2nd gen Tacoma (2005–2015) takes 75W-90 GL-5 in the transfer case; 3rd gen (2016–2023) takes Toyota's specific 75W transfer case fluid; capacity is about 1.05 quarts for both.
The Tacoma transfer case is a chain-driven part-time 4WD unit (RF1A on most years) sitting behind the transmission. It's a low-stress component until you cross water or drive thousands of miles on sealed pavement — both eventually contaminate or thermally degrade the fluid. Toyota's maintenance schedule lists "inspect" rather than a specific change interval, which is too vague for an off-road rig. Plan to drain and refill every 30,000 miles or any time you've been in water deep enough to cover the case.
Fluid choice differs by generation. On 2nd gen (2005–2015) the spec is 75W-90 GL-5 gear oil — the same fluid Toyota uses in the rear differential, and any reputable synthetic 75W-90 works. On 3rd gen (2016–2023) Toyota switched to a thinner 75W transfer case fluid (part 08885-81081). It is not the same fluid as the differentials. Filling a 3rd gen t-case with 75W-90 will technically work but is outside spec; Toyota's own service writers will sometimes do this when 75W is unavailable. For warranty work, stick with 75W. For everything else, decide based on what you can source.
The plugs use a 24mm socket. Fill plug sits high on the rear of the case, drain plug at the bottom. Open the fill plug first — universal rule for any drain-and-fill, and especially important here because the fill plug is angled awkwardly and sometimes seized. Drain into a pan, inspect for metal flakes (a small amount of fine paste is normal; chunks mean the chain is wearing).
Reinstall the drain plug with a fresh crush gasket at 27 ft-lbs. Pump new fluid through the fill until it overflows at the port edge — that's the level. Reinstall the fill plug with a fresh gasket at 27 ft-lbs. Drive the rig and recheck for seepage in a day or two.
| Part | Vendor | Est. price |
|---|---|---|
| Toyota Genuine 75W Transfer Case Fluid (quart, 3rd gen) | Toyota | ~$22 |
| Toyota Genuine 75W-90 GL-5 (quart, 2nd gen) | Toyota | ~$18 |
| Valvoline SynPower 75W-90 GL-5 (acceptable 2nd gen substitute) | AutoZone | ~$13 |
| Drain plug gasket | Toyota | ~$2 |
Written and maintained by an AZ wheeler and driveway wrencher. Always cross-reference your factory service manual — modifications affect vehicle safety and warranty. Work at your own risk.