Tuff Torq K46 vs K57 vs K58 vs K62/K66 vs K72: Specs Compared
Tuff Torq makes the hydrostatic transaxle in a huge share of lawn and garden tractors. The model code on the label (K46, K57, K58, K62, K66, K72, T40, TL-200) tells you its size class. Here's how they compare, using Tuff Torq's published specs, and what that means if you're replacing one.
The short version
- TL-200: entry-level lawn tractors (Cub Cadet XT1, many Craftsman). The lightest-duty unit.
- K46 and T40: the everyday lawn-tractor transaxle (John Deere D/E/LA/S series, Husqvarna YTH, Cub Cadet, Craftsman). 0.75" axles, powder-metal gears.
- K57 / K574: the same footprint as the K46 with higher ratios and more torque; the K574 goes in 4WD machines.
- K58: steel gears and 1" axles for estate tractors such as the John Deere X300 series.
- K62 / K66 / K664: premium yard and estate tractors with 10 cc pump and motor, 1" axles, optional diff lock and hydraulics. The K66 adds steel gears and up to 310 lb-ft.
- K71 / K72: garden tractors (John Deere X500/X700 class) with 18/23 cc, 405 lb-ft and an external filter.
- TZ / TZT: zero-turn units, sold as left/right pairs. See the TZ/TZT hub.
Side-by-side specs
| TL-200 | K46 | K57 | K58 | K62 | K66 | K72 | |
|---|---|---|---|---|---|---|---|
| Typical machine | Entry-level riding mowers, lawn tractors | Rear engine riding mower, lawn tractor | Riding mowers, larger lawn tractors, estate tractors, 4WD/articulating mowers | Estate tractors, small garden tractors, heavier lawn tractors | Larger premium yard tractors, estate tractors, light-duty garden tractors | Larger premium yard tractors, estate tractors, light-duty garden tractors | Yard tractor, estate tractor, garden tractor (larger properties, light garden work) |
| Ratio | 28.04:1; 21.53:1 | 28.04:1; 21.53:1 | 31.68:1; 28.04:1; 21.53:1 | 31.44:1 | 26.90:1; 18.65:1 | 37.22:1; 22.19:1 | 23.37:1 |
| Rated axle torque | 28.04:1 = 176.4 Nm (130 lb-ft); 21.53:1 = 138.6 Nm (102 lb-ft) | 28.04:1 = 231.4 Nm (171 lb-ft); 21.53:1 = 177.7 Nm (131 lb-ft) | 31.68:1 = 255 Nm (188 lb-ft); 28.04:1 = 235.4 Nm (174 lb-ft); 21.53:1 = 180.7 Nm (133 lb-ft) | 294 Nm (217 lb-ft) | 26.90:1 = 294 Nm (217 lb-ft); 18.65:1 = 203 Nm (150 lb-ft) | 37.22:1 = 420 Nm (310 lb-ft); 22.19:1 = 250 Nm (185 lb-ft) | 23.37:1 = 549 Nm (405 lb-ft) |
| Max tire | 28.04:1 = 508 mm (20 in); 21.53:1 = 457 mm (18 in) | 28.04:1 = 508 mm (20 in); 21.53:1 = 457 mm (18 in) | 31.68:1 = 559 mm (22 in); 28.04:1 = 508 mm (20 in); 21.53:1 = 457 mm (18 in) | 584 mm (23 in) | 26.90:1 = 584 mm (23 in); 18.65:1 = 457 mm (18 in) | 37.22:1 = 584 mm (23 in); 22.19:1 = 457 mm (18 in) | 23.37:1 = 610 mm (24 in) |
| Pump / motor | 7/10 cc/rev | 7/10 cc/rev | 7/10 cc/rev | 7/10 cc/rev | 10/10 cc/rev | 10/10 cc/rev | 18/23 cc/rev |
| Axle shaft | 19.05 mm (0.75 in) | 19.05 mm (0.75 in) | 19.05 mm (0.75 in) | 25.4 mm (1.0 in) | 25.4 mm (1.0 in) | 25.4 mm (1.0 in) | 25.4 mm (1.0 in) |
| Gears | Heat-treated Powder Metal | Heat-treated Powder Metal | Heat-treated Powder Metal; Heat-treated Steel gears available as optional upgrade | Heat-treated Steel Gears | Heat-treated Powder Metal Gears; Heat-treated Steel Gears available option | Heat-treated Steel Gears | Heat-treated Steel Gears |
| Dry weight | 12.5 kg (27.6 lb) | 12.5 kg (27.6 lb) | 12.5 kg (27.6 lb) | 15.3 kg (33.7 lb) | 23 kg (50.7 lb) | 23 kg (50.7 lb) | 27.5 kg (60.5 lb) |
Source: Tuff Torq product specifications. Individual versions vary in ratio, pulley, fan and control-arm setup.
Can I swap one model for another?
Generally no. Tuff Torq's own guidance is to rebuild or replace with the same model. For example, a K46BT does not replace a K46AC, even within the K46 family. Axle length, pulley, control arm, brake linkage and mounting differ between versions. Replace what your tractor shipped with unless the tractor maker approves a different unit. The exception is a supersession: Tuff Torq sometimes replaces a part number with an updated one for the same model, which our listings show as "supersedes".
How to tell which one you have
Read the white barcode label on the back of the transaxle (some tractors repeat it under the seat). It shows the model, the 11-digit Tuff Torq part number and the serial number. Don't rely on the owner's manual alone: Tuff Torq warns that manuals can be misprinted. No label? Use our lookup by mower model or part number guide.
Need the part?
We sell new, genuine Tuff Torq units, repair kits and Tuff Tech fluid, priced at least 5% under other sellers with free shipping to the lower 48 (Low Price Guarantee). Not sure which one you need? Send the numbers from your unit's label through the Tuff Torq Part Finder and we'll confirm it, usually the same business day.
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