4-speed automatic (4AT)
A four-speed automatic — a meaningful improvement over the 3AT with an overdrive ratio, found on the DA63T, HA6/HA7, and S200P/S210P.
How it works
A four-speed hydraulic automatic transmission. An improvement over the 3AT with tighter ratio spacing and an overdrive fourth gear. Found in the DA63T, HA6/HA7, and S200P/S210P generations as the automatic option.
Pros and cons
Advantages
- ✓ No clutch — accessible to all drivers
- ✓ Tighter ratios than 3AT — less power loss between gears
- ✓ Fourth gear is overdrive — better highway cruising than 3AT
- ✓ More modern and reliable than the older 3AT
Disadvantages
- ✗ Still consumes more power than a manual — a 44hp engine feels noticeably weaker
- ✗ No access to diff-lock or low-range trims (automatic trucks don't receive these features)
- ✗ 4AT trucks command a price premium over manual equivalents in Japan — less value for off-road buyers
- ✗ Fluid and filter service is critical and often skipped on used imports
Maintenance schedule
| Item | Specification |
|---|---|
| Service interval | Inspect fluid on arrival; replace every 40,000 km |
| Fluid specification | Manufacturer-specified ATF — verify for your specific model and year (Suzuki, Honda, Daihatsu each specify different fluids) |
Common issues
| Issue | Severity | Notes |
|---|---|---|
| Fluid neglect | Moderate | The single most common 4AT problem on used imports: fluid that has never been changed. Dark, burnt-smelling ATF causes rapid clutch pack and seal wear. Flush and refill on arrival — do not wait. |
| Delayed gear engagement | Moderate | Hesitation between Park/Neutral and Drive, especially when cold. Often fluid-related in early stages; advanced cases indicate worn clutch packs. |
| Shudder on light throttle | Minor | Common on 4ATs with degraded fluid — the torque converter lock-up clutch shudders on light throttle at cruise. Usually resolved by a fluid change with the correct spec fluid. |
Recommended for
Buyers who need automatic and want more refinement than a 3AT — accept that off-road capability (diff-lock, low range) is not available
How the 4AT compares — and who should choose it
The 4AT is a genuine improvement over the 3AT. The overdrive fourth gear makes highway cruising tolerable and the tighter overall ratio spread means the engine works more efficiently between shifts. If you need an automatic and are buying from the DA63T, HA6/HA7, or S200P/S210P generation, the 4AT is the right automatic to choose.
Against the 5MT, the 4AT loses on power delivery, fuel economy, and off-road grade access. Diff-lock and low-range trims are manual-only — if you want those features, you must buy a manual regardless of personal preference.
Against the CVT, the 4AT is more proven, cheaper to repair, and appropriate for hauling work. The CVT is smoother and more fuel-efficient in city driving, but it lives in newer trucks (S500P, DA16T) that most US buyers cannot import yet.
Choose the 4AT if you need automatic, you are targeting a DA63T, HA6/HA7, or S200P/S210P, and off-road capability (diff-lock, low range) is not a priority. It is a good automatic; it just cannot match the 5MT for buyers who want every truck capability unlocked.