Servicing your Electric Winch

Steve Cassano — 4 March 2019

If you’re a serious 4WD owner and enjoy your remote travel, having the correct recovery equipment is vital. Headlining any serious recovery arsenal is the 4WD winch. 

Over the past few decades, the 4WD winch has evolved, introducing various designs to the market, the most common among these being the Power Take Off (PTO), high mount electric and low mount electric. 

In 2019, you won’t see too many PTO-style winches; over the years, several negatives aspects have forced them out of favour. Still, a few diehards swear by them because of their simplicity and strength (they run off the engine via the gearbox). 

Nowadays, it’s the electric winches (both high and low mount) that dominate the market. This type runs off a 4WD’s battery. Of the two, the high mount is less common, given it’s heavier (at around 50kg), more expensive (a WARN can be around the $3,000 mark), and not compatible with all bull bars. However, this type does tend to be more popular on comp trucks, due to its extra line capacity and quicker retrieval speed.

This leaves us with the low mount electric winch: easily the most affordable and popular winch among everyday 4WDers.

READY WHEN CALLED UPON

There’s no point to having a winch at the front of your 4WD if it isn’t going to work – apart from conveying serious 4WDer vibes, of course. Just like all accessories, winches need regular inspection and service to ensure they run efficiently and smoothly.

I lost count of the number of malfunctioning winches I’d encountered a long, long time ago. I’m referring to complete non-starts, smouldering terminals, the inability to unspool... the list of potential malfunctions goes on. But underlying almost all of these malfunctions is the install-and-forget mentality.

It pays to pay attention. You can usually tell a winch needs servicing from unusual grinding or loud noises, slow retrieval, inability to winch out, overheating during simple recoveries, or over-easy free spool. The main culprits of poor performance are mud and water ingress (especially salt water), as well as breakdown of seals, grease and lubricants. 

It needn’t be this way. Let’s outline how to overhaul a low mount winch to ensure it’s ready to work when you need it to.

DISASSEMBLE THE WINCH

Before commencing, remember you’re handling heavy components and an accessory that uses an electrical source for power. So, the first thing to do is to disconnect the main power from the battery to the winch, at the battery post. This is usually the cable that runs between the winch’s solenoid box and the battery.  

Once you’ve confirmed the winch is electrically isolated, it’s time to remove the three cables attached at the motor end of the winch, which are fed from the solenoid (check underneath, as there may be an earth cable there, too). 

Be careful removing the hex nuts, especially if they’ve not been accessed for a while. You don’t want to dislodge the bolts off the winch housing, because they are directly attached to the internals of the winch motor. Simply undo the nuts and label them, so you know which is which when it’s time to reassemble.

Next, undo the winch hook and feed the winch line back through the fairlead. To ensure a thorough service, you’ll need to remove your winch from the bull bar (or in some cases the winch mounting plate). If you’re lucky, removing the winch may simply require undoing four mounting bolts from underneath the bull bar. Unfortunately, other winches may require a tortuous procedure, involving a complete front bar removal, so have your friends on standby.

Once you’re confident all has been detached, lift the winch to your working table, taking due care with its weight. Now’s a good time to do your research or study the winch service manual, so sit down for a cup of tea or perhaps a beer.

WHAT YOU’LL NEED

To successfully clean and maintain a low mount winch you’ll need some basics, but fear not – dismantling a winch is a relatively simple task, easily within the realms of anyone equipped with common tools and consumables.

Whilst not mandatory, I suggest hunting down a service manual for your particular winch. In my case, searching ‘WARN service manual’ easily resulted in exactly what I was after. The document provided a fantastic illustrated step-by-step guide on dismantling, cleaning and proper reinstallation. All reputable winch manufacturers should be happy to provide one. If you have trouble finding yours, then the WARN one may potentially act as a suitable reference.

Next, gather the following: a few rags, wire brush, a set of allen keys (or sockets depending on your model), a few old paint brushes, a vacuum, a bottle of kerosene, high temp grease (moly-disulfide grease is good), machine oil (like that you’ll find for a sewing machine), and a large container to wash the parts in. Finally, don some old clothes. Things are about to get messy.

CLEANING THE GEAR BOX

The winch is comprised of three main parts: the electric motor (where the power cables enter); the drum/spool (which stores the cable); and the gear box (where most of the maintenance is usually required). First up, let’s tackle the gear box.

Firstly, unwind and remove your winch cable. Take the opportunity to inspect for damaged cable, and if you’re using synthetic, wash and hang dry your cable before reuse.

Once you’ve removed the winch cable, use a marker pen to ensure that you can correctly realign the housing when it comes time to reassemble.  

It’s important to ensure that the internal components and gears are reassembled in the exact position, so lay them out in order on a clean table to make life easier.  

Commence by undoing the hex socket cap screw that holds the free spool clutch lever. Once this lever is detached, set it aside for cleaning along with its rubber washer. 

Again, use an appropriate allen key to separate the housing ring gear and drum support by undoing the 10 hex socket cap screws. Set the sections down slowly to avoid parts falling out and going astray. Continue by carefully extracting all the gearing components, taking careful visual note, because there are subtle differences that can easily be missed. The internal parts are easily extracted by hand, with no tools required at this point.

Once all parts are separated and laid out, inspect for any wear or damage and take appropriate action if required. Thoroughly clean everything with kerosene (or another suitable agent), ensuring all old grease and any dirt is removed. 

Once satisfied, apply grease to the free spool lever O-ring seal, the ring gears, first stage and second stage carrier assemblies, the thrush washer, and – lastly – the third stage planetary gear, as you commence to reassemble the housing.

Next, apply a light coat of machine oil to the inside of the gear housing, the sun gear shaft and the three planetary gear bushings inside the carrier assembly. Be sure to apply machine oil to the machined surface of the gear housing, not grease, because the latter will hinder free spooling. 

Once all is satisfactorily cleaned, reassemble the parts and align the housing with your previous outer marks. It may take a little jiggling to align the gears, but it should ultimately set in place with ease.

(While you’re at it, it may be worth checking the large outer housing gaskets for wear. When I was last servicing my winch, they looked pretty ordinary, so I replaced them – for just eight dollars!)

Once snug, reinstall the 10 hex caps to a firm torque, then reattach and secure the free spool lever.

CLEANING THE ELECTRIC MOTOR

Good news: checking the electric motor is a simpler process than checking the gear box. Start by removing the two long bolts at the end of the housing. Then, separate the motor housing away from the drum, ensuring the armature shaft is moving out with the motor housing, else it’s a pain to realign (ask me how I know).

Once this the housing is detached, set aside then inspect the interior and drum bushings and casing for excessive wear, then clean with a rag and lightly regrease where appropriate.

Next, using a larger allen key, unscrew the two tie rods; this will allow access to the drum and internal brake system, once you separate the drum support. In many cases, it will suffice to dry brush clean around the interior of the drum, then reattach the drum support and tie rods. Whilst we could go further and disassemble the brake system and all the electrics, this may be unnecessary if the interior is in a relatively unsoiled condition. 

Next, using a thin, long paint brush, scrub in between the sections around the armature and bushes, subsequently vacuuming any accumulated dirt. In my case, the electrical motor and interior had no evidence of water or grime ingress, which makes me glad I chose a WARN. 

Once again, take care to realign the electric motor housing correctly, and be prepared for further jiggling to ensure the hex shaft lines up with the sun gear at the gear box end. Finally, once all is set properly in place, secure the housing with the two long bolts. 

FINAL STEPS

Before reinstalling the winch in its cradled position, it’s a good idea to toggle the clutch lever and check that the drum free spools smoothly and re-engages. If you’re one of the unlucky ones needing to reinstall your bar, I’d temporarily connect the power leads to check proper operation, before permanently reinstalling the winch.

Once the winch is all bolted back in and you’ve reinstalled the power cables, use a wire brush on the bolts, nuts and cable lugs to ensure good conductivity, given that constant exposure to the elements makes these subject to corrosion. For a few dollars, consider using rubber dust caps or stainless to protect these connections.

The penultimate step is to rewind the cable under moderate tension and connect the winch hook. The last step? Admire your work, knowing that next time you’ll be confident and ready to tackle the gnarly tracks on your bucket list.

Happy wheeling.