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.

PAI · Air System
EM34550
In stock · ships from Knoxville
The EM34550 is a PAI tractor protection valve, a TP-5 type air brake component used on heavy-duty trucks.
Confirm the part fits before you buy. Applications and interchange numbers are researched and audited per part.
Verified fitment for 1 applications
Add your truck to see whether it's one of them
All confirmed applications for this part number.
Universal fit
Standard TP-5 tractor protection valve; fits many heavy-duty truck makes including Mack, but no specific application list is provided. Commonly used in tractor air brake systems.
Part data verified against 5 catalog sources
Numbers this part supersedes or interchanges with. Showing 10 of 10.
Different year, make, or config? Get a confirmation against your truck in under a minute.
It controls the flow of air to the trailer brakes, transmits brake signals from the tractor to the trailer, and protects the tractor's air supply in the event of a trailer breakaway or sudden separation of the connecting lines. This valve is commonly replaced when it develops air leaks, fails to hold pressure, or causes the trailer brakes to not apply or release properly. It is compatible with multiple truck makes and is a direct replacement for Mack 745-288605 and other OEM numbers.
Part Number: EM34550
TRACTOR PROTECTION VALVE 288605
Dealer: Post Onsite
Compatibility, alternatives, and more
Parts commonly needed alongside air system