Your cart is empty
Browse our catalog to find the parts you need.
These images are illustrative and may not match the product exactly. Always verify by part number — or confirm instantly with the assistant using a photo or VIN.
Chelsea · Fuel System
379639
In stock · ships from Knoxville
This is a Power Take-Off (PTO) shift indicator switch, often called a ball switch or sending unit.
Confirm the part fits before you buy. Applications and interchange numbers are researched and audited per part.
Verified fitment for 3 applications
Add your truck to see whether it's one of them
All confirmed applications for this part number.
Other applications
Other applications
Fits air shift cover pin-style PTO units. The inventory title 'SENDING UNIT' and category 'Fuel System' appear to be a misclassification by the supplier Post Onsite; this part is an electrical indicator switch for a transmission-mounted PTO, not a fuel system sender.
Part data verified against 3 catalog sources
Numbers this part supersedes or interchanges with. Showing 3 of 3.
Different year, make, or config? Get a confirmation against your truck in under a minute.
It is a normally open electrical switch that threads into the air shift cover of a Chelsea or compatible PTO unit to tell the driver when the PTO is engaged. When air pressure moves the shift mechanism, the switch closes and completes a circuit—usually turning on a dashboard light, sounding a buzzer, or enabling other equipment so the operator knows the PTO is in gear. These switches wear out over time from constant cycling, leading to intermittent or failed engagement signals, which is why they are commonly replaced during PTO troubleshooting or rebuilds.
Part Number: 379639
SENDING UNIT
Unit: ea
Dealer: Post Onsite
Compatibility, alternatives, and more
