6.7 Cummins Cab & Chassis Delete: Why a Pickup Kit Won’t Fit

For off-road / competition use only. Not legal for on-road use in emissions-regulated areas. Check your local, state, and federal laws before modifying any emissions-related component.

The short answer is the one that trips up most owners: the engine is the same, but the truck is not. A 6.7L Cummins in a 3500/4500/5500 Cab & Chassis shares its block, head, pistons, and crank with a Ram pickup of the same generation — but the delete kit that fits one will not bolt onto the other. The real divider is the frame, the exhaust routing, and the Aisin transmission.

Buy the wrong pipe and it won’t clear the commercial crossmembers. Buy the wrong tune and the transmission de-fuels on you the moment you ask for power. Here’s exactly where the fitment actually breaks down — and why that “pick up model only” note on the instructions is the thing most owners misread.

Is It Even the Same Engine?

A 6.7L Cummins is a 6.7L Cummins from the head gasket down. The block, cylinder head, pistons, and crankshaft are the same casting between a pickup and a chassis cab of the same generation. What differs is everything bolted around it:

• Aftertreatment — the DPF/SCR canister layout and pipe routing differ, because the frame behind the cab is a different animal.

• Injectors and turbo — the hardware is largely shared, but the calibration is not. The exhaust manifold itself is visibly different on a chassis cab — wider, with different mounting points.

• Transmission — pickups run the 68RFE (or an optional Aisin); chassis cabs are Aisin only, and that single fact rewrites the entire tuning conversation.

So “can I use pickup parts on a chassis cab?” is more precise than it sounds: the engine internals don’t care, but the exhaust, the frame, and the transmission absolutely do.

Why the Chassis Cab Makes Less Power (on Purpose)

Here’s a detail that catches owners off guard: the chassis cab is detuned from the factory.

• A 2018 Ram 3500 pickup 6.7L Cummins is rated 385 hp and 930 lb-ft.
• The 2019 chassis cab version of the same engine is rated 360 hp and 800 lb-ft.

Ram doesn’t do that by accident. The chassis cab is meant to live its life as a hard-working truck, so it’s tuned conservatively for longevity (lower cylinder pressures, lower heat, and longer service life). It’s still a monster, but the horsepower ceiling starts lower here — and the transmission keeps it there.

Where the Fitment Actually Breaks Down

The cleanest way to think about it is to split the kit into two halves, because they fail for different reasons.

The EGR Side Is Mostly Shared

The EGR valve, cooler, and block-off plates bolt directly to the engine. Since the engine block is identical, the plates land the same way.

• The one wrinkle: On a chassis cab, one EGR coolant line runs down to the block and comes out from underneath (a reach-and-find step a pickup doesn’t have). It’s a fitment detail, not a showstopper.

The DPF/Exhaust Side Is Chassis-Specific

This is where the two trucks genuinely part ways:

• Pickup: Uses a tube-style frame that dips down at the cab, leaving plenty of room to hide wiring and route a pickup exhaust.

• Chassis Cab: Uses a heavy-duty C-channel frame that runs flat and straight to accommodate flatbeds or service bodies. It also carries heavier leaf packs, overload springs, and a factory rear anti-sway bar.

• The Result: The Cab & Chassis delete pipe is mandrel-bent to clear commercial frame crossmembers, the fuel tank, and the rear axle. A pickup DPF pipe will not line up here, and vice versa.

The Aisin Transmission: The Wall You Don’t See Coming

Chassis cabs run the Aisin automatic, and its TCM has strict torque-limiting parameters designed to protect the transmission.

Because software to fully unlock the C&C Aisin TCM essentially doesn’t exist, the realistic tune ceiling is a tow tune (roughly 50 hp). A full-power delete tune (100+ hp) that a pickup happily handles will cause a chassis cab to de-fuel itself and fight the transmission.

Platform	Transmission	Realistic Tune Ceiling	Why
2500/3500 Pickup	68RFE (or optional Aisin)	Full delete tunes, 100+ hp	68RFE widely supported
3500/4500/5500 Cab & Chassis	Aisin only	Tow tune (~50 hp)	TCM torque limiting, no unlock software

So a chassis cab delete is a reliability and driveability play, not a horsepower play. You’re removing the regen cycles, the soot ingestion, and the EGR cooler failure point — not chasing a dyno number. 

Why the Frame Is the Real Divider

If you’ve ever looked at a pickup next to a chassis cab from underneath, the difference is immediate — and it’s the whole story.

• Pickup = tube-style frame. Built to carry a bed, it dips down at the cab and changes section along its length. Plenty of room to hide wiring and route a pickup exhaust, but it’s not meant to be upfitted.

• Chassis cab = C-channel frame. It runs flat and straight from the back of the cab all the way to the tail, on purpose. That straight rail is what lets a flatbed, service body, or dump body bolt on without a fight.

The chassis cab also carries hardware the pickup doesn’t: a heavier leaf pack with overload springs, a factory rear anti-sway bar, and a much higher payload rating — north of 6,300 lbs on a 3500 chassis cab. That extra capability is paid for with a different frame, and a different frame means a different exhaust path underneath it.

What “Pick Up Model Only” Actually Means

This is the note that stops a lot of owners before they even start, and it shouldn’t.

You’ll see a 2013–2018 Ram Cummins EGR delete instruction set marked “pick up model only.” That phrase is a note about the document, not the coverage. It tells you which body style the photographs and the step-by-step order were shot on — the pickup was on the lift when they took the pictures. It is not the record that decides whether the parts bolt to your engine.

Two records answer two different questions:

• The fitment record (the coverage table) answers “does this kit fit my truck?”
• The instruction set answers “what did this job look like on the truck it was documented on?”

Read the fitment record for coverage, and use the instruction set for procedure — following the sequence while reading the locations off your own truck. Mix the two up and you’ll talk yourself out of a kit that fits, or order one that doesn’t.

The Honest Numbers: What a Chassis Cab Delete Actually Changes

Every delete article on the internet throws horsepower numbers around. Here’s the version that survives a chassis cab reality check, with the numbers pinned to their source.

Metric	2500/3500 Pickup	3500/4500/5500 Chassis Cab
Factory rating	385 hp / 930 lb-ft	360 hp / 800 lb-ft (detuned)
Transmission	68RFE (or optional Aisin)	Aisin only
Tune ceiling	100+ hp (full tuner support)	~50 hp tow tune (Aisin de-fuels past it)
Does the delete add power?	No — the tune does	No — the tune does
What you actually gain	Power + reliability	Reliability only

The Rule Every 6.7 Cummins Follows

The delete itself doesn’t add horsepower — the tune does. Removing the DPF and EGR removes restriction and failure points; the power comes from the calibration you flash afterward. That’s the same rule as every other 6.7 Cummins.

What the Aisin Caps You At

• On a chassis cab, that tune is capped at roughly 50 hp. The Aisin’s torque-limiting TCM de-fuels the truck past a tow tune, and there’s no software to unlock the C&C Aisin.
• So the 100+ hp delete numbers a pickup owner posts are real — but they’re a pickup’s numbers, on a pickup’s transmission.

What You Actually Gain

Reliability, and it’s not nothing. Three specific failures stop happening at once:

• The regen cycle stops wasting fuel and diluting oil.
• Soot stops caking the intake manifold.
• The EGR cooler stops waiting to crack and dump coolant into a cylinder.

On a truck that idles long and works hard — exactly how a chassis cab spends its life — that’s the delete that pays for itself.

Built for the Commercial Chassis: The TruckTok Solution

This is why a chassis cab needs a chassis-specific kit, not a pickup kit adapted after the fact.

If you drive a 2013–2019 Ram 3500/4500/5500 Cab & Chassis, you need a 2013–2019 6.7 Ram Cummins Cab & Chassis 4" DPF & EGR Delete Kit designed specifically for your truck: 

• 4" free-flow DPF delete race pipe, precision mandrel-bent to clear the commercial frame crossmembers, fuel tank, and rear axle. This is the part that won’t interchange with a pickup pipe.

• Heavy-duty solid block-off plates — CNC-machined billet aluminum and steel, sealing against factory manifold pressure. The exhaust plate bolts to the rear passenger-side manifold.

• Commercial-grade EGR delete — removes the EGR valve and cooler, stopping intake soot and eliminating the internal cooler leak risk.

• 409 stainless construction with thick mounting flanges, built to take commercial towing and work-site abuse.

Fitment is 2013–2019 3500/4500/5500 Cab & Chassis, and it explicitly does not fit regular pickup-bed Ram 2500/3500 — because the frame rails, crossmembers, and pipe routing are genuinely different. As always, a delete tune is mandatory; the hardware without a calibration throws codes and drops the truck into a reduced-power mode.

The Install: A Chassis Cab Walkthrough

The job is the same shape as a pickup delete — remove the EGR, remove the DPF/SCR, flash the tune — but the details diverge in ways worth knowing before you’re on your back. This is the order that matters, because a 6.7 Cummins delete done out of sequence leaves the ECM throwing codes the moment it can’t find the hardware.

Tools You’ll Need

• 8mm, 10mm, and 15mm sockets, plus a 13mm for the exhaust manifold bracket — with a few extensions and a wobble/swivel joint for the bolts you can’t see.
• Torque wrench, penetrating oil, and a wire brush for the exhaust fasteners that have heat-seized.
• A coolant catch pan and fresh coolant to refill — you’re opening the cooling system when the cooler comes out.
• A cut-off tool for the exhaust pipe. Unlike a pickup, the chassis cab pipe is cut to length for your cab-to-axle dimension.
• A magnet on a stick and an aimable shop light. Half this job is done by feel in a space you can’t see into, and the bolt you drop will land somewhere your fingers can’t reach.

Step 0 — Flash the Tune First

Sort the tuning before you turn a single wrench. On a 2018+ truck, install the Security Gateway bypass cable and flash the delete calibration while the truck is still complete, so the ECM is already expecting the emissions hardware to be gone. The bypass repins two wires at the DLC and twists into the gateway module connector — a half-hour harness job. This is the step that prevents the immediate limp mode.

Step 1 — Remove the EGR Valve and Crossover Tube

The tube runs from the EGR valve to the EGR cooler, held by two 10mm bolts, one 8mm bracket, and one EGR temperature sensor connector. A wobble extension makes the 8mm reachable. Support the tube as the last fastener comes out so it doesn’t sag and bind.

Step 2 — Remove the EGR Cooler

Two 10mm bolts and one 15mm on the exhaust side, plus the coolant lines. This is the chassis cab-specific step: one coolant line runs down to the block and comes out from underneath, not from the top. You’ll reach it with an 8mm buried low on the block — a pickup doesn’t have this step, so don’t assume the job is done when the top is clear.

Step 3 — Install the Block-Off Plates

The exhaust plate bolts to the rear passenger-side manifold, and the intake plate seals the driver-side intake port. Use a fresh gasket or copper spray — exhaust gaskets don’t like being reused, and a leak here undoes the whole job. Clean the mating surface before the plate goes down, and bring the fasteners down evenly rather than snugging one corner first.

Step 4 — Drop the DPF/SCR and Hang the Delete Pipe

Disconnect the sensors and the DEF injector line, unbolt the factory canister, then cut the new 4" race pipe to your cab-to-axle length and bolt it to the factory hanger locations. A 60" CA truck is not the same as an 84" CA truck — measure before you cut, and keep the pipe clear of the crossmembers and fuel tank it was bent to clear.

Step 5 — Refill, Bleed, and Road-Test

Refill the coolant, bleed the system, and tuck-and-zip-tie the orphaned connectors so they aren’t flopping under the cab. Take a short shakedown run and confirm no codes and no leaks.

Where a Chassis Cab Bites

Three places catch someone who’s done a pickup delete before and assumes it’s the same:

• The tune-first order. Removing hardware before the tune is in hand is the fastest way to a truck that derates the moment you key it on.
• The coolant line from under the block. Skip it and you’ve left a coolant path open (or a passage uncapped) that a pickup delete never exposed.
• The cut-to-fit exhaust. A pickup pipe bolts up; a chassis cab pipe has to be sized to your CA dimension, and getting it wrong means re-cutting or a pipe that doesn’t clear the frame.

The Legal Reality (Read Before You Commit)

Removing or tampering with emissions equipment on a road-registered vehicle violates the federal Clean Air Act (42 U.S.C. § 7522). Individual penalties can reach roughly $5,911 per violation under the statutory base — and recent EPA guidance has cited higher inflation-adjusted figures in commercial enforcement actions. Many chassis cabs face DOT visual inspections that pickups don’t, which raises the exposure on a commercial truck.

Conclusion

The whole point of this article is one sentence: the engine is the same, but the truck is not. A 6.7L Cummins in a 3500/4500/5500 cab & chassis needs a chassis-specific delete pipe, a C&C-aware tune, and a clear-eyed view of the Aisin transmission’s ceiling. Get any of those three wrong and you’ll be fighting fitment, fault codes, or a transmission that de-fuels under load.

If your chassis cab is a 2013–2019 3500/4500/5500, the Cab & Chassis DPF & EGR Delete Kit is built for exactly that truck. Match your model year off the door jamb, confirm your body style off the frame behind the cab, and the fitment question is already settled. At TruckTok, every kit is engineered for the exact platform it ships to — pickup or chassis cab — so you’re never adapting a pickup part to a commercial truck.

If you have any other questions, you can refer to the relevant blog：

• Why Your 6.7L Cummins DPF & EGR Delete Won’t Fit: Cab & Chassis vs Pickup
  
• 2013–2019 6.7L Cummins Cab & Chassis DPF & EGR Issues Explained
  
• 6.7L Ram Cummins Complete Delete: EGR Kit, Mid-Pipe, and Full 4" Exhaust
  
• Is Your 68RFE Transmission Filter Putting Your 6.7L Cummins at Risk?
  

Frequently Asked Questions

Does a 6.7L Cummins Cab & Chassis delete kit fit a standard Ram pickup? 

No. The chassis cab uses a different frame (C-channel vs tube-style), different fuel tank placement, and different exhaust routing, so a chassis-specific delete pipe will not line up on a pickup bed truck. The EGR block-off plates are shared because the engine is the same, but the DPF/exhaust pipe is chassis-specific and does not interchange.

Is the 6.7L Cummins engine itself different in a Cab & Chassis? 

The block, cylinder head, pistons, and crankshaft are the same as a pickup of the same generation. What differs is the aftertreatment routing, the injector and turbo calibration, and the transmission. The bottom end doesn’t care whether it’s in a pickup or a chassis cab.

Why does the chassis cab make less power than a pickup? 

It’s detuned from the factory for longevity. A 2019 chassis cab is rated 360 hp and 800 lb-ft versus 385 hp and 930 lb-ft on the 2018 pickup, because the chassis cab is meant to work hard and last. Ram trades peak output for service life on the commercial trucks.

Can I run a full-power delete tune on a Cab & Chassis? 

Generally no. The chassis cab runs the Aisin automatic, and its TCM has torque-limiting parameters that de-fuel the engine to protect the transmission. There’s no real software to unlock the C&C Aisin TCM, so the realistic ceiling is a tow tune around 50 hp. Push past that and the transmission fights you.

What does “pick up model only” on the instructions mean? 

It’s a note about the document, not the coverage. It tells you the photographs and step order were shot on a pickup, and it is not the record that decides whether the parts bolt to your engine. Read the fitment record for coverage and the instruction set for procedure.

Does a delete kit add horsepower? 

The delete itself doesn’t — the tune does. Removing the DPF and EGR removes restriction and failure points, but the power gain comes from the calibration you flash afterward. On a chassis cab, that tune is capped by the Aisin transmission, so don’t expect pickup-sized numbers.

Do I need a tuner for a Cab & Chassis delete? 

Yes, always. Removing emissions hardware without a supporting tune leaves the ECM throwing fault codes and likely entering a reduced-power mode. On 2018+ chassis cabs you also need a Security Gateway Module bypass cable before any flash.

Is the install different on a chassis cab? 

Yes, in a few concrete ways: the exhaust has to be cut to fit your cab-to-axle length, one EGR coolant line comes out from under the block rather than capping at the top, and 2018+ trucks need the security gateway bypass. The factory downpipe is also 4" with a flattened section worth replacing.

Is deleting a Cab & Chassis legal? 

Not on public roads. Removing emissions equipment on a road-registered vehicle violates the federal Clean Air Act, and many chassis cabs face DOT visual inspections that pickups don’t. These kits are for off-road, competition, and closed-course use only — check your local laws and duty cycle first.

What should I actually gain from deleting a chassis cab? 

Reliability, not horsepower. You eliminate regen cycles (which waste fuel and dilute oil), stop soot from caking the intake, and remove the EGR cooler as a failure point. On a truck that idles long and works hard, that’s the delete that pays for itself — but it’s capped around a 50 hp tow tune by the Aisin.