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JAN 13, 2026

How to Operate the Thieman LRST-40 Liftgate: Complete Step-By-Step Guide

The Thieman LRST-40 is a self-leveling, level-ride stowaway lift designed to move cargo safely between the truck bed and the ground.

This guide walks operators through the complete manual-approved operating sequence and the key safety practices needed to run this tuck under liftgate correctly every day.

Using the correct procedure helps protect your crew, your equipment, and your freight while preserving the performance of your OEM liftgate parts.

• Documentation Resources from Thieman
• Safety Requirements Before Operating
• Step-By-Step Operation Procedure
• Understanding Duty Cycle and Pump Thermal Limits
• Load Handling and Positioning Protocols During Operation
• Common Operator Errors and Why They Are Unsafe
• Conclusion

Documentation Resources from Thieman

Information in this article is sourced from Thieman LRST-40 manuals and technical guides as well as our team’s expertise. Always refer to your specific liftgate’s manuals for complete procedures and serial number, model, and year-specific details.

Reference PDFs used:

• Thieman LRST-40 Owners Manual
• Thieman LRST-40 Installation Manual
• Thieman LRST-40 Brochure

Safety Requirements Before Operating

Before touching the control switch, operators must confirm that the vehicle, the liftgate, and the surrounding area are safe for use. The Thieman LRST-40 Owner’s Manual dedicates multiple pages to safety warnings that must be followed on every cycle.

Critical Warnings from the Owner’s Manual

Key safety requirements include:

• The vehicle must be securely and properly braked on level ground before using the liftgate.
• All protective covers and guards must be in place before operating.
• The gate is not a personnel lift; riding the platform is prohibited and can lead to severe injury or death.
• Operators must be properly instructed and must read and understand the Owner’s Manual and decals before using the lift.
• Only authorized Thieman distributors are qualified to repair the liftgate; unapproved repairs or modifications can void warranties and create hazards.

The manual also stresses that all operators must be at least 18 years old and that everyone must stay clear of the liftgate when it is in motion.

Surrounding Hazards

The LRST-40 is designed for cargo transfer strictly between the truck bed and the ground surface on which the vehicle is parked. Operators must:

• Avoid using the liftgate to load or unload from elevated surfaces such as docks, sidewalks, or raised slabs. Suspension squat and partial support can create unstable conditions and damage the liftgate.
• Verify the area above, below, and around the platform and lift arms is clear before and during operation.
• Keep bystanders away from zones where a falling load could land.

Taking a moment to confirm these pre-operation safety requirements dramatically reduces risk. Every LRST-40 cycle should begin with a quick visual inspection, a check of the surroundings, and adherence to the Owner’s Manual warnings.

Step-By-Step Operation Procedure

Thieman organizes the LRST-40 operation into four phases: UNLATCH, UNFOLD, RAISE/LOWER, and STORE FOR TRANSIT. The steps below follow the manual’s sequence exactly, with verbal descriptions of the associated diagrams.

Phase 1: UNLATCH

From the fully stowed position on this tuckaway liftgate, the goal of the unlatch phase is to release the platform from the spacer latches so it can be deployed.

• Use the switch to raise the liftgate (UP) until the stow pins are tight against the nylon pads on the spacer.
• Push the spacer handle down with your fingertips to disengage the spacer latches and keep it held down.
• While holding the spacer handle, press DOWN to slightly lower the liftgate until the stow pins clear the spacer latches, then release the handle.

Verbal diagram: picture the stow pins as two horizontal pins that tuck into latches on the spacer. Raising the gate seats them; pulling the handle releases them so the lift can swing away from the spacer.

Phase 2: UNFOLD

After unlatching, the platform is lowered and unfolded into working position.

• Continue lowering by pressing DOWN until the lift arms make contact with the ground.
• Use the curb-side platform handle to rotate the main platform section outward to a horizontal position.
• Unfold the platform extension (ramp) until it is horizontal with the main platform.

The diagrams in the Owner’s Manual show this as a two-stage opening: first the main platform swings out, then the ramp extends to form the full 80" x 60" load surface.

Phase 3: RAISE / LOWER

The LRST-40 uses a self-leveling motion to keep the platform stable as it transitions between ground and bed height.

• To raise the platform, press UP. The lift arms will pivot so the platform first levels itself, then lifts off the ground as a single, stable surface.
• To lower the platform, press DOWN. Once the arms rest on the ground, continue holding DOWN until the nose of the platform tilts downward and the ramp tip contacts the ground.

Verbal diagram: lowering occurs in two stages—arms down to the ground, then the nose tilts forward into a gentle ramp. Raising reverses this: the nose comes up and the platform levels before it starts to lift toward bed height.

Phase 4: STORE FOR TRANSIT

Properly stowing this tuck-under liftgate is essential to prevent damage and road hazards.

• With the arms on the ground and the platform horizontal (nose slightly off the ground), fold the platform extension over on top of the main platform.
• Lift from the underside of the folded platform and rotate it upward. Use the curb-side handle to guide the platform in until it rests against the nylon kicker roller.
• Press UP to raise the liftgate into the stowed position.
• Continue raising until the stow pins on both sides are tight against the spacer’s nylon pads and fully engaged in the latches. Do not leave the stow pins partially engaged.

Following this four-phase sequence ensures that the LRST-40 operates the way Thieman Tailgates intended: stable, predictable, and safe. Operators should practice the sequence slowly at first, paying close attention to the platform motion and the stow pins.

Understanding Duty Cycle and Pump Thermal Limits

The LRST-40 hydraulic pump and motor are designed for intermittent use. The Owner’s Manual specifies strict duty-cycle limits to prevent overheating, especially when handling heavier freight.

Thermal and Duty-Cycle Limits

The manual’s thermal data states:

• Do not operate the unit for more than 5 cycles per 10 minutes with the maximum load.
• After running 5 cycles in 10 minutes at maximum load, the motor must be allowed to cool down completely to ambient temperature before cycling the lift again.
• The system has a 10% duty cycle, meaning the liftgate can be cycled no more than 2 cycles per 10 minutes continuously with the maximum load.

Exceeding these limits can overheat the motor, gear pump, motor start solenoid, and valve coils, and may cause immediate component damage in severe cases.

Operators should track how frequently the lift is cycled—especially during back-to-back stops. Adhering to the 5-cycles/10-minute and 10% duty cycle rules keeps the hydraulic power unit within its thermal design range and extends the life of critical liftgate parts.

Load Handling and Positioning Protocols During Operation

Even when the mechanical system is functioning correctly, poor load placement can overload the LRST-40 or cause sudden shifts. The Owner’s Manual provides clear guidance on how to position freight safely on the platform.

Proper Load Placement

Thieman specifies that:

• The center of weight of the load must never be placed beyond the center of the platform’s load surface away from the truck.
• Loads should be placed close to the platform edge nearest the truck; if the load is not uniform, the heaviest portion should be nearest the truck.
• No part of the load should extend beyond the edges of the platform’s flat load surface.
• When loading or unloading at ground level, loading must be done from the rear of the platform—not from the left or right side.

These rules help keep the platform level and reduce the chance of a nose-down tilt while lowering. The manual specifically warns that on the LRST model, off-center loading away from the truck can cause the platform nose to tilt downward severely as it is lowered from bed level. Operators must stop lowering the liftgate immediately and re-center the load if this occurs.

Unstable or Unsafe Loads

Additional operator responsibilities include:

• Never lifting or lowering unstable loads.
• Not attempting to grab or restrain a load that is tipping, falling, or rolling off the platform.
• Ensuring the platform load surface is not slippery before stepping onto it or placing freight.

Consistent, correct load placement is one of the most effective ways to avoid incidents on any tuck-under liftgate. Training operators to recognize and correct off-center or overhanging loads will help prevent damage and downtime.

Common Operator Errors and Why They Are Unsafe

The LRST-40 warnings list several misuse scenarios that significantly increase risk. Understanding why they are unsafe helps operators break bad habits and avoid repeat issues.

Loading From the Side

The manual clearly states that loading and unloading at ground level must be performed from the rear, not from the left or right sides of the platform. Side loading can off-center the load and overload the lift structure, increasing the chance of tipping or sudden movement.

Riding the Platform

Because of pinch points, fall hazards, and the potential for sudden drops or tilts, the LRST-40 is not a personnel lift. Riding the platform puts operators in the path of moving components and unstable freight and is expressly prohibited.

Failing to Confirm Stow Pins

If the stow pins are not fully engaged in the spacer latches before transit, the platform can move unexpectedly and create a serious traffic hazard. The manual instructs operators to ensure the pins are powered tight against the spacer and captured by the latches at the end of the stow sequence.

Operating at Elevated Surfaces

Using the LRST-40 at a raised dock or similar surface can change the effective bed height and leave only part of the platform supported. The manual warns that this can overload components and “may lead to a sudden liftgate failure.”

These common errors—side loading, riding the platform, skipping stow checks, and working from raised surfaces—directly contradict the Owner’s Manual. Eliminating them is critical to safe, reliable LRST-40 operation.

Conclusion

The Thieman LRST-40 is a durable, self-leveling tuck-away liftgate that can deliver long, reliable service when operators follow the documented procedures. Running through the four operation phases correctly, positioning loads within the platform footprint, and respecting thermal duty-cycle limits all contribute to safe, consistent performance.

When you need replacement tuck under liftgate parts or have questions about the safe operation of your Thieman LRST-40 liftgate, contact our team at LiftGateMe. We can help you source the right OEM liftgate parts and ensure your LRST-40 stays in service and operating as intended by Thieman Tailgates.