Massey Ferguson DynaShift Transmission Troubleshooting: Issues and Fixes

The DynaShift Transmission was introduced in the Massey Ferguson tractors in 1992. It added an extra four-speed planetary unit to the tractor's traditional eight-speed high/low gearbox. The DynaShift system provided an extra four power shift speeds to every gear, culminating in a total of 32 forward and 32 rear speeds to the Massey Ferguson tractor.

The extra speed, selected using a small lever on the dashboard, has added reliability while providing easy operations and excellent speed control for this tractor.

How the Dynashift works

The Dynashift transmission system comes with two shift levers, one for selecting range and gears while the other lever is the forward/reverse shuttle selector. The MF gear selector has a four (1,2,3,4) gear range with an 'H' pattern. To change the gear range, the operator places the lever into the neutral position and then taps it to either Hi or Lo. The Dynashift lever is located on the left of the steering console and contains the Dynashift ratios A, B, C, and D shifting system. The gear and range shift (1,2,3,4) uses the clutch pedal while the Dynashift (A, B, C, D) system is clutch-less. There are eight forward and eight reverse gears each with a four-speed power shift.

In this article, we shall discuss the most common DynaShift transmission problems/issues and provide insights into those issues and how to fix them. It is important to note that while it is practical to carry out some repairs on the Massey Ferguson at home, the complexity of the modern-day tractor requires expert input to deal with and fix issues that may arise from time to time.

What are the Most Common Problems with the Dynashift?

1. Gears Failing to Shift

The DynaShift transmission has intermittent shifting problems where the tractor fails to shift gears when the Dynashift lever has been moved. The dash display indicates the changes but the gear shift does not happen practically. The problem is compounded by the fact that the gears change when the clutch is depressed and the tractor is stationary, but cannot change with the Dynashift lever when the tractor is moving.

These transmission shift problems could be caused by failed solenoids or switches. The gear shift range in the Dynashift transmission is electronically controlled by a group of four solenoids situated on the right side of the transmission box. When the tractor fails to shift the gears or fails to completely move, then the solenoids or the switches are the most likely having issues. The solenoids control the switches which do the actual shifting when the Dynashift lever is engaged.

Check to find out whether the solenoids are working properly. It could be rusty wiring at the solenoids or those passing under the cab. Also, check the switches that are linked with those solenoids to ensure they are all working as expected. If they are found faulty, the solenoids or switches should be replaced with new ones. The process of replacing a solenoid or a switch is pretty simple and should not trouble you.

Sometimes, the problem of Dynashift gear transmission failure could be caused by repeated heavy knocks on the underside of the transmission. The regular knocks may shear off the transmission drive shafts. This may cause the synchro to wear on the transmission, leading to intermittent failures on shifting. Although this is a rare problem since the MF is made for tough heavy-duty operations, it is still a likely cause of transmission shift failure.

If found out that the synchro has been damaged by knocks, then the gears have to be replaced.

2. Jumping through the Gear shifts

Another common problem with the Dynashift transmission is the gears jumping from one shift to the other on their own regardless of what the operator selects with the Dynashift lever. Normally, the lever selects between A, B, C, or D. You may find that when you shift from D to C, the shift is not engaged right away. After some time, the shift moves to D, then to C before moving back to D again. The transmission system lacks consistency when shifting between certain levels, while it is consistent with others.

These inconsistencies tend to make the operator not sure how to shift the gears. Every time the Dynashift lever is moved, the gears remain in the former position for some time before practically engaging. The operator may be forced to downshift for the transmission to up-shift, or vice versa. Headache.

This problem could be caused by a faulty Dynashift lever, failed hydraulic filter, or a bad electrical ground

• Faulty Dynashift Lever

The problem could be caused by a faulty Dynashift lever. The lever is connected to four micro switches which send signals to the auto-2 box based on the A-B-C-D Dynashift gear selection sequence. The signals then switch on the solenoids which then relay the selection to the transmission gears. Normally, the switching process is slow, but when the lever is faulty, the switching process is inconsistent and uncoordinated. The lever must be replaced.

• Bad Electrical ground

The Dynashift Transmission system is designed to perform a self-check at all times when the MF tractor is started. The computer system shifts through the ABCD gear system before settling on the last level the shift was shut down.

However, if the electrical ground is faulty, it creates a faulty current reading which simulates the tractor shut down. As such, the computer carries out the self-test once again by shifting through the gears before repeating the whole process over and over. Since the self-test is a slow process, you may shift the lever before the self-test is over, but the computer must complete the self-test regardless of your lever shift. Sometimes, this problem becomes more complex when the Dynashift begins to shift/change on its own or reset itself when you depress the clutch pedal.

Use a multi-current test kit to troubleshoot any faulty electrical wire. The problem could be solved by replacing the computer. Equally, you can easily ground the computer by connecting a wire to the computer ground terminal and fixing the other end of the wire to the mounting bolts. The computer ground will be restored.

3. Stuck in gear

Despite its admirable reputation, stuck gear is one of the most common problems of the MF tractor. When the tractor gear is stuck, the tractor cannot move or perform any other activity. The MF gear/Dynashift transmission has two shift rails and a back lock where the shift fork operates. The lock, located at the back of the lever is controlled by a spring which prevents a simultaneous selection of gears.

The gear gets stuck when the spring lock that controls the shift fork gets worn out, allowing the shift lever to slip into the wrong shift rail. Since it has no tension due to wearing out, it prevents the lever from getting back to its correct rail. The gear gets stuck.

To fix this problem, you will require to:

• Put the MF tractor on a fairly level ground to remove any stress on the transmission system.
• Put the gear and the Dynashift levers into neutral positions.
• Remove the filler pug to have a clear view of the shift fork and the stuck gear.
• Depress the clutch pedal and cautiously use a screwdriver to free the stuck gear. Push the gear to free it depending on which gear it is stuck in. If it is stuck in the first or third, push the lever backward, if jammed in the second or fourth, push the lever forward, and if stuck in reverse gear, then push the lever forward.
• Make sure you do not push the lever too hard as it will fly out and stick in the opposite gear position.
• Ensure you push the shifter to the center which is its neutral position. From here it can be shifted to the required position/gear.
• Then, replace the worn-out spring lock to avoid the lever getting stuck again.

This problem can be avoided in the future through mindful/cautious gear shifting and regular checks on the spring lock to ensure it is at the right tension range.

4. Excessive Transmission Noise

At times, the MF may produce excessive noise from the transmission gears or console. This could be caused by worn-out gears, damaged/defective shafts, incorrect backlash, bent shift forks, clogged transmission filters, or low transmission fluid.

• Worn-out gears- replace them with a new set and adjust the backlash to align properly with the new set.
• Damaged shift forks/shafts- replace with new ones
• Low transmission fluid/clogged transmission filter- unclog the transmission filter and fill it up with new oil or top up the oil.

5. Faulty gear mechanism

Occasionally, one may find it difficult to shift gears in the Dynashift transmission system. This could be caused by some of the fore-mentioned issues as well as a worn-out gear shift linkage, or worn out/improperly adjusted clutch. If the entire gear mechanism is having issues, the Dynashift transmission will also bring out operational hiccups. 

These issues can be rectified by pinpointing the specific area/component with a problem and rectifying it accordingly. Installing a new gear shift linkage will eliminate the gear shifting problems. Issues related to the clutch should be resolved by either adjusting the clutch to the correct position or replacing the bottom-of-clutch switch located in the clutch pedal box if it is faulty.

Though the Dynashift transmission system is an advanced MF tractor technology, it usually brings out issues that reduce its operational abilities, thus compromising reliability.