PTO Winches and FAQs

PTO winches are still manufactured today, but they are not marketed to the recreational user. There are still commercial uses for PTO winches, but most recreational users prefer electric or hydraulic winches. If you want a PTO winch, you'll probably have to find one used. You'll need to find the appropriate PTO adapter as well as the winch, several variations were available.

PTO Adapters

PTO Winches

Winch Essentials

Of all the different properties of a given winch, the line pull rating is the most important. It is the maximum static load the winch can exert on the cable. This will be achieved on the first wrap of the cable on the drum. For every successive wrap of cable on the drum the winch's torque decreases 12%. This must be taken into account when selecting a winch for your 4X4.

The line pull, line speed, and current draw (applicable only to an Electric Winch; a Hydraulic winch does not have this problem) indicates when a weight of X lbs is pulled, it will be pulled at Y ft/min using Z amps. These numbers vary widely from winch to winch. They should be an important consideration in a winch purchase. It is best to ask an experienced winch owner to determine what is best for you.

Weight is an indicator of the construction of the winch. Winches must be very STRONG. Too little weight means too little metal used in the construction. Too much weight could mean that your front end will sag. A benefit of the Hydraulic winch is that it does weigh less.

Q. How do I select a winch for my truck?
A. The most important thing to consider when selecting a winch is whether it is capable of pulling 1.5 times the gross vehicle weight (GVW) of your vehicle (don't forget to take into account that 12% drop in pulling power for every extra wrap of cable on the drum - a 9000lb winch has a line pull of approx. 7000lbs on the third wrap). GVW is the real world weight of your vehicle, i.e. fully loaded. So fill up your gas tank, load up all those off-road goodies, tools, hi-lift jacks, people and go get your vehicle weighed.
Q. What do the different winch gear systems mean and what difference will they make when I'm operating them?
A. There are three common gearing systems, worm gear, spur gear and planetary gear. They all do the same job, gear down the high speed motor to a low speed high torque winch drum. The gear reduction ratio is by how much the motor's output revolutions are reduced for the spindle. The greater the reduction, the more revolutions the motor has to turn for one spindle revolution and the less the motor has to work for that revolution. The difference in the gearing systems is mainly in their transfer efficiency.

The worm gear has a transfer effiency of 35-40%. This causes the winch to be self-braking even under heavy loads, but this means the unit will need a clutch mechanism for free spooling. Worm gears offer the most reduction, very high reliability, built-in braking mechnism, and generally a slower winching speed.

The spur and planetary gear systems have efficiencies of 75% and 65% respectively. This means they have a tendency to free spool when loaded, therefore a braking mechanism is needed. Planatary gears are the most common and provide both strength and smooth operation with good resistance to torque loads.

Q. I've noticed while looking through the manufacturer's catalogs that there are different types of electric motors. What is the difference between series wound motors and permanent magnet motors? Is one better than the other?
A. An electric motor basically has two major parts, the stator and the rotor (or armature). It is the job of the stator to produce a magnetic field which will cause the rotor to rotate when an electric current flows through it.

In a permanent magnet motor, the stator uses permanent magnets. This means the current drain on the battery is lower than series wound motors (which uses field coils in the stator). Permanent magnet motors are good for light and medium duty winches, but winching time and load has to be carefully monitored as they tend to overheat. Series wound motors are used in heavier duty winches, but tend to cost more.

Q. Will my electrical system cope with the extra load of an electrical winch?
A. For most pulls, yes. There a lot of people out there with one battery, stock alternator, and a winch. Keep in mind though that running a winch is the equivalent to moving your truck on the starter motor, there is a tremendous draw. Most electric winches draw around 400 amps at full load which is far more than even a high output alternator will produce. Stock alternators typically produce 40-90 amps at peak output and the battery will keep up for only so long. Because of this, many people install high output alternators and dual battery systems to support an electric winch.

When shopping for a high output alternators, remember to consider alternator output at idle, these figures can differ wildly, especially on older models. Regardless of what alternator you have, it is a good idea to keep up the RPMs while you are winching if possible. Most alternators have peak outputs near cruising RPMS. Also, keep you truck running after winching to give your battery time to recover.

Upgrading the battery or going to a dual battery system is also a good idea. The more cold cranking amps your battery (or batteries) produces, the longer you can pull without your engine running. An electronic battery management system is also a good idea to issolate the batteries.

After you have got power to the winch you will need to get it back to the battery. Ensure your grounding system is capable and all connections are clean, this is where most systems waste power. The best grounding systems will use large diameter cables (such as welding cables), the battery negative post connects to the engine block, the alternator ground connects to the engine (usually through its case) and then the frame is connected to the engine using a grounding strap. The best bet is to connect the a ground directly from the winch to the battery.

Q. I want to be able to winch from either the front or the back of my truck, are the receiver mounted winches any good?
A. Receiver mounted winches are very useful, but remember their static pull load is limited by the receiver they fit into. For a class III hitch that is 5000lbs. Because of this, receiver mounted winches are not really suitable for full sized trucks.
Q. When I buy my winch, what comes with it, and what else do I need to start using it?
A. Most winches come with nothing, but some places do a deal which includes the remote cable control and fairlead hawser. You will also need the mounting kit for your vehicle. I strongly recommend you buy the winch manufacturers kit. It has been designed for that winch and vehicle with all safety aspects considered. Home made winch mounts are disasters looking for a place to happen.

Your winch will now work, but it is limited to straight line pulls between two vehicles. The addition of the following items will greatly increase your winch's usefulness - Tree saver straps (never wrap a cable directly round a tree, you will kill the tree and kink your cable), a couple of clevis pins, snatch blocks, a choke chain and of course thick leather gloves.

Attach tow hooks to the frame on all four corners of your vehicle.

Q. What safety equipment will I need?
A. You just need your leather gloves and common sense. Never handle the cable with bare hands, a frayed cable can cut skin to the bone. The most common winch accident is getting your fingers caught in the cable as the last of it winds onto the drum. Always use the remote control cable when winching, and keep every one out of range of the cable .
Q. What other safety considerations are there?
A. Be aware that a broken winch cable can have enough force in its whiplash to cut through a truck's roof and windshield. Imagine what would happen if the cable met a person. A cable that hits a small tree will tear the tree down. A cable that hits a large tree can wrap tightly around a tree so a person behind the tree is not necessarily safe. Solid objects such as hooks and snatch blocks will fly through anything, including a truck's hood, if a cable breaks. People should stand well out of range of the cable and never in line with the cable. Furthermore, if a cable breaks, the truck being winched may roll downhill, so never stand downhill of any vehicle being winched.
Q. Is it common to break a winch cable? Should I carry a spare?
A. No to both questions. A properly maintained cable is very reliable (see question about maintenance) and carrying a spare will only increase the risk of damaging it. Winch cable is aircraft grade cable and has a breaking strain of 32,000lbs - much higher than the capacity of the winch.

It is much more common for for snatch blocks and anchor points to break because they were poorly rigged up. It is a good idea to drape a heavy cloth jacket over the cable to limit the whiplash if something snaps. If someone has to steer the vehicle being winched, then raise the hood for extra protection. Ensure all anchor points are firm.

Q. Is my winch maintenance free?
A. Although many people seem to think the answer to this one is yes, the answer is really no! I have met a number of people in the mountains stuck, with a winch that won't work. A little care and preventative maintenance would have ensured its reliability.

Your winch should be maintained on a regular basis. Lubricate all required points, inspect all mounts, pulleys, straps and clevis pins, check they are not damaged, or showing signs of fatigue, and are free of moisture. Inspect your remote control lead and electrical system for damage and chaffed insulation. Make sure all terminals are corrosion free and tight. After each trip unspool the cable. Check for kinks and frayed strands (damaged cables should be replaced). Lubricate cable with a chain and cable lubricant (normal grease will collect dirt) and wind back onto drum.

Q. What does using a snatch block achieve?
A. Basically it doubles your available pulling power (in fact it's an increase of 85% after safety considerations). It will also allow you to perform pulls at an angle to your truck. People are rarely considerate enough to get stuck straight in front of you.
Q. When I double up the winch line using the snatch block, where should I attach the return line.
A. If the snatch block is attached to another vehicle, which you are trying to free, then the return line should be connected to a third vehicle or tree, to spread the load.

If the snatch block is anchored to a tree and you are trying to free yourself, then the return line should be hooked onto your vehicle's frame. DO NOT hook it back on to the winch mount as this will effectively double the load on the mounting plate.

Q. What is the best way of anchoring my vehicle when I'm trying to winch another vehicle out of trouble?
A. Anchor your vehicle to another vehicle or any other fixed object using your tow strap, tree saver, choker chain etc. The one thing to remember is attach the anchor strap to your vehicle at the same end as your winch, otherwise you may stretch your vehicle's frame. Often, simply hitting the brakes will be sufficient to hold your vehicle in place.

Electric vs. Hydraulic vs. PTO

Just when everyone thought the electric vs. PTO winch war was over, along comes the hydraulic winch. There are still pockets of resistence, but generally, electric winches have won out over the PTO winch. Enter the hydraulic winches and another set of advantages and disadvantages.

The PTO (Power Take Off) winch is driven by a small drive shaft that is driven by a PTO adapter that bolts to the transmission or transfer case. Only certain transmissions and transfer cases have PTO ports (e.g. T-18, SM-465, Dana 18, ...). Most electric and hydraulic winches have only one speed, but with a transfer case PTO port, shifting gears can be used to change line speed, torque, and direction. Transmission PTO ports drive off the counter shaft, so they work in one direction and have one speed that can be varied by engine RPM. Since engine power drives the PTO winch, your engine must be working to operate a PTO winch. This is probably the biggest disadvantage of the PTO winch since your engine isn't likely to be running for long when your truck is upside down or under water in a raging river. Not long enough to run out the cable anyway.

The electric winch does not require the engine to be running to work, which is it's biggest advantage. The big argument against the electric winch in the past was it would drain you battery and there was no way your alternator could provide sufficient power for a long pull. The automotive industry has made great improvements in alternator and battery technology over the past years which has given the advantage to the electric winch. Batteries have more power and alternators have higher outputs. An electric winch might even work if your truck is upsidedown or under water.

Some of the advantages of the hydraulic winch are pulling power, pull duration, and weight. The hydraulic winch runs off your existing power steering pump. There is no need to upgrade alternator of battery for the winch, but you may consider upgrading your power steering pump. If you don't have power steering, convert now, regardless of what winch you get. A hydraulic winch should be able to pull harder and longer than a electric winch with out over heating. Hydraulic winches are also much lighter than electric winches, putting less strain on your front axle and front springs.

Hydraulic winches suffer from the same disadvantage as the PTO winch, neither works when the engine isn't running. The hydraulic winches I've seen have a real slow line speed, this could an advantage under some circumstances, but generally this is a disadvantage. There is a two speed model, but the high speed is not for use under load. Another disadvantage I've heard from people with hydraulic winches is the reduced ability to steer and winch at the same time.

Contributors

Some of the information on this page was originally prepared by Steve Williams in June 1993 as part of the Off-Road Mailing list FAQ. Some text has been modified and added by Terry Howe and others no doubt.