How to Read a PTO Model Code (442XLAHX-V3XK Explained)
Quick answer: A PTO model code is read from left to right. The leading digits give the series family. The letters that follow describe output type, port position, control provision and shift configuration. The trailing digits give the speed ratio, and the final letter block is the revision or porting variant. Read all four blocks and you know exactly what a unit is — and what will replace it.
Why codes exist
Two PTOs from the same family can carry different output flanges, different port positions and different gear ratios. Describing that in words would be unusable in a catalogue, so manufacturers compress it into a code. Once you know the logic, the code becomes the fastest identification tool you have.
Breaking down a real code
Take a representative code from the 442 family: 442XLAHX-V3XK.
| Block | Example | What it describes | Why it matters |
|---|---|---|---|
| 1. Series | 442 | The mechanical family — housing size, mounting footprint, general torque class | Decides whether the unit will bolt to your transmission pad at all |
| 2. Configuration letters | XLAHX | Output type, port arrangement, control and shift provision | Decides whether the pump flange and hose routing will work |
| 3. Ratio digits | V3 | Drive ratio between transmission and PTO output | Decides output speed and therefore pump flow at engine rpm |
| 4. Revision suffix | XK | Iteration or porting variant within the same configuration | Two units one letter apart may not interchange |
Block 1 — the series digits
The first digits are the family. Reading them tells you the mounting footprint and puts you in the right section of any catalogue. If the series digits do not match, stop: nothing downstream will save the fitment.
Block 2 — the configuration letters
This is the block that gets misread most often. Letters here encode:
- Output type — direct-mount pump flange or shaft output
- Port position — which face the hydraulic connections exit from, and therefore how hoses route around the chassis
- Control provision — air, cable or electric engagement, and whether the housing is machined for it
- Shift configuration — single or dual acting, and the mechanical arrangement of the engagement mechanism
Because a single letter can carry one of these distinctions, transcribing a code by eye from a dusty nameplate is a genuine risk. Photograph the plate, then zoom in.
Block 3 — the ratio
PTO drive ratio sets output speed relative to transmission input. That matters directly for pump flow: the same pump on two different ratio PTOs delivers two different flow rates at the same engine speed. If your hydraulic system is running slow or running hot, ratio is one of the first things to check.
Block 4 — the revision suffix
The trailing letters identify the variant. Manufacturers revise porting, sealing and internal details over time, and the suffix is how those revisions are tracked. Never assume a suffix difference is cosmetic.
A practical decoding workflow
- Clean the nameplate and photograph it at high resolution.
- Read the series digits. That is your family.
- Record the full configuration block character by character.
- Note the ratio digits and the revision suffix separately.
- Write the transmission make and model next to the code.
- Send all six data points to your supplier for confirmation.
Frequently asked questions
Can I replace a PTO with a different revision suffix?
Only after confirming what changed between revisions. Some suffix steps change only sealing or fastener details and are interchangeable; others change porting or output geometry. Confirm by specification, never by appearance.
What if my nameplate is unreadable?
Fall back on the transmission model plus physical measurement of the mounting pad, hole spacing, output flange and port positions. Those measurements usually identify the family and narrow the variant.
Does the model code tell me the torque rating?
It identifies the family and configuration, which sets the general torque class. For an exact figure, match the full code against the manufacturer's specification data.
Why do two PTOs with the same series look different?
Because the configuration block and suffix differ. Output flange size, port position and control provision all change the external appearance of the housing.
Is a longer code always a heavier PTO?
No. Code length reflects how much configuration information a family needs to describe, not the unit's torque class.
Need a code read for you?
Send a clear photo of the nameplate together with the transmission model, and we will confirm the matching unit. Browse the full PTO range or the Chelsea-compatible replacements.
Need help confirming fitment? Send us your transmission model, the PTO number on your current unit, and a photo of the mounting pad. We check bolt pattern, shaft interface and torque rating before you buy — contact the KT Auto Parts team.
KT Auto Parts supplies new aftermarket replacement parts. All brand and model names are used for reference and identification purposes only and remain the property of their respective owners.