THE ACREAGE EQUIPMENT FIELD GUIDE
Gear or HST: when the engine figure changes and the PTO figure does not
Tractor makers do not handle transmissions the same way in their spec sheets. Some list one engine figure and a lower PTO figure for the HST. Kubota’s MX sheet does the reverse: the HST lists more engine power and the same PTO power. Which pattern a tractor follows decides whether engine-rated or PTO-rated attachments see a difference between transmissions.
By Acreage Equipment · Reviewed November 8, 2026 · Specification research, not a field test
THE DECISION IN NUMBERS
Engine and PTO figures by transmission
Values from this site’s tractor profiles and the Kubota MX specification sheet (May 2025) and TC860-1971-9 manual, reviewed November 8, 2026. Engine figures for the MX are gross SAE J1995.
Scroll the table sideways on smaller screens.
| Tractor | Engine hp: gear / HST | PTO hp: gear / HST | Which differs |
|---|---|---|---|
| Kubota MX4900 | 50.3 / 51.8 | 41.3 / 41.3 | Engine |
| Kubota MX5400 | 55.5 / 57.0 | 46.5 / 46.5 | Engine |
| Kubota L3902 | 37.5 / 37.5 | 32.1 / 30.3 | PTO |
| Kubota L4802 | 48.4 / 48.4 | 40.5 / 39.0 | PTO |
| KIOTI CK3520 | 34.9 / 34.9 | 30.9 / 28.9 | PTO |
| Mahindra 1635 | 36.2 / 36.2 | 27.6 / 26.0 (shuttle / HST) | PTO |
Sources for this decision table (2)
- Kubota MX specification sheet (PDF modified May 14, 2025) ↗Printed pp16–17: gross SAE J1995 and net SAE J1349 power, PTO power, Category I & II, lift at 24 in., weights
- Kubota TC860-1971-9 operator manual, MX4900/MX5400/MX6000 (©2019, hosted by Garton) ↗Printed pp23–24 MX4900 specifications; printed p31 implement limitations (flail 72 in. / 1,100 lb)
The MX pattern
Kubota’s May 2025 MX sheet lists the MX4900 gear at 50.3 gross hp and the HST at 51.8, and the MX5400 gear at 55.5 and the HST at 57.0. Both transmissions share one PTO figure: 41.3 and 46.5 hp. Kubota does not explain the difference. The manual also lists different engine speeds for 540 at the PTO: 2,700 rpm on the gear tractor and 2,660 on the HST.
The more common pattern
Other tractors on this site list one engine figure and two PTO figures. Kubota’s L3902 lists 37.5 engine hp with 32.1 PTO hp (gear) and 30.3 (HST); the L4802 48.4 with 40.5 and 39.0. KIOTI’s CK3520 lists 34.9 with 30.9 (manual) and 28.9 (HST). Mahindra’s 1635 lists 36.2 with 27.6 (shuttle) and 26.0 (HST). In each case the HST is lower at the PTO.
Which attachments notice
When only the engine figure differs, engine-rated attachments see the difference: on the MX4900, BX72S’s 50-hp minimum is cleared by 0.3 on the gear tractor and 1.8 on the HST (gross). PTO-rated attachments give the same answer on both. When only the PTO figure differs, the reverse applies: on the L3902, a 31-PTO-hp minimum would be met by the gear tractor and not the HST.
What to check
Read the transmission column, not just the model column. Note which figure changes between transmissions and which attachments rate on that figure. If a maker publishes only one figure for both transmissions, ask whether it was measured on one of them.
Take these questions with you.
- Does my tractor’s spec sheet list different engine or PTO figures for gear and HST?
- Which figure does each attachment I am considering rate on?
- If one figure covers both transmissions, was it measured on mine?
- Does the engine speed for 540 PTO rpm differ between transmissions?
Keep these questions with your exact tractor and attachment details.
Use these questions in my seller briefFOLLOW THE NUMBERS
Sources & documentation
Research record reviewed November 8, 2026. Confirm the current manual and the exact revision supplied with your machine.
- Kubota MX specification sheet (PDF modified May 14, 2025)Printed pp16–17: gross SAE J1995 and net SAE J1349 power, PTO power, Category I & II, lift at 24 in., weights
- Kubota TC860-1971-9 operator manual, MX4900/MX5400/MX6000 (©2019, hosted by Garton)Printed pp23–24 MX4900 specifications; printed p31 implement limitations (flail 72 in. / 1,100 lb)
- Kubota 2026 Full Line Catalog — MX Series, printed p22 / PDF p24MX table: gross and PTO horsepower, tractor weight
- Wallenstein BX72S official U.S. pageEngine HP Range; Mounting System (Cat I and II); Total Weight; Discharge Chute Height
- Woodland Mills official U.S. product page — Capacity and hydraulic infeed sections; current price
- Woodland Mills WC68 operator manual, Rev C, 28-May-2024 — Printed p9 product/shipping weights; p12 Cat 1 and PTO range; operation/setup sections
- Official U.S. WC88 page: price, capacity and drive system
- Current linked WC88 operator manual, Rev C, 22-Aug-2022
- BX72S official support page — current operator/setup documents
- BX-S operator manual Z97085_En, Rev Jan-2025 — pp14,18–22,26,28,30,40
- PTO shaft instructions Z97844_En, Rev Aug-2024 — tractor/quick-hitch sizing
