Harley 6 Speed Transmission Problems: Diagnose And Easy Fixes

The most common problems with the Harley 6-speed transmission include worn-out shaft bearings, stiff chain tensioners, gear slippage, and excessive noise and vibration. However, it doesn’t end here because riders also suffer from minor issues such as hard shifting, false neutral light, etc.

Transmission failures are quite expensive to overcome. But if you know about the problems beforehand you can avoid catastrophic transmission failures saving a lot of money and components. The following discussion will guide you to fix those before it’s too late.

Troubleshooting And Fix For Harley 6 Speed Transmission Problems

Knowing the exact problem type and troubleshooting it beforehand could save your gearbox from fatal, irreversible, and costly damage. Let’s discuss each of them in detail.

1- Internal Bearing Damage

After riding your Harley for a certain period of time, the excessive stress is on the internal bearing. 

This results in wearing it down and generating tiny metal strips inside the transfer case. 

It mostly happens when you are revving your bike in 6th gear with a minimal gear ratio. The stress from the engine puts enormous pressure on the bearing. 

Again, a faulty design, such as the massive gap between the clutch pack and the main shaft, also leads to bearing failure. 

Another major reason for the worn-out bearings is the automatic chain tensioner.  

The stock chain tensioner gets tightened over time but doesn’t recall back to the initial stage during downshifting or acceleration. 

The only fix for this issue is to replace the main shaft bearing. It will cost you around $50-75 for the part and extra labor charges. 

If you hear any growling or metallic grinding noise, then it could be an early warning sign of bearing damage.

Riding and revving up slowly in the 6th gear and not pushing the bike at high rpm in the 6th gear can keep your transmission healthy.

Read Also: Harley Davidson 1200 Sportster Common Problems

2- Excessive Noise At Higher Gears

Harley Dynas and Touring series with 6-speed transmission come with a major transmission issue of noise in 5th and 6th gear. 

It has been reported that spur gear as the 5th gear results in the additional whirring noise coming from the gearbox.

In addition to riding in fifth or sixth gear at high RPMs, the vehicle experiences unusually high vibrations. 

A permanent fix for this issue includes replacing the existing stock gearbox with an aftermarket one such as Bakers which has a spur gear system.

However, it might cost you around $1000 only for the replaceable part without labor cost. 

You can use certified and recommended transmission oils such as Amsoil or Spectro to lower the noise level.

3- Gear Slippage

One of the common issues that Harley riders encounter is gear slippage. It mostly happens when shifting in between the 5th and 6th gears.

Although it may seem like a minor issue, in freeways and while overtaking at high speeds gear slippage could be fatal. 

To get rid of this issue first try to adjust the clutch and clutch cable. This will cost you around $100 only.

However, if the issue persists you can try replacing the clutch disk and clutch spring. There are many aftermarket clutch springs but the Barnett clutch spring has a good reputation.

Read Also: Harley Davidson 103 Compensator Problems: Causes And Solutions 

4- Bent Transmission Fork

Bent Transmission Fork
Bent Transmission Fork

Shift linkage issues are one of the most common Harley 6-speed transmission problems. The primary reason for such an occurrence is a bent or damaged fork.

This results in improper contact between the gear grooves. Thus, you’ll find it difficult to shift stably. 

In order to fix this, you need to disassemble the entire transmission box, followed by replacing the damaged fork. But before opening things up you must check for transmission oil leaks. 

Low oil levels can sometimes cause the same and refilling with recommended transmission oil might save you from spending a lot.

5- False Neutral Light

It may not be a potential threat to the transmission system but could be fatal if misjudged. 

This minor defect was found in the newly launched Dyna 6-speed transmission motorcycles. Riders often found the Neutral lit up even though the vehicle was in gear.

This could give you false reading about the gear and cause fatal damage. Harley recalls all the Dynas released back in 2006 with such defects. 

If your bike has a similar issue and the model year, you can contact the official dealership to claim servicing free of charge.

Read Also: Solving Harley Freewheeler Problems: An Ultimate Guide!

Tips To Prevent 6-Speed Transmission Problems On Harley

Transmission problems are not cheap to treat. You can follow these tips to prevent 6-speed transmission problems in your Harley and elongate its lifeline.

  • Always check the transmission oil level and refill using certified oil after a certain mileage.
  • Do not overdrive at high gears and high RPMs especially in between the 5th and 6th gear.
  • Do not push your bike right after ignition. Allow the engine and transmission to get warmed up and well-lubricated.
  • Avoid engine lugging and aggressive shifting at lower gears.
  • Check the chain and belt tensions of the shafts.
  • Inspect the drained transmission oil for metallic chunks. If found, then it could be a sign of internal bearing damage.

Is It Safe To Drive Harley With 6-speed Transmission Problems?

It is not safe to drive Harleys with existing problems in the 6-speed transmission system. Sudden gear slippage, stuck gear, or false gear indicator can result in fatal accidents.

Besides, driving with an internal drive shaft bearing issue can damage the entire transmission system which may not be fixed.

Read Also: Solving Harley Milwaukee 8 Problems: An Ultimate Guide!


Check out these questionnaires from Harley lovers to get enlightened more about the 6-speed transmission issues.

How Much Oil Does Harley’s 6-Speed Transmission Hold?

Most Harley 6-speed transmissions hold up to 1 quart or 32 oz of transmission oil. However, some older models of Softail and Dyna with 6-speed transmissions can hold 28 oz of oil.

How To Accurately Shift A Harley 6-Speed Transmission?

The gears in Harley 6-speed transmission are arranged in sequential order. Shift down from the Neutral position for the first gear. However, the rest of the gears need to shift upwards depending on the speed and RPM.

What Are The Gear Ratios On A Harley 6-Speed?

The gear ratios of Harley’s 6-speed transmission are as follows: 9.311, 6.454, 4.793, 3.882, 3.307, 2.790. However, the gear ratios change depending on the regions of production.

What Year Did Harley Make The 6-Speed Transmission?

Harley introduced the 6-speed transmission system in 2006. The 6-speed transmission debuted with the Touring, Dyna, and Softail series. After 2007, most categories of Harley touring, grand touring, and trike models were converted to 6-speed.


Harley debuted the 6-speed transmission with some major faults including the shaft bearing damage. 

But with time, they developed the transmission including quality components. 

Hence, newer Harley doesn’t come up with transmission failures if maintained properly. 

However, it is better to routinely check your 6-speed transmission system to avoid any irreversible component damage.

Read Also: 4 Major Harley Davidson 103 Engine Problems & Solutions

Similar Posts