Like my dad, I prefer vehicles that offer a manual transmission because they make for a more engaging driving experience.
But I also can’t ignore the convenience of an automatic transmission.
Even the modern automatic in sports cars are developed to shift much faster than anyone can.
I’ve owned my fair share of older high mileage vehicles with manual and automatic transmissions. And I can tell you from experience fixing a manual transmission is way cheaper than fixing an automatic transmission.
Let’s look at some specific issues with the transmission that could be causing your car to jerk when shifting from Park to Drive.
Why the Transmission Jerks When You Shift
If your car jerks when shifting from Park to Drive, it’s an indication of underlying issues in the driveline.
Anytime your car lunges or jerks after shifting the transmission, the problem could be due to:
- Mechanical gears that aren’t aligning properly. This can result from loose or otherwise worn-out components like the driveshaft and input/output shafts.
- Hard shifts may also be due to low transmission fluid; maybe it’s your car’s way of telling you it’s time for a transmission fluid service.
- It could also be the sign of failed sensors and faulty components.
Whatever the cause of hard shifts from Park to Drive. By the time you start noticing issues your transmission very likely will need to be repaired by a professional mechanic.
And the cost will depend on the problem. But a good mechanic will be able to diagnose and fix the issue.
How an Automatic Transmission Works
A car with an automatic transmission that jerks when shifting from Park to Drive is enough to make anyone feel anxious that something serious is wrong.
Let’s face it, when automatic transmissions start to go bad you can expect that it’s going to be an expensive fix.
In a car with an automatic transmission the torque converter connects the transmission to the engine. It replaces the friction clutch in a manual transmission allowing the vehicle to come to a complete stop without stalling.
The torque converter uses pressurized fluid to transfer power to the gears.
Issues with the Torque Converter
A damaged fin or bearing in the torque converter can lead to hesitation when shifting the transmission.
The transmission may even slip out of gear as you’re driving, which can happen in both automatic as well as manual transmissions.
This is usually due to a worn-out clutch.
In an automatic transmission this is because the engine torque isn’t efficiently converted into the hydraulic pressure needed to shift gears.
A rough shifting transmission is a good sign of torque converter issues.
The Importance of Transmission Fluid
Transmission fluid is a type of reddish black oil used to lubricate, clean and keep moving parts of the transmission cool.
An automatic transmission is a system with many moving parts with some running concurrently with others.
To make sure everything engages and disengages smoothly transmission fluid aids in lubrication of parts.
To do its job transmission fluid must be at the right level (keep reading to find out how to check the transmission fluid level).
An automatic transmission is a closed system. The only major way for the fluid to become low is if there’s a leak in the system.
Given the scope of its job, transmission fluid can become dirty overtime.
And if not replaced routinely, it can cause issues like a transmission that jerks when shifting from Park to Drive.
Low Transmission Fluid Can Cause Hard Shifts
Low or burnt transmission fluid can cause the overheating of a transmission, and a deficiency in the creation of hydraulic pressure needed to engage gears.
Like most systems in a car the transmission is a sealed system. This means that low transmission fluid is usually due to a leak somewhere.
Burnt transmission fluid smells a lot like burnt toast – it will even look burnt.
Burnt fluid results from an overheated transmission caused by lack of maintenance.
Once the fluid is burnt, you’re looking at buying a new transmission.
Contaminated Transmission Fluid
Dirty transmission fluid will lead to your car jerking or lurching when shifting from Park to Drive.
Contaminants and foreign materials compromise the integrity of the fluid while causing transmission components to wear out prematurely.
If there are no obvious signs of a transmission leak. But your car hesitates to go into gears. This is a possible sign of contaminated transmission fluid.
The popular advice from auto manufacturers these days is that transmissions are filled with lifetime fluid, so you never have to worry about maintaining your transmission.
This is absurd.
Regular transmission maintenance regardless of how new your car is will prevent against issues like contaminated transmission fluid.
How to Check Transmission Fluid
With all the transmission issues I’ve suffered, I know how to check transmission fluid. It’s as easy as checking oil levels:
- Take out the dipstick marked for the transmission.
- Wipe it with a clean rag or paper towel.
- Put it back into the transmission fill tube.
- Then check the fluid level against the markings near the end of the dipstick.
If it’s low, you know you need more transmission fluid. It’s not a bad idea to take your car to a mechanic you trust to see if there might be a leak.
This is also a good time to check to see if the fluid is burnt – healthy transmission fluid is red and translucent.
A Clogged Transmission Filter Can Make Your Car Jerk When Shifting from Park to Drive
Did you know that your automatic transmission has a filter?
And like other filters around your car if it gets clogged the transmission can’t shift smoothly.
As an added layer of preventative maintenance. Replace the transmission filter every time you change the transmission fluid.
Hard Shifting Could Also Be the Result of Transmission Pump Failure
Inadequate fluid transfer could be the culprit behind a jerky transmission.
If a transmission that jerks when shifted into gear is followed by a check engine light. This could be signs of issues with a weak or failing transmission pump.
The culprit is unfiltered debris or contaminated transmission fluid that forces the pump to work harder than it should leading to premature wear and tear.
Worn Transmission Components
This is what happened to the transmissions in older cars that I’ve owned.
Specifically, this issue happened with a 1993 Mazda 929 and 1996 Buick Rivera.
Both cars had way over 150,000 miles – if memory serves the 929 was in the 220,000-mile range. And by the time I got these cars they were well over a decade old.
Though the engines were strong. The transmissions were rendered weak after years of service – transmission parts simply needed replacing.
Driving with a Jerky Transmission
A transmission that’s operating normally will move seamlessly from one gear to another.
The transmissions in modern cars are so smooth you don’t even notice when its changing gears.
You could drive a car with a transmission that jerks when shifting from Park to Drive or an otherwise bad transmission. I drove the 929 for months with a bad transmission while I saved up money to get it replaced.
I don’t recommend, though.
Driving a car with a bad transmission will not only likely cause damage to other parts. But fuel economy will be awful as it was for me.
And you risk a higher repair bill when you eventually get it fixed as also happened to me.