential Fluid Change Interval

Just like oil change intervals, no one can tell you how often to change your diff fluids. Example: Frequent dusty off-road towing compared to highway driving at 65 mph. Big difference when it comes to when to change diff fluids.

General Recommendations:

• Break-in period: change front/rear diff fluids at 15,000 to 30,000 miles (assuming no unusual operating conditions).
• If you go off-road frequently, heavy towing etc.: change front/rear diff fluids at 10,000 to 15,000 miles.
• ‘Normal’ driving: change front/rear diff fluids at 20,000 to 30,000 miles.
• ‘Exclusively’ highway driving: change front/rear diff fluids at 60,000 miles (Toyota’s Maintenance Schedule recommends the first fluid change at 150,000 miles! Nuts!)

Transfer Case Oil Change Interval

General Recommendations:

• Break-in period: change Transfer Case Oil at 15,000 to 30,000 miles. (My observation: I have always noticed a lot of ‘metal’ in the transfer case oil at the first oil change. I engage my part-time 4x4 about 125 times a year)
• If you go off-road frequently, heavy towing etc.: change Transfer Case Oil at 15,000 to 30,000 miles. (Toyota recommends every 30,000 miles for these conditions).
• ‘Normal’ driving: change Transfer Case Oil at 30,000 – 60,000 miles.
• ‘Exclusively’ highway driving: change Transfer Case Oil at 60,000 miles (Toyota’s Maintenance Schedule recommends the first fluid change at 150,000 miles!)

Just my opinions and two-cents!

LOL

Thanks for the great advice. I'm in the "keep it forever" category. Had my 1990 2G4R for 13 years and 195k miles, my 2003 Sequoia until trading it at 22 years and 297K miles to get my 6G4R. In both cases the engine and transmission were going strong - interior and body issues drove the new truck decision. (For Sequoia I had repeated issues with rear latch (opened with hanger for years), window motors (rear hatch, rear door, and moonroof) but it never slowed down on the road).

Will plan to follow your advice for Differential and Transfer Case (already on the 3-4K cycle for oil).

SO: Now I need the same sort of excellent instructions above for the Transfer Case oil change:>)

 

[brumey]

Very detailed procedure, thank you. I wonder what a dealer would charge to change front and rear? I am getting to the point of not wanting to do my own vehicle maintenance

 

[MikeD]

SO: Now I need the same sort of excellent instructions above for the Transfer Case oil change:>)

I think this is the transfer case drain plug but its not at all obvious to me where one would put oil into the transfer case. I'm sure some more googling will get me the answer but happened to be under the vehicle installing the skid plate that covers this area so took a few photos.

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