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Under-floor electric slides: tell the designs apart

Every electric under-floor room rides on rails through the frame, but it's pushed one of two ways: a ball-screw actuator with a clutch, or a brake motor turning pinions on gear racks. Name the one you're under before you test anything, because the override, the stops and the failures are different.

The short version

Two ways to push a room through the frame

Every system in this course hangs the room on inner tubes (Power Gear calls them inner rails) that slide inside outer tubes running through the main frame rails. The inner rails carry the weight of the room. What changes from one system to the next is what does the pushing.

On Lippert's Electric Through Frame with actuator, a motor turns a ball screw inside an actuator, and the screw shoves the room in and out. The actuator has an automatic clutching system so the motor can stop against the end of travel. Gear racks and gear packs are still there, but Lippert calls them the guide system: they keep the tubes even while the actuator does the work.

On a rack-and-pinion drive, a 12 V DC gearmotor turns a shaft that runs across to a spur gear (the pinion) on each rail, and those gears walk the gear racks in the inner rails. There's no actuator and no clutch. A brake on the motor holds the room when the motor stops, and Power Gear's control senses the load and shuts the motor off at full in and full out.

Which product name goes with which design

Here's the trap. In Lippert's own documents, Power Gear electric is the brake-motor rack and pinion, not the ball screw. The ball screw with the clutch and the stop can is Lippert's own Electric Through Frame. Lippert owns and supports both now, so the name on the invoice doesn't settle it. What's bolted under the coach does.

This course covers the first three rows in depth. If you find a synchronized control with encoder harnesses, pull that system's own manual for faults and initialization before you touch anything mechanical.

Name on the manualDriveWhat stops and holds the roomDocument
Lippert Electric Through Frame with actuator (2x2, 2.5x2.5)Ball-screw actuator, Tuson or Venture, 18:1 to 58:1Automatic clutch in the actuator; stop can and nuts on the actuator shaftCCD-0001613; Electric Slideout System manual rev B
Lippert Electric Through Frame center drive, plus the motor-driven 2x3 and 3x3 pivot railGearmotor (Klauber M-150N, D-300 and others) turning gear packs on the racks, with a cross shaftCovered in the center drive manualCCD-0001613 parts pages; CCD-0010725
Power Gear electric slide-out, sold by Lippert as the Electric Motor Slide-out12 V DC gearmotor with brake, square drive shaft to spur gears on both railsMotor brake with a hand release lever; control stops the motor on load at full travelCCD-0001615 (from Power Gear 82-S0380); Power Gear service manual
Power Gear E-Sync and M2-SyncMotors kept together electronicallyProgrammable control with encodersTheir own manuals and encoder tests on support.lci1.com

What each one looks like under the coach

Get under the room with a light before you run the switch. Thirty seconds of looking tells you which manual to pull and which override you'll be using if it comes to that.

Cross shafts don't settle it

Lippert's actuator owner's manual has you check cross shaft clearance and gear pack function, so a cross shaft between the gear packs doesn't make it a motor drive. Look for the actuator tube. Lippert's rev B service manual also describes an active tube (the one the actuator drives) and a passive tube with a synchronizing bracket for evening the sides.

Lippert's hydraulic through-frame uses the same family of tubes, heads and gear packs with a cylinder doing the pushing. The tube adjustments look familiar, but the diagnosis is hydraulic and belongs in a different course.

Rack systems that aren't in this course

SlimRack and SlimRack Plus are rack and pinion too, but the motors sit at the top of vertical channels in the wall opening, above the floor. Lippert's Above Floor system uses hat channel and a drive box on the room floor. Neither runs tubes through the frame, and each has its own manual and override steps.

Read the labels before you order

Lippert's listing for a replacement actuator says to take the specs off the current motor label and order to match. Actuators come in different lengths and ratios, and Lippert publishes an identification sheet (TI-008, also QR-186) to tell Toula, Venture and Tuson units apart. Lippert also asks for the power unit's serial number and date code when you call.

Gear packs are sized to the tube, and the pinions come in two tooth forms: an 18-tooth 14.5 degree gear and a 15-tooth 20 degree gear. TI-001 shows how to tell them apart. On Power Gear, the gearmotor part number and the Gear ID chart (82-S0507) do the same job.

On the job

  1. Look under the room from both sides of the coach before you touch the switch.
  2. Find the drive: a long actuator with a stop can on its shaft, or a gearmotor with a booted brake lever and a square shaft.
  3. Photograph the actuator or motor label: part number, ratio, length, serial number and date code.
  4. Note the tube size and whether a cross shaft runs between the gear packs.
  5. Look for a control box: Power Gear relay, current limiter or sync control, or just a wall switch.
  6. Pull the matching manual from support.lci1.com before you start testing.

Numbers

Shop tip

Take a phone picture of the motor or actuator label before you crawl back out. Lippert's own parts listing says to order from that label, and you won't want to go back under for it.

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