Wet Kit Installation on a Kenworth — Ames Hydraulics

Wet Kit Installation On A Kenworth — Real Shop, Real Answers

A wet kit installation on a Kenworth is a mechanical job with a spec sheet, not a mystery. We install wet kits on Kenworth T680, T880, W900, T800, and older T660 trucks at our Ames, Iowa shop. Every install is sized to the trailer that truck is actually going to pull — because a wet kit built for a light dump does not run a walking floor, and one built for a walking floor is overkill on a light-duty dumper.

Kenworth shares the PACCAR MX drivetrain with Peterbilt, and most of what applies to a Peterbilt install applies here. What’s different is the frame layout, the cab-to-fifth-wheel distance, and where the tank ends up. On a Kenworth T680 or T880 aero cab the tank usually goes on the frame rail because there is very little clearance behind the sleeper. On a W900 the classic long hood gives us room to work.

What A Wet Kit Actually Is

A wet kit installation on a Kenworth adds four components to the truck. The PTO mounts to the transmission and creates a rotating output. The pump is driven by the PTO and generates hydraulic pressure. The tank holds the hydraulic fluid, feeds the pump, and receives return oil. The plumbing connects everything together and runs to the trailer coupling on the frame rail. Once these four pieces are installed and pressure-tested, you can hook up any hydraulic-powered trailer and drive it.

Line Configurations

Single-line wet kits are the simplest — one pressure hose from the truck to the trailer, gravity or a return valve routes fluid back. This works for light end-dump trailers that only need occasional lifts. Two-line wet kits use both pressure and return lines and are the most common install we do on a Kenworth, because they run walking-floor, live-bottom, and mid-size dump trailers. Three-line adds a case drain and is required when the trailer’s pump or motor is a piston type that needs continuous drain circulation. Grain live-bottom trailers and larger blower trailers usually need three-line.

Pick the wrong line configuration and the truck can’t do the job. Pick the wrong pump inside that configuration and the truck can do the job but slowly or hot. We spec both after we know exactly what trailer is being pulled.

PTOs For A Kenworth Transmission

Kenworth trucks with Eaton Fuller manual transmissions (10-speed, 13-speed) accept Chelsea 442, Chelsea 852, or Muncie CS8 PTOs depending on the housing. Newer PACCAR TX-12 and TX-18 automated manuals in T680 and T880 configurations use Muncie AZ or Parker Chelsea PTOs sized to the case. Allison automatics — less common on Kenworth road trucks but sometimes seen on vocational T880 units — take a hot-shift Muncie or Chelsea unit that can be engaged in-cab. The PTO must match the trans model, and the pump input shaft must match the PTO output. Getting one link wrong burns a week waiting on the correct part.

Pump Selection For The Trailer You Pull

For a light end-dump trailer, a Chelsea C102 or C102-series gear pump is enough. For a walking floor a Parker 3000-series gear pump at higher displacement works well. For a live-bottom or a large blower trailer a piston pump — Parker P30 or P50 — is required, and that’s where the three-line install comes in. We spec the pump based on the trailer’s flow requirement, not on what’s cheap. An undersized pump is the number-one wet kit failure we retrofit.

Tank Sizing On A Kenworth

The tank has to hold enough oil to keep the pump fed even at max flow, and it has to give returning oil enough time to cool before it recirculates. Light end-dump work runs on 30 gallons. Walking floor and live-bottom usually need 45 to 60 gallons. Blower trailers with high continuous flow can push 60 gallons plus. On a Kenworth T680 aero cab we frame-mount 40-50 gallon rectangular tanks; on a W900 long hood we can go bigger. All tanks have baffled internal walls, filler-breather, sight gauge, and correctly-oriented suction and return ports.

Turnaround And Cost For Wet Kit Installation On A Kenworth

Basic single-line install: $2,800-$4,500. Two-line: $4,500-$7,000. Three-line piston-pump install for live-bottom or blower: $6,500-$8,500. Add $500-1,500 for a custom-built tank if the truck needs a non-standard size or mounting. Turnaround is one to two weeks depending on parts and shop load. Written quote before work starts.

What We Don’t Do

Wet kit installation on a Kenworth from our shop means the hydraulic side. We are not a Kenworth dealer. We do not do PACCAR engine work, ECU programming, or warranty repairs. If your truck is under warranty, go to the dealer network for warranty items. Out-of-warranty hydraulic and structural work is our specialty.

Common Questions About A Wet Kit Installation On A Kenworth

How long does the install take? A wet kit installation on a Kenworth takes one to two weeks from drop-off to ready, depending on which parts we need to order and how loaded the shop is. Simple single-line dump-trailer installs can occasionally be turned in five business days.

Do you install on my truck if I supply the PTO and pump? Yes, but we still verify the spec before we start. If the PTO doesn’t match the transmission or the pump is wrong for the trailer, we’ll tell you before we hang parts.

Will the wet kit installation on a Kenworth affect my warranty? On out-of-warranty trucks, no. On trucks still under PACCAR warranty, adding a PTO can have implications on the transmission warranty — check with PACCAR before you commit if that matters to you.

Can you retrofit a bad prior install? Yes. Retrofit wet kit installation on a Kenworth is common — someone else did it wrong, we tear out the bad parts and rebuild it right. Adds $500-2,000 to a fresh-install price.

Get A Quote

Call or text 515-292-2599. Tell us the Kenworth model, transmission, and what trailer you plan to pull. We’ll ballpark the wet kit installation on a Kenworth over the phone and firm it up when we see the truck.