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Drop-In 3rd Member Replacement for 2016-2023 Toyota Tacoma with E-Locker, 3.90 Ratio
The Yukon Gear YDAT8.75-390E is a complete, assembled 3rd member dropout assembly for the Toyota Tacoma T8.75 rear differential with electronic locker, built to a 3.90 gear ratio. This unit drops directly into your 2016-2023 Tacoma's rear differential housing and replaces the entire ring and pinion, carrier, and associated hardware as a single assembled unit. The YDAT8.75-390E is engineered for Tacoma owners who need a replacement third member that maintains E-Locker function or who want to change gear ratios to match a tire upgrade while keeping their factory electronic locker system intact. Yukon builds this assembly using high-quality ring and pinion gears, a matched carrier, and factory-reference OEM number 41110-0K630 to ensure correct fitment.
Key Features
- Complete Assembled 3rd Member — drop-in replacement for the Toyota T8.75 rear differential
- 3.90 Gear Ratio — ideal for 33-35 inch tire applications to restore factory driveability
- E-Locker Compatible Carrier — retains factory electronic locker engagement
- OEM Reference 41110-0K630 — correct fitment for 2016-2023 Tacoma E-Locker models
- Direct-Fit Dropout Design — replaces the entire 3rd member assembly without requiring housing removal
- Yukon Gear Quality — precision machined ring and pinion for quiet operation and long service life
| Specification | Detail |
|---|---|
| Part Number | YDAT8.75-390E |
| OEM Reference | 41110-0K630 |
| Brand | Yukon Gear and Axle |
| Differential Type | Toyota T8.75 Rear |
| Ring Gear Diameter | 8.75 inches |
| Gear Ratio | 3.90 |
| Carrier Type | E-Locker |
| Ring Gear Bolt Count | 12 |
| Spline Count | 34 |
| Assembly Type | Complete 3rd member (dropout) |
| Shipping Weight | Approximately 90.6 lbs |
| Shipping Dimensions | 19.4in L x 13.6in W x 12.1in H |
| UPC | 883584219063 |
What's Included
- 1x Assembled Toyota T8.75 third member dropout unit (ring gear, pinion, carrier, bearings)
- E-Locker carrier assembly for factory electronic locker compatibility
This Part Fits
| Year | Make | Model | Notes |
|---|---|---|---|
| 2016 | Toyota | Tacoma | With factory E-Locker rear differential, T8.75 |
| 2017 | Toyota | Tacoma | With factory E-Locker rear differential, T8.75 |
| 2018 | Toyota | Tacoma | With factory E-Locker rear differential, T8.75 |
| 2019 | Toyota | Tacoma | With factory E-Locker rear differential, T8.75 |
| 2020 | Toyota | Tacoma | With factory E-Locker rear differential, T8.75 |
| 2021 | Toyota | Tacoma | With factory E-Locker rear differential, T8.75 |
| 2022 | Toyota | Tacoma | With factory E-Locker rear differential, T8.75 |
| 2023 | Toyota | Tacoma | With factory E-Locker rear differential, T8.75 |
Frequently Asked Questions
-
Q: How do I know if my Tacoma has the T8.75 E-Locker differential?
A: Third-generation Tacomas with the TRD Off-Road and TRD Pro trims equipped with a rear electronic locker use the T8.75 differential. Open-differential models use the smaller 8-inch unit. Confirm your axle by checking the axle tag or decoding the factory option codes on your window sticker. -
Q: Does YDAT8.75-390E include the E-Locker motor or wiring?
A: No. The YDAT8.75-390E is the third member assembly including the ring gear, pinion, and E-Locker carrier. The factory E-Locker motor and wiring harness connect to the carrier after installation and are reused from your original unit. -
Q: Is 3.90 a good ratio for my tire size?
A: A 3.90 ratio is a popular upgrade for Tacomas running 33-35 inch tires over the factory 3.73 or 3.91 ratios. It restores low-end torque and cruise RPM to near-factory levels after a tire size increase. -
Q: Is this a direct bolt-in replacement?
A: Yes. The T8.75 is a dropout-style third member. Remove the axles and drain the fluid, unbolt and remove the existing third member from the rear housing, and install the YDAT8.75-390E in its place. No housing removal is required. - Q: Does professional installation require special tools?A: The dropout design simplifies installation compared to traditional cover-style differentials. However, correct torque values and fluid fill are required. Professional installation by a drivetrain shop is recommended.
-
Q: What gear oil does the Toyota T8.75 use?
A: Toyota specifies 75W-90 GL-5 gear oil for the T8.75. Use a quality synthetic 75W-90 and fill to the bottom edge of the fill plug hole. If your unit has a limited-slip carrier, add the correct friction modifier — the E-Locker carrier does not require a friction modifier. -
Q: Will my factory E-Locker button still work after installation?
A: Yes, provided the factory E-Locker motor and wiring are transferred from the original unit to the YDAT8.75-390E carrier. The electronic engagement mechanism is maintained by the E-Locker carrier design. -
Q: What is the warranty on the YDAT8.75-390E?
A: Yukon Gear covers this assembly with a Lifetime Limited Warranty. Drivetrain components also qualify under Magnuson-Moss Warranty Act consumer protections.
Installation Notes
- Drain the rear differential before removing the third member
- Remove both rear axle shafts to allow third member removal from the housing
- Unbolt the existing third member and carefully withdraw it from the housing
- Transfer the factory E-Locker motor from the original carrier to the YDAT8.75-390E carrier before installation
- Install the YDAT8.75-390E and torque all fasteners to factory specification
- Reinstall axle shafts, fill with 75W-90 GL-5 gear oil, and test E-Locker function before returning to road use
California Prop 65 Warning
WARNING: This product can expose you to chemicals including lead and lead compounds, which are known to the State of California to cause cancer and birth defects or other reproductive harm. For more information go to www.P65Warnings.ca.gov.
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