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.

Automann · Tools & Supplies
579.KP5681-T
In stock · ships from Knoxville
This is a king pin gauge tool designed for checking wear on the king pin of a semi-trailer.
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
Diagnostic tool for measuring king pin wear, not a vehicle-specific part. Typically used with standard 2-inch king pins (common on commercial semi-trailers), but exact compatibility should be verified by the user.
Part data verified against 5 catalog sources
Numbers this part supersedes or interchanges with. Showing 2 of 2.
Different year, make, or config? Get a confirmation against your truck in under a minute.
The king pin is the component that locks into the fifth wheel coupling on a tractor; over time it can wear undersize and become unsafe. This go/no-go gauge quickly verifies whether the king pin diameter remains within service limits, indicating if replacement is necessary to prevent coupling failure. It is an essential inspection tool for heavy-duty truck and trailer maintenance shops.
Part Number: 579.KP5681-T
KING PIN GUAGE
Unit: ea
Dealer: Knox Trailers
Compatibility, alternatives, and more