Subaru has been one of the many automakers that introduced a continuously variable transmission (CVT) into their lineup over the last few decades, promising benefits such as increased efficiency and decreased weight. Since 2014, the Subaru Lineartronic CVT has seen use in every Subaru model excluding the WRX STI and BRZ.
CVTs, including Lineartronic, operate differently than their traditional automatic and manual counterparts. For one, these transmissions forgo the use of fixed gears entirely, opting instead for a set of conical pulleys and a belt that offer the ability to dynamically alter gear ratio rather than relying on the set ratios of specific gears.
In this article, we’ll cover what Subaru’s Lineartronic transmission is, how it works, and the common problems that owners and prospective buyers of vehicles with this transmission should know.
What is Lineartronic
Subaru’s Lineartronic is a type of continuously variable transmission, and as the name implies, it is able to seamlessly vary the gear ratio of the transmission rather than switching between fixed gears.
Without needing to disconnect a clutch in order to shift, the transmission is able to continue seamlessly delivering power at all times, making use of power that would otherwise be lost to a disengaged flywheel.
As CVTs do away with fixed gears in favor of a system that allows for virtually infinite gear ratios, Lineartronic transmissions are able to select the optimal gear ratio for the exact engine speed at that moment. While traditional automatic transmissions would have to select the closest option from a fixed set of ratios, CVTs can instead switch to the perfect ratio without the need for shifting gears at all.
How Does Lineartronic Work?
As stated above, Lineartronic and other CVTs skip the need for fixed gears entirely. Instead, these transmissions rely on a set of two pulleys and a belt.
Both of these pulleys are slightly cone-shaped, with the radius tapering off towards each other. Between them runs a metal belt known as the V-belt, connecting the two pulleys.
This conical shape of the pulleys is important as it allows for alterations in the gear ratio. By extending or lessening the gap between the pulleys, the belt shifts to a different part of the cone with a different radius. By controlling the radii of each pulley, the transmission can produce virtually infinite gear ratios.
From the driver’s seat, CVT transmissions may not initially seem that different, retaining the traditional “P-R-N-D-L” gear selector seen on automatic transmissions. However, this is essentially where the similarities end.
Benefits of Lineartronic
Each of these differences culminates in an extremely efficient transmission, providing uninterrupted power at the perfect gear ratio for that exact RPM. CVTs can improve fuel efficiency by as much as 10% due to these unique characteristics.
The upsides of CVTs go beyond just MPG, however, as they also provide improvements in areas such as weight and size. The simpler design of CVTs along with the lack of need for bulky gears saves precious weight and improves the handling and performance of the vehicle.
This less complex design allows for cheaper manufacturing and maintenance, saving you money on service and repair down the line.
Common CVT Problems
Shuddering
One of the most common issues seen on Lineartronic transmissions, and CVTs in general, is a shuddering or shaking sensation felt in the vehicle’s chassis.
While a shaking feeling can originate from a number of different places, this symptom could be warning you of serious issues within your transmission. In many cases, shuddering is a result of a loose belt or pulley within the transmission.
When a pulley becomes loose, or the belt dislodges itself, the belt may slip from it’s intended track, causing the transmission to vibrate and shake as the belt turns. Allowing your CVT to run with a slipping belt is inviting further problems, and this issue should be taken care of as soon as possible to prevent expensive damage.
Whining/Whirring Noise
If you notice a grinding or whining noise while driving, it may be due to a failing bearing within your CVT. The pulleys’ bearings allow for smooth rotation and reduced friction, however, these bearings experience a great deal of wear from constant use.
When a bearing fails, the increased friction will often cause a disconcerting grinding noise. This sound can also be the result of a failing belt, but is a less common issue. If you hear an unusual noise from your transmission, you should have it inspected by a trusted professional as soon as possible to ensure no further damage.
Overheating
Like traditional transmissions, CVTs and Lineartronic rely on lubricative fluid to allow for low-friction operation and mitigation of heat. When this fluid has either exited the system through a leak, or has accumulated contaminants over time, the transmission may not be able to properly manage heat build-up.
An excess of heat in the transmission can cause a whole host of problems, including a burning odor, unusual noises, and the rapid deterioration of internal components. If left untreated, this could result in complete transmission failure.
Although Subaru of America states that their Lineartronic fluid can last the lifetime of the vehicle, many dealerships still recommend replacements around the 30K-60K miles range. If the vehicle is often used for towing, heavy snow driving, or other “severe driving conditions,” Subaru recommends having the fluid replaced around every 25K miles.
Subaru Transmission Services in Boulder, CO
Whether your Subaru has a CVT, automatic, or manual transmission, the specially-trained Subaru experts at Super Rupair have the experience and equipment to properly inspect, diagnose, and repair your vehicle! Give us a call or schedule online today to secure a spot with technicians who know your vehicle inside and out.