Stiff cranking, a leaning trailer, or a leg that won't retract are signs your trailer landing gear needs repair. Here's how to spot trouble early and what causes it.
By Vladimir Sardari · Owner & Lead Technician 
Trailer landing gear needs repair when the crank becomes hard to turn, the legs no longer raise or lower evenly, the gearbox grinds or slips, or a leg shows visible bending, cracks, or a broken foot pad. Catch these symptoms early and you usually face a gearbox or leg-section fix; ignore them and you risk a trailer dropping in the yard, a damaged kingpin, or an unsafe coupling. Below is how to read the signs, what causes them, and how the repair is approached.
Landing gear (also called trailer legs or dollies) is the two-legged support that holds the front of a semi-trailer level when it's uncoupled from the tractor. A hand crank drives a gearbox, which turns internal screws inside each leg to raise and lower the trailer. A low gear gives you the mechanical advantage to lift a loaded trailer; a high gear lets you spin the legs up or down quickly once the weight is off them.
Because the gear sits low on the trailer and gets cranked thousands of times over its life, it wears and takes abuse. The most common reasons it fails:
The Federal Motor Carrier Safety Administration's cargo securement and vehicle inspection rules treat the trailer's support and coupling system as safety-critical, so worn landing gear isn't just an inconvenience. A leg that collapses under a loaded trailer can injure people and damage the trailer structure.
Most landing gear problems announce themselves at the crank handle or in how the trailer sits. Watch for these.
If the handle suddenly takes far more effort than usual, the internal screw is likely dry, contaminated, or starting to corrode. A gritty or notchy feel as you turn often means worn bevel gears or debris in the gearbox. Don't force it with a cheater bar; that's how teeth get stripped and shafts get bent.
Landing gear legs are linked by a cross shaft so both rise and lower together. If the trailer leans to one side, the cross shaft, a coupling pin, or one leg's internal screw has failed and the legs are no longer synchronized. A leaning trailer puts uneven load on the kingpin and fifth wheel.
A grinding noise points to metal-on-metal contact from missing grease or chipped teeth. If the crank spins freely without raising the trailer, the gear teeth or the pinion have stripped and the gearbox is no longer transmitting force.
A leg stuck partway up is a roadworthiness problem and a coupling hazard. Causes include a seized screw, a bent inner leg, or internal corrosion. A leg that won't extend fully can leave the trailer unstable when you drop it.
Any of these calls for inspection before the trailer is dropped again.
The right fix depends on what failed and how far the damage has spread.
If the legs still operate but cranking is stiff, the first step is cleaning and re-greasing the gearbox, cross shaft, and internal screws. Catching a dry gearbox early is the cheapest outcome and often restores smooth operation.
When the gearbox grinds, slips, or free-spins, the internal bevel gears and pinion are usually worn or stripped. Many landing gear designs allow the gearbox to be rebuilt or swapped without replacing the whole leg assembly. A bent cross shaft or sheared coupling pin is also a contained repair.
Bent leg tubes, cracked mounting welds, or a seized, corroded internal screw usually mean replacing the affected leg or the complete two-leg assembly. Cracked welds at the frame are structural and should be repaired by a technician, not patched in the field. Both legs are typically serviced together so they stay synchronized and wear evenly.
This kind of work overlaps with broader trailer repair, since landing gear problems often surface alongside suspension, wiring, or air-system issues during the same inspection.
You can't stop every impact, but routine care prevents most failures:
Drivers and dispatchers running the I-5, I-80, CA-99, and US-50 corridors around Sacramento see plenty of salt and grit kicked up in winter, which accelerates corrosion inside neglected gearboxes. A quick grease and inspection between loads is far cheaper than a roadside leg failure.
You can move a trailer with the legs fully retracted and locked, but you should not drop or park it on a leg that's bent, cracked, or won't extend fully. A failed support can let the trailer drop, damaging the trailer and creating a safety hazard. Have it inspected before the next uncoupling.
The most common cause is a dry or contaminated gearbox and screw assembly. Dirt, water, and road salt work in past worn seals and the internal threads bind. Worn bevel gears can also create a notchy, hard-to-turn feel. Cleaning and re-greasing fixes many cases, but grinding or slipping usually means internal wear that needs repair.
When a leg assembly is worn or damaged, technicians often service or replace both legs together. The legs are linked by a cross shaft and need to operate in sync; matching their condition keeps the trailer level and prevents the good leg from carrying uneven load.
It can be. If the trailer leans while parked on its legs, one leg may be lagging because of a failed internal screw, a bent leg, or a broken cross shaft pin. It's worth inspecting promptly, since uneven support stresses the kingpin and fifth wheel.
If your landing gear is stiff, grinding, leaning, or won't fully raise, don't wait for it to drop a trailer. 916 Truck Repair offers mobile, on-site service across the Sacramento metro and Northern California. Call (916) 898-9090 for 24/7 dispatch.
Mobile truck repair for highway breakdowns, truck stops, fleet yards, docks, and roadside service calls.
Call (916) 898-9090