Allison Transmission has the 06 most common shift selector problems, including delayed shifting, limp mode, mis-adjustment of gears and levers, fluid leakage, stuck gears, and slipping gears.
Let us discuss these 06 most common problems and their possible solutions.
01. Delayed Shifting
Delayed shifting is one of the most common problems associated with automatic transmissions.
When the clutches that allow a car to move become sluggish and do not operate, it causes delayed engagement.
It may happen due to the shortage of transmission oil, which plays the main role in keeping the shift selector safe from frictional damage.
So, a shortage of transmission oil will make the clutches slow to operate and cause delayed shifting.
Your transmission is critical if your vehicle experiences shifting delays that last a minute or longer and needs to be checked as soon as possible.
Solution
To get rid of delay shifting, you need to find out what is causing it.
As it happens, due to the inadequate amount of transmission fluid, you will need to check the fluid level of your transmission system.
You will also need to ensure that the oil levels are normal.
A lack of optimal leakage in the oil pan can cause clutch damage.
If the oil level is below average, you must increase the fluid to a standard level to make your Allison transmission smoother.
02. Limp Mode
The Allison transmission has a feature called ‘Limp Mode’ that causes the transmission to shift automatically into third gear.
It changes gears automatically when the car is carrying too much weight or getting too hot, which could hurt the engine.
If car loads are too heavy, Allison’s protective feature activates the limp mode automatically.
If the engine control modules receive incorrect data about the vehicle’s load that may cause harm to the transmission or engine, the ECM turns on limp mode.
When the ECM activates limp mode, it locks the car in third gear and gradually reduces speed.
Solution
As there could be various reasons behind activating limp mode, first, you need to find out the reason for its activation, and then it needs to be fixed.
Some easy hacks sometimes work.
Follow these 04 steps to get out of limp mode:
- Turn your engine switch off for a few minutes, and then restart it.
- Check to make sure the coolant level is adequate. Use high-quality coolant for better output.
- Check your car’s air intake system. Dust and dirt can sometimes clog the air intake system.
- Check the MAF sensor data, O2, temperature, and throttle position sensors.
Replace the faulty parts to get rid of this problem.
03. Mis-Adjustment of Gear and Levers
Sometimes the gears and levers are not properly adjusted with the shift selector.
The engine clutches often get too short or too long due to repairs or other mechanical causes.
It is necessary to properly align the clutches with the shift selector to operate properly.
Solution
You can solve the misadjustment in 02 steps:
- Double-check the gear installation.
- If the gears and levers are found to be out of alignment, then take the car to the dealership for proper alignment.
They will check it and adjust the size of the gears and levers.
04. Fluid Leakage
Damage to the transmission pan from things like road debris can cause fluid to leak.
Seals in the transmission that keep fluid from leaking out wear out over time and allow fluid to leak out.
The torque converter needle bearings may also crack, allowing transmission fuel to leak from the crack in the torque converter.
Solution
The average cost of repairing a leaky transmission is very high.
If the transmission leaks fuel, try to find the cracked part and replace it as soon as possible.
Try to avoid leakage by maintaining the transmission as the company recommends.
05. Stuck Gears
The shift selector often gets stuck and doesn’t operate as it should.
It could be due to a lack of transmission fluid, limp mode, a broken linkage cable, a broken torque converter, or something else.
When the shift selector gets stuck, the vehicle starts to malfunction, harming other parts as well.
Solution
Replacing the defective part will fix the stuck gear issue.
If there is any problem with the shift selector, fix it immediately.
A faulty shift selector may occasionally be the cause.
The shift selector needs to be checked and fixed if it’s faulty.
Replace the converter.
Top up the transmission fluid to an optimal level.
06. Slipping Gears
Slipping gears occur when gears are changed without input.
Due to inadequate transmission fluid, the clutches get worn out and sometimes burn out, which results in slipping gears.
When the fluid level is low, it may cause overheating and reduce hydraulic pressure.
As a result, the gears fail to operate properly.
Torque converter issues and defective solenoids can also cause the gears to slip.
Solution
Check the fluid level; fill it up if it is less than average.
Check out the other parts.
If there are any defects or leaks in any parts, repair them as soon as possible.
If necessary, replace them to reduce defects.
To avoid slipping, check your transmission routinely and keep it under proper maintenance.
Final Thoughts
You may have to deal with some of the problems mentioned above with your Allison transmission.
To avoid these common problems, you should take good care of your transmission system before it gets damaged.
If the problem is severe, take it to a service center as soon as possible, or it will cause permanent damage to your vehicle.
Want to learn more about Allison transmission problems, check out the following articles:
