The factory exhaust brake on the 2019–2024 6.7L Cummins is one of the best towing features these trucks have — it holds you back on long grades, saves your service brakes, and makes heavy descents far less stressful. So it's a fair question before any turbo upgrade: will I lose it? With the right turbo, no.

How the exhaust brake works on a VGT truck

The 6.7 Cummins uses its variable-geometry turbo itself as the exhaust brake. By closing the VGT vanes, the turbo creates backpressure that slows the engine — no separate exhaust-brake valve required. That's why the technology you choose for your upgrade determines whether the exhaust brake survives.

Why a VGT drop-in keeps it

Because a variable-geometry drop-in like the TNT HE300VG 63mm retains the factory VGT mechanism and calibration, the exhaust brake keeps working exactly as designed. You get more airflow and lower EGTs from the larger compressor wheel while the vane-actuated braking function stays intact.

What loses the exhaust brake

Converting to a fixed-geometry turbo removes the variable vanes — and with them, the factory exhaust brake — unless you add a separate braking solution. For a towing truck, that's usually a step backward. The full trade-off is in HE300VG vs Fixed Geometry Turbo. If keeping the exhaust brake matters to you (and for most tow rigs it should), staying with a VGT drop-in is the answer.

Get the most from it

A healthy VGT and clean vanes keep the exhaust brake strong; soot-related vane sticking weakens it over time. Prevention is covered in How to Prevent HE300VG VGT Sticking, and if you're already seeing a weak exhaust brake or codes like P003A, start with HE300VG Actuator & VGT Problems. Pair the upgrade with supporting mods and good EGT habits from How to Lower EGTs on a 6.7 Cummins.

Frequently asked questions

Will I lose the exhaust brake with an upgraded turbo?

Not with a variable-geometry drop-in. The TNT HE300VG 63mm retains the factory VGT and exhaust brake.

How does the exhaust brake work on a 6.7 Cummins?

The variable-geometry turbo closes its vanes to create backpressure that slows the engine — the turbo itself is the exhaust brake.

Does a fixed-geometry turbo have an exhaust brake?

Not by default — removing the variable vanes removes the factory exhaust brake unless a separate system is added.

Why is my exhaust brake weak?

Often soot-related VGT vane sticking or actuator wear. See preventing VGT sticking and actuator problems.