If you gotta be stuck hanging out on a hot porch in the middle of nowhere waiting for UPS to show up with parts you need for an RV repair, there is no better place than the Stillwell Store. But more about that later.
This post is intended for anyone who wants to save the expense of a trip to the RV shop after discovering their landing gear (AKA: Front Legs, Leveling Jacks, Etc.) may be malfunctioning. Specifically, I shall address how to replace the gearbox on the DC motor that powers the landing gear on our Arctic Fox 24-5N fifth wheel trailer.
Diagnose the Problem
Puuurrrrrrrrrrrrr, chunk, chunk, purrrrrrr, chunk, purrrrrrrr, chunk, chunk! Chunk-k-k…
Don’t let your gearbox get that bad. The first time you hear something like this when extending the legs on your fifth wheel when unhitching, or hitching up, investigate further, immediately. Upon hearing such a noise, watch the motor as you extend the legs. If the motor assembly dances about in tune with the chunkity chunk chunk, the gearbox is probably going bad. The good news is, the gearbox can be replaced without having to replace the motor.
Find the Right Parts
Northwood Manufacturing has always been very helpful in answering technical questions and troubleshooting any issues we have had with our Arctic Fox, which was manufactured at their facility in La Grande, OR. But when it comes to ordering replacement parts, they suggested I contact our dealer. Understandable, but interesting, considering our package was was shipped from La Grande. They did however help me identify the replacement part I needed.
Apache Camping in Portland, OR was also helpful in getting us the part we needed. Even if it did take a couple days of email communication since we are without cell phone service here at the Stillwell Store.
For our 24-5N we needed the gearbox that attaches to the Venture 9000PK 12v DC 30 Amp motor that drives our landing gear.
How to Replace DC Motor Gearbox
On our 24′ Arctic Fox the DC motor that drives the landing gear is clearly visible inside an outer compartment. Thankfully, this makes it easily accessible for maintenance. I took the following steps to replace our gearbox, and offer a few tips and precautions below to help anyone who may need to do the same.
1. Remove the retaining bolt from the sliding sheath on the square shaft that drives the opposite leg. Slide the sheath back to expose the gearbox drive shaft that powers leg movement.
TIP: I keep a few of these bolts on hand as they can vibrate loose and disappear, causing a panic attack and the need synchronize your front leveling jacks.
2. Remove plastic retainer that secures gearbox onto drive shaft so motor assembly can be removed from leg. A small screw holds this in place.
3. Slide gearbox with motor attached off the drive shaft, moving the shaft to opposite leg aside as necessary. The manual override drive shaft attached to the gearbox will easily slide out of its housing.
NOTE: If your motor has ample wiring attached, there is no need to disconnect any wires. Simply rest the motor with wires still attached on the compartment floor or a table outside the door. If you must disconnect wires, be sure to mark them for easy reference.
4. Remove DC motor from the attached gearbox.
NOTE: Four bolts attach the motor to the gearbox, but only the two long bolts need to be removed. If you do remove a short bolt, replace it to keep the motor intact and remove the two longer ones.
5. Note the alignment and position of the gearbox as you remove it, and replace it with the new one.
6. Re-attach the motor assembly onto the drive shaft by moving the opposite leg shaft aside and inserting the manual override shaft into its housing. Then align the center drive nut of the gearbox onto the drive shaft.
NOTE: Consider fitting the gearbox alone onto the shaft first to ensure a proper fit!
I neglected to do so, only to discover that the new gearbox fit extremely tightly on the drive shaft. I remedied this by removing the motor from the gearbox so I could more easily force it into place, then re-attaching the motor.
7. Activate landing gear switch (or use manual override wrench) to properly position the screw hole in the drive shaft so you can re-attach the plastic retainer.
NOTE: Synchronize leg length before reattaching opposite leg drive shaft!
If you have moved the motor after attaching the gearbox to the leg, ensure that both legs are the same length before proceeding. Measure the distance from the frame to the lower end of the sliding section on the opposite leg, and extend or retract the leg with the motor attached to match.
8. Re-attach the opposite leg drive shaft, adjusting the drive shaft as needed to align the bolt hole by activating the landing gear switch slightly, or using the manual override wrench.
9. Secure the opposite leg drive shaft with the retaining bolt.
Hopefully you have no parts left over, and when you test the motor the gears purr like a kitten without any chunky noises or dancing about of the motor.
Preventative Maintenance to Avoid Landing Gear Repair
After full-timing for more than five years, damage to our well used gear box is to be expected. Northwood, however, informed me that over-extending the legs can cause extra stress on the gearbox potentially damaging the gears. Interestingly enough, I dissected our old gearbox with the idea of getting a picture of some damaged gears, but everything appeared to be intact. I was reassured, however, to hear that the the landing gear motor rarely goes bad, and my assumption that the gears were going out was correct. I kept my old one for spare parts just in case.
NOTE: Never over extend the landing gear on your trailer!
When I inquired if there could be anything within the leg itself causing the issue I did discover one more rather alarming precaution. Over-extension can cause a mechanical failure inside the leg resulting in total inoperability, which can only be fixed by replacing the entire leg… not something you’re going to do by yourself in the middle of the desert!
All Feedback Welcome
Did you find this post useful? Please feel free to comment with your own helpful tips regarding this repair, or provide advice for doing similar jobs on different trailer types.