But furthermore, the question may have already popped into your mind: When might I need to get a forklift torque converter? That’s a great question, friend, and it deserves its answer….

First of all, whenever you notice any symptoms or “clear signs from heaven”, as some rather call them, then you can know for sure that it’s time to replace. The first sign would be that the current torque converter on your forklift has been overheating. This is more rare than would come to expect, and the only truly viable fix is to discontinue use of the forklift and get a replacement for this part as soon as reasonably possible. Another symptom may include that of high stall speeds --- this is a definite one you should watch out for and can’t afford to ignore at any cost.

Also, has the forklift been making strange noises --- I mean, stranger than usual? Then this is another clear sign that you need to get the torque converter on it fixed ---- or changed out. Dirty fluids and slipping are also common signs. Watch out for them.

So in essence, we’ve seen the forklift torque converter, briefly. You got to see how it works. And you got to see when it needs to be replaced.

Forklift Torque Converters: A 101 Technical Guide.

What they are and what they are for...

Forklift torque converters are essentially types of fluid coupling that can transfer any related prime mover’s rotating power, as needed, in order to get the operation vehicle moving along as it should. Similarly to the TC in a car, the TC in a forklift can work in much the same way, respectively. The prime mover aforementioned acts in much the same way as an IC or Internal Combustion engine would, with respect to any rotating driven load as well.

Within certain cars that use automatic transmission, furthermore, the TC will work to connect the load to its power source. One may usually find the load carefully placed in between both the engine’s transmission and its flex plate. Within a manual transmission, or stick shift, car, that same load may be found in a similar area, which would be referred to as the “mechanical clutch”.

And in addition, the TC’s main character trait, that distinguishes it the most and truly fulfills its purpose, would be that of none other than its very ability to duplicate --- or multiply, in a sense --- the torque. This happens when its output rotational speeds have diminished. It occurs when they’re so low that fluid protruding from the turbine’s curved vanes now deflects off the stator. It’s been locked against its clutch, which is of a 1-way nature. Thus, what you get is something quite similar to a reduction gear, all in all.

Even more details on this and on how TC’s specifically work....

Moreover, this mentioned features extends far beyond the traditional simple fluid coupling and doesn’t merely just match the rotation speeds while not being able to multiply the torque. It reduces the power, by the way. Some of these mentioned devices additionally come with their own lockup mechanisms that will rigidly bind their engines to their transmissions. This will usually occur when the speeds of both are at a near or full equivalent and is intended to avoid slippage, in addition to efficiency loss that may come as a result.

And forklift TC’s do not follow what auto transmissions use for their TC’s, respectively, which would be that of hydro-kinetic device or even hydro-static systems, most often seen in smaller machines the likes of compact excavators and products similar. In forklifts, overall, the processes and systems are not always as hydraulic as they are in cars. And in terms of mechanical systems, to further add, many varied mech designs exist the use of continuously variable TC transmissions as well. These may also multiply one’s torque. They’ll often include the Constantinesco torque converter, for one, which is entirely pendulum-based, as well as a variomatic that can provide its own expanding pulleys and a utility belt drive.

In addition, a disk-drive transmission, for more adequate friction gearing, of the Lambert style, may be included into the mix. And besides forklifts, and even cars, for that matter, these types of TC’s could even serve other uses, as well. See a few below:

1. Marine propulsion systems
2. Forwarders
3. Numerous types of heavy-duty movers
4. Transmissions of the industrial power kind, such as with railway engines, construction equipment, drilling rigs, winches and even conveyor drives. (Notably, forklifts using TC’s would fall within this category.)

Other facts one should know about them….

Note that the forklift TC you use will generally carry 3 operational stages by which it runs, of which you should learn:

The first is the stalling stage, also just called “stall”. It’s when the impeller’s getting the proper power through the prime mover but its turbine has difficulty in rotating. At this unique phase, the TC is able to produce max torque multiplication, given that the required amount of input power has been properly supplied beforehand. The multiplication that naturally ensues, as a result, is one many have come to know as the stalling ratio or stall ratio, in short.

Next comes the accelerating stage. As you accelerate, a noticeable difference begins to arise between the turbine speed and your impeller. Here, the torque multiplies far below what the stall ratio would.

Last but not least, the coupling phase has more to do with when 90 % or above (in impeller speed) has been reached by your turbine. At this point, all torque multiplication endeavors have come to their halt, and your TC behaves acts as more of a fluid coupling altogether. You may see some fuel efficiency increases at this stage.