Freightliner Custom Chassis provides New SL-M Chassis to the RV Industry for 2013

The Freightliner Custom Chassis Exhibit at the RVIA Exposition Unveiled New Technologies  



The Detroit Diesel DD-13

A specialty oil pan is fitted that is wider than the engine which allows the engine to sit deeper in the rail reducing the intrusion inside the cabin.  With the engine sitting lower,  driveline components are as straight as possible and angles are reduced to minimums.

Not too much later, Tony Sippel came by to say hello as well.  Tony was recently promoted to Director of Sales and Marketing and I offered him congratulations on his October 2012 promotion.  Tony has been with Freightliner for many years and was previously the RV Product Manager.  In my previous report from Gaffney, Tony and I toured the entire facility and he showed me how the RV chassis products are produced and how they progress down the assembly line from joining the rails to testing the chassis on dynos.  At that time FCCC has just introduced the XC Tag axle chassis.  At the end of the tour, I was able to see one the initial build units that was shipping out to the West FMCA Convention.


The belt routing is shown on the DD-13 showing a number if idlers and belt tensioner. Seen are air compressor, air conditioning compressor, alternator and power steering pump.

Tony offered that FCCC was enthusiastic about information technology and that the company was investing time and energy in developing and bringing out new iPad apps.   Tony said that in time, customers are going to have access to customer focused apps that will improve their ownership experience by having readily available information on their mobile devices.   In our conversation, I had a question about a suspension setup.  Tony walked me over to a kiosk which had an iPad sitting on top of the display.   The kiosk also had a large LCD panel above where the image on the iPad was replicated. Tony remarked that just about every feature of the Freightliner RV product line was contained in the SalesHQ app.  He pointed to a link on the screen and this triggered a print out of the specs that we were talking about.  The SalesHQ app shown at RVIA will not be available to the general public as the app was designed for OEMs and dealers sales staff.

The DD13’s output side showing its flywheel.  On the right side of the engine top, is the EGR cooler and mid way is the VGT turbo charger.  Seen is the massive cylinder head on the DD-13 and fuel lines. The large diameter pipe in the foreground, routes the hot exhaust gases from the engine to the “One-Box”.  Additional shielding is seen directly below the exhaust pipe to protect transmission lines.

The FCCC Customer Service department is working towards producing operation and maintenance videos for customer use. Distribution of this library of information is being developed and it is expected that in time it will be available on mobile devices.   I also mentioned to Tony that  brief webinars from Mike Cody who is the Gaffney, SC based Camp Freightliner lead instructor would also be useful.    iRV2 Freightliner owners have for the past several months logged into the iRV2 chat rooms and have had held sessions on Wednesday evenings from  9:00pm to 10:00pm Eastern.   Information of all types is exchanged during these sessions.   All are welcome to attend.

The DEF tank is attached to the frame rail and is always identified with a blue filler cap. The fluid in this tank is supplied to a doser valve in between the DPF and the SCR. Liquid urea combines with the gasses from the DPF which helps the SCR to completely process the NOx down to water vapor and Nitrogen.

Shown forward of the “One-Box” is the electrical compartment on the SL-M which holds the automotive batteries and power disconnect switches. (right center)

What is described as an SL-M chassis for all intents and purposes looks like a raised rail chassis.  SL-M is intended to be modular and from what I understand the back of the chassis is one component, the mid-rail is another and the front suspension is attached to a 3rd component.  When approaching the front of the SL-M one can see the robust dimension of the chassis rail.  On the display model, the IFS steering components which use un-equal length wishbone type A frames are connected to the frame inboard and the steering knuckles outboard.  Large diameter inboard air bags provide the ride quality that is built into each Freightliner.  Tuned Sachs shock absorbers dampen the ride and smooth out the road.  The ZF IFS suspension provides 60° of wheel cut making it one of the most maneuverable RV chassis in the industry.  One can also see where all the supporting equipment is specifically manufactured per OEM specifications and wrapped in coils waiting for assembly.  As seen, the rails comprise the foundation for the house.  What is even more fascinating to witness is when the sub framing is completed right before the box goes on.   Looking very much like an erector set the subfloor is engineered to contain all the support systems, tanks, storage compartments of the RV.  From one corner to the next the subfloor is critically assembled and trued within fractions of an inch.


In the midsection of the vehicle you would see where the fuel tank is located along with air tanks, dryers, several air valves and assorted plumbing including several lengths of bundled air and fuel hoses and electrical bundles and modular connectors.  Most all the electrical and critical lines are wrapped in wire loom and tie wrapped.  Frame members are bolted together using dozens of fasteners which speak to unequalled frame integrity and rigidity.  The area immediately below the center of the rail is clear and provides the OEM an uncluttered enormous space in which to create large pass through storage spaces.    The exhibit chassis that was shown had extra length of hoses and lines that were seen drooping under the center of the chassis however this is how the OEM ordered this particular rail.   With extra lengths of support plumbing and wiring fitted to the chassis it becomes easier for OEMs to adjust the wheelbase of the vehicle and the floor plan configuration depending on the specific length of the coach they are building.  Re-sectioning the frame can be accomplished by removing and replacing the center frame sections with longer rails.  This I expect is one of the biggest selling points for the SL- “Modular” chassis.  It is not unusual to see the SL-M used on 42 foot (+) long motorhomes.


The SL-M shown features an IFS front suspension and a 60° wheel cut for hi-maneuverability. The SL-M per the OEMs request is shipped with several feet of extra length hose for the various systems on the chassis. The extra house is routed in the subfloor and body to locations where it is needed.   The front axle sits on 315/80 XZA and gives this machine an awesome look. The GVWR on the chassis goes up to 54,000 & GCWR is 64,000 pounds.

The rear of the chassis contains the entire powertrain to include the engine, transmission, differentials and drive shafts.   The rear suspension of the SL is a Holland Neway design which provides a fully integrated system with unequalled ride and handling. Freightliner’s industry first auto load sensor provides automatic load proportioning across all 3 axles for a smooth well balanced ride.  The massive 500HP – 1650 lb-ft of torque 13L Detroit diesel engine is impressive and takes up most of the space in between the frame rails. The DD-13 integrates a 3 stage, Jacobs engine brake, which assures excellent forward speed control by means of engine compression and gearing when lifting off the throttle.   As seen, the exhibit model had a side cool pack configuration however this chassis can be provided with a rear cool pack as well.  The DD13 is coupled to an Allison 4000MH automatic transmission.   Freightliner Custom Chassis is in the process of also developing engines up to 600 HP for RV applications and it is expected that this product will begin shipping shortly.


Looking forward at the A frames on the IFS suspension and the ping tanks mounted over the front axle. Sachs shocks provide rebound control on the SL-M The yellow block on the top of the chassis is shipped in this position to add weight to the front of the suspension so that it can be steered when unladed. The steel yellow block is removed and returned to Gaffney to be installed on a follow-up chassis.

The DD13 also features a “Virtual Technician.” (VT)  The VT is a factory installed system which is an on-board diagnostic tool.  So equipped and in the event a DTC is issued both Detroit Customer Support and the driver are informed of the anomaly by reviewing pre-event, during and post event conditions that triggered the fault code.  The immediate benefit of the VT is that the owner would be immediately notified if the condition requires the owner to pull over for service or continue with their travels.  Service arrangements would be made where parts are available, enroute, at your point of arrival or wherever a service location is conveniently available.   The system is GPS driven.  When the DCT is issued, the IP will trigger a GPS transmission that would send a data stream to the service technicians.  Once received, a solution would be sent back to the customer via email or cell phone notifying the driver and the service center of the issue.


The engine is complete on this chassis and this vehicle was driven onto the display. The SCR and DPF are contained inside of heat shielding which become necessary with the 500HP engine.  Shown is the tag axle and drive axle on the SL-M (S Series; Luxury; Modular)  One can also observe how low the engine sits inside the rail in this side view.

All Freightliner Custom Chassis vehicles are currently in compliance with GHG14 emission requirements according to a company press release.  Fitted to the DD13 is an emission control package called One-Box.  The One-Box is located curb-side aft of the engine.  The One-Box is a thermally shielded enclosure that contains all the emission control systems to include the DPF, DOC, doser valves and SCR.   The SCR system provides an after treatment path using diesel exhaust fluid injected into the exhaust stream where filters and catalysts process the exhausted gasses.  The end result that comes from the tail pipe are the environmentally friendly gasses, Nitrogen and water vapor.

Cummins ISB power is applied to an Allison 2500MH transmission on this XC-S chassis.  Shown is the DPF on top and the SCR on the bottom. In between these two devices is a doser valve which feeds the urea from the tank to the SCR bottom.

Typical GCWR for XC-S chassis may range from 26.850 to 47,000 pounds with tag axle and may be powered by Cummins ISB, ISC or the ISL engines.



About Mike Pelchat

In January 2000, Mike assisted in forming the iRV2 Nor’easters Regional Group and by September of 2001, the 1st National Rally was held at the Ocean Lakes Campground in Myrtle Beach, SC. As an iRV2 member; Mike has served as a Moderator, Administrator and is currently the Marketing Director for Mike writes photo essays which range from RV Industry News, product reviews, component installations, travel and general interest topics.

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