Wet Kit Installation on a Freightliner — Ames Hydraulics

Wet Kit Installation On A Freightliner — Cascadia, M2, 114SD, 122SD

We do wet kit installation on Freightliner trucks in our Ames, Iowa shop — Cascadia, M2 (medium duty), 114SD and 122SD vocational trucks, and the older Century Class. Freightliner is the most common truck we see for wet kits because they are common in the small-fleet and owner-operator market, and because a lot of Cascadias were spec’d without a wet kit and get retrofitted later when the owner picks up a hydraulic-powered trailer.

Every wet kit installation on a Freightliner is a full custom job — the truck’s transmission dictates the PTO, the trailer dictates the pump and line configuration, and the frame layout dictates the tank placement. We do the whole job in-house.

The Four Pieces

Every wet kit is four things: a PTO on the transmission, a pump driven by the PTO, a tank holding hydraulic fluid, and plumbing connecting everything to the trailer coupling. The PTO is where the drivetrain and the hydraulic system meet, so it has to match the transmission model exactly. The pump is sized to the trailer’s flow requirement. The tank is sized to the pump’s flow and the truck’s available real estate. The plumbing is either single-line, two-line, or three-line depending on the trailer’s pump type.

PTOs For A Freightliner

Cascadia and M2 units with Detroit DT12 automated manuals take Muncie AZ hot-shift PTOs specifically designed for the DT12. Older Cascadia with Eaton Fuller manuals use Chelsea 442 or 852 PTOs. Cascadia with Allison automatics — less common but seen on some vocational configurations — accept Chelsea 442-series hot-shift or Muncie CS8. 114SD and 122SD vocational trucks are often specced with Allison and take PTOs suited to the RDS transmission. Getting the PTO right is the linchpin — a wrong PTO can’t be corrected without pulling the pump and reworking the drive.

The DT12 automated manual specifically requires attention because early DT12s had known PTO integration issues that were revised in the 2019+ model year. If your Cascadia is 2016-2018 with a DT12 there are things to verify before we spec the PTO.

Line Configuration And Pump

Two-line wet kits are what most Freightliner owners need — they cover walking-floor, live-bottom, and mid-size dump trailer work. Single-line is enough for a light end-dump only. Three-line with case drain is required for piston-pump trailers and larger hydraulic-motor applications. The pump itself is sized for the trailer: gear pump (Parker/Chelsea) for gear-pump trailers, piston pump (Parker P30/P50) for piston-pump trailers.

A wet kit installation on a Freightliner that’s built to only run one trailer type is straightforward. Ones built to run multiple trailer types are trickier — we spec for the highest-flow trailer and the pump has enough headroom for lighter trailers too. That’s a slightly more expensive install but the truck stays flexible.

Tank Sizing On A Cascadia Aero Cab

The Cascadia aero cab is a challenge for tank placement because there is not much clearance behind the sleeper. We usually frame-mount a 40-50 gallon tank on the passenger side rail or use a lower-profile tank behind the cab if the truck has a day cab configuration. On M2 medium duty the frame layout is much friendlier and we can go 50-60 gallons if the trailer type needs it. On 114SD and 122SD vocational trucks there’s plenty of tank space and we often use larger tanks for continuous-duty applications.

Common Wet Kit Retrofit Problems On A Freightliner

The most common wet kit installation on a Freightliner is actually a retrofit — someone else did the original install and it wasn’t right. Common issues: pump under-sized for the trailer, PTO turning wrong direction, tank too small, return line routed wrong causing overheating, ground straps not right on the electrical side of the PTO shift. We see 3-4 of these retrofits a month. We tear out the wrong parts, correct the spec, and rebuild it right.

Cost And Turnaround

Basic single-line wet kit installation on a Freightliner is $2,800-$4,500. Two-line is $4,500-$7,000. Three-line piston-pump installs are $6,500-$8,500. Retrofits that require tearing out a bad prior install add $500-2,000 depending on what needs to be redone. Turnaround is one to two weeks. Written quote before we start work.

Independent Scope

We are not a Freightliner dealer. We do not do Detroit engine work, DEF/emissions repairs, or warranty items. If your Freightliner is under warranty, DTNA (Detroit Diesel/Freightliner) dealers are the right stop for warranty work. Out-of-warranty hydraulic, wet kit, dump hoist, and frame welding is what we do.

Common Questions About A Wet Kit Installation On A Freightliner

How long does a wet kit installation on a Freightliner take? One to two weeks depending on parts availability and shop load. Cascadia and M2 installs are straightforward once we have the right PTO in hand; retrofits take longer if there’s a bad prior install to remove.

Will a wet kit installation on a Freightliner void my warranty? Out-of-warranty trucks, no concern. On trucks still under DTNA warranty, adding a PTO can potentially affect transmission warranty — check with the dealer if you’re within your warranty period.

Do you install wet kits on the DT12 Cascadia? Yes. Early DT12 installs required specific PTO parts that were updated in 2019+. We spec after we verify the transmission year and revision.

What if my Freightliner already has a bad wet kit? Retrofit wet kit installation on a Freightliner is common — we tear out the wrong parts, correct the spec, and rebuild. Adds $500-2,000 depending on scope.

Get A Quote

Call or text 515-292-2599 with the model, year, transmission, and the trailer you plan to pull. We’ll ballpark the wet kit installation on a Freightliner on the phone and firm the quote when we see the truck.