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The only engine brake for ISB & PX-7 Diesel Engines

As the only true engine brake available for the class 3-5 truck market, Pacbrake LoadLeash provides big-rig engine braking performance. In addition to enhanced vehicle control and reduced brake fade, Pacbrake LoadLeash can extend service brake life by up to 500%.

Designed for the heavy hauler!

LoadLeash Highlights

  • For Cummins ISB 5.9L, 6.7L & Paccar PX-7 Engines
  • Provides over 300 retarding horsepower*
  • Lightweight support housing
  • Extends the life of your service brake by up to 5 times
  • LoadLeash offers an increase in safety, ride comfort & saving

LoadLeash Features & Benefits

  • PERFORMANCE Provides over 300 retarding horsepower*
  • DESIGN Lightweight support housing replaces the factory valve cover spacer with no valve cover height increase
  • SAVINGS Extends the life of your service brake by up to 5 times while reducing truck & trailer brake wear
  • WARRANTY 18 month warranty for new vehicles, 12 month/100,000 mile warranty on parts and labor for used vehicles

*P67 Applications

LoadLeash Specifics

  1. ALUMINUM SUPPORT HOUSING Lightweight support housing replaces the factory valve cover spacer with no valve height increase
  3. HYDRAULIC CONTROL SOLENOID One per brake assembly

Quick & Controlled Braking For Heavy Duty Trucks Just Got Easier!

LoadLeash kits include:

  • Automotive grade wiring with abrasion protection
  • Precision cast aluminum valve cover spacer
  • IP67 rated controller housing
  • Forged heavy duty bridges
  • SAE & ISO rated fittings
  • Intelligent controller
  • SAE rated hose


If I install the LoadLeash Engine Brake on my truck will it make that neat " Jake Brake" sound?

It will not. This style of the engine brake is what the industry calls a "weeper" engine brake, and it similar sounding to an exhaust brake.
When engaged, it holds an exhaust valve slightly cracked, slowing the engine by forcing the pistons to compress and suck air through a small opening, similar to the concept of blowing and sucking air through a narrow straw.
Compression release style engine brakes have an exhaust valve mechanism that it timed to the engine valve train to "pop" off the compression at a certain time which gives off the loud exhaust note, similar to when a pellet gun is compressed then fired.

Can I use the LoadLeash Engine Brake with an aftermarket turbocharger?

Yes, but you must also use an exhaust brake to create the back pressure needed to allow theLoadleash to perform at its maximum efficiency.

Can I install LoadLeash Engine Brake if I have ARP head studs?

Yes, you can. The Loadleash housing has provisions in place to allow the use of aftermarket head studs and nuts.
You can also use ARP custom aged head studs but must purchase the Pacbrake stud kit also made by ARP specially for this application. Part number P55127.

Can I use this LoadLeash Engine brake with my performance tuner?

Yes, your performance tuner will have no effect on the engine brake performance.

My truck has had an emissions delete, can I still install this LoadLeash Engine Brake?

As long as an exhaust brake or VGT brake is still present, an emissions delete will have no effect on the engine brake performance.

How much braking power will increase over the factory exhaust brake with the use of LoadLeash Engine Brake?

Pacbrake’s LoadLeash, used in tandem with the VGT exhaust braking feature, will result in a 40% increase in retarding HP when measured at the rear wheels (assuming 60 HP of drivetrain friction).

LoadLeash + VGT = 360RHP | VGT Only = 210RHP

Do I always have to turn on the Exhaust brake button to make this brake work properly?

Yes, ideally you should always run the exhaust brake in combination with the LoadLeash for it to perform at its peak.
Using the LoadLeash without the exhaust brake on will not harm the engine but it will not brake as hard as with the exhaust brake activated.

Do the municipal street signs that state "the use of engine brakes are strictly prohibited in urban areas" apply to my LoadLeash Engine Brake?

No, the LoadLeash, although an engine brake, gives off very little noise or exhaust note.

I don't have an Exhaust Brake, can I still use a LoadLeash Engine Brake?

Yes, you can but it will not perform to its maximum braking performance.

Warranty Registration

Register your product for warranty HERE.