Common Fixes for the Shuddering Transmission

We get a lot saying our ATF solves the problem after trying about everything else!

Here are a few common reasons why your transmission may shift erratically, jerk or hesitate.

Low fluid level
Depleted fluid frictional properties
Poor cold-temperature fluidity

Start with the easiest fix

There’s an old adage when troubleshooting: start with the least expensive and simplest fix. In this case, check the transmission fluid level first. Low fluid can prevent the transmission from shifting properly. It’s important to find out why the fluid is low and fix any problems. It could be a leaky seal or other mechanical defect. Otherwise, adding new fluid won’t ultimately solve the problem.

Worn fluid equals poor shift quality

Transmission fluid that has aged and lost some of its frictional properties can also lead to poor shift quality. When your vehicle’s computer tells the transmission to shift gears, hydraulic pressure (provided by the fluid) squeezes a series of plates together inside a clutch pack to connect the engine to the transmission output shaft and route power to the wheels. The fluid’s frictional properties play a vital role in ensuring the clutch plates bind together properly and gear shifts occur seamlessly. Over time, the frictional properties of the fluid can degrade, leading to elongated, jerky or inconsistent shifts. In this case, it’s time for a fluid change. How do you know for sure the fluid is worn? The only definite way to find out is to conduct used fluid analysis. However, fluid that smells burnt or appears dirty is likely due for a change. It’s best practice to change the fluid before the frictional properties are depleted and poor shifting is experienced since poor shifts can cause the clutches to wear more rapidly and lead to bigger issues that need mechanical repairs.

Be aware of “adaptive” transmissions

One interesting note affects newer vehicles equipped with adaptive transmissions. These units “learn” your driving habits and the characteristics of the fluid to adjust shifts accordingly. As the fluid loses its frictional properties, the computer compensates and adjusts transmission performance. If you’ve recently changed your fluid, the computer may still operate as if old fluid is installed, causing poor shift quality. In these cases, keep driving and eventually the computer will “relearn” your driving habits and the behavior of the new fluid and adjust accordingly. The problem was significant enough on some 2012-2013 Ford F-150s to cause Ford to issue a technical service bulletin (TSB 13-1-10).

Your transmission fluid’s frictional properties are vital to best performance

To demonstrate its outstanding performance, AMSOIL Signature Series Synthetic Automatic Transmission Fluid was tested in taxi cabs operating in the intense heat of Las Vegas. First, the frictional properties of new fluid were tested. Then, after more than 180,000 miles of work in a fleet of taxis, the fluid was tested again. As shown in the graph, the fluid maintained nearly identical frictional properties to new fluid after 180,000 miles of severe service. That translates into solid, confident shifts day after day and long transmission life.

Cold weather can reduce shift quality

When the temperature drops, transmission fluids with poor cold-flow properties can thicken and cause elongated and hard shifts until the fluid has warmed up enough to flow properly. Switching to a high-quality synthetic transmission fluid will help. Synthetics don’t contain waxes, as conventional fluids do, so they remain fluid at lower temperatures for improved shifts during cold weather.

The best transmission fluid available won’t fix a broken transmission. But using high-quality synthetic transmission fluid can help improve shift quality and maximize transmission life.

The Fool Said I Can Use 20W-50 In All Three. What?

Some V-twin motorcycles, like modern Indian and Victory bikes, use a shared sump, meaning they use the same lubricant in the engine, transmission and primary chaincase. Most Harley Davidson motorcycles, however, use a separate sump for each lubricant. This presents Harley (Don’t forget about Davidson) owners with a choice: Use the same lubricant in all three areas of the bike, or use a separate lubricant formulated and labeled for each area. Here, we offer guidance for deciding what’s right

For the record, AMSOIL recommends AMSOIL 20W-50 Synthetic V-Twin Motorcycle Oil (MCV) in the engine, transmission and primary chaincase on most Harleys (consult the Motorcycle Product Guide at amsoil.com for specific recommendations). It offers…

Convenience. Riders buy and install one lubricant. This reduces cost and results in fewer half-used bottles of oil lying around the garage.
Simplicity. Remembering to buy one lubricant is far easier than remembering three.
Great all-around performance in all three areas of the bike.
It’s what the upper brass at AMSOIL use in their bikes.

We formulate 20W-50 Synthetic V-Twin Motorcycle Oil to be an excellent all around lubricant. It delivers outstanding engine protection due to its proven ability to fight wear, reduce heat, maintain cleanliness and prevent corrosion during storage.

See why the 50 weight qualifies as a 90 in the transmission.

Synthetic V-Twin Motorcycle Oil also boasts a shear-stable formulation. It resists viscosity loss despite the intense pressure and churning action of high RPM transmission gears, allowing it to deliver reliable transmission protection. Synthetic V-Twin Motorcycle Oil meets JASO MA/MA2 standards and is wet-clutch compatible for excellent performance in the primary chaincase. Its frictional properties are dialed-in to allow the clutch plates to engage and disengage without loading or slipping for smooth shifts.

Despite these benefits, some riders question the practice of using one lubricant in all three areas of their bikes. They have a difficult time accepting that a motor oil can also protect the transmission and primary chaincase.

I don’t think so. My Mechanic always said you have to use different oils. – That’s partially true…

If you believe this to not be true we make the separates for you. Debate free oil options! And yes, they are more dialed in.. This is why we offer Synthetic V-Twin Transmission Fluid (MVT) and Synthetic V-Twin Primary Fluid (MVP).

What are the differences?

In essence, Synthetic V-Twin Transmission Fluid and Synthetic V-Twin Primary Fluid are formulated to protect just one area of your bike rather than three. This specificity allows us to engineer each lubricant for its precise application.

Transmission Fluid

Synthetic V-Twin Transmission Fluid has a higher viscosity than 20W-50 Synthetic V-Twin Motorcycle Oil. A higher-viscosity, or “thicker,” lubricant can help quiet noisy transmission gears and enable smooth shifts. The lubricant develops a slightly thicker fluid film on gears, which provides cushion to help diminish loud “thunks” and gear noise.

Again, we realize that’s what people want and in some cases it’s beneficial to the gears but it’s slightly thicker than the OEM specifications or better put – on the high side of the range. The only real downside other than cost is less efficiency in cooler weather and a change in overall MPG.

Primary Fluid

Likewise, AMSOIL Synthetic V-Twin Primary Fluid is designed only to protect primary chaincase components. Its viscosity is similar to an SAE 50 motor oil. Formulating it as a straight-weight lubricant naturally offers an advantage in shear stability over other multi-viscosity lubricants. (AMSOIL 20W-50 Synthetic V-Twin Motorcycle Oil is absolutely shear stable and will not thin out from mechanical activity.) This helps the fluid remain thicker, which helps it cling to the compensator without being “flung off” as easily for maximum protection. In Harleys, the compensator acts as a shock absorber to prevent engine vibration from affecting the transmission. Compensator wear often leads to a knocking or ticking noise.

Synthetic V-Twin Primary Fluid also clings well to the chain for excellent wear protection. And its wet-clutch-compatible formulation meets JASO MA/MA2 requirements.

Many buy this because some bikes have issues shifting back to neutral. AMSOIL Primary Oil makes it much easier for the linkage to catch neutral when you need it.

One oil or three?

So, which is the better route for Harley owners? Either way you can’t go wrong but examine if you identify with the issues requiring the 2nd choices.

For riders who desire the simplicity and convenience of using one lubricant for all three areas, following our primary recommendation of 20W-50 Synthetic V-Twin Motorcycle Oil in all three areas is the best choice.

For riders who prefer lubricants dialed in for each area of their bikes and don’t mind a few extra bottles of oil lying around the garage, steer them toward our full line of V-twin lubricants.

Either way, they can’t go wrong.

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Tag: clutch plates

Common Fixes for a Transmission that Jerks or Hesitates