Gears slipping

After a few miles of driving or idling when the car gets warmed up, it won’t stay in, or go into gear. If I put it in neutral as I’m driving, turn the ignition off and back on again it goes back in gear for a little bit, then starts all over. Every time I restart the engine it works temporarily. I thought it may be the gasket, but cant figure out why restarting the engine would make it work again

My car has 209000 miles.
My car has an automatic transmission.

Experienced mechanics share their insights in answering this question :
Hi there. This can be caused by a problem with the valve body in the transmission or maybe the start of a serious engine failure. When you start the vehicle, it will cause the circuits to reset in the valve body which can cause it to start working fine again. But if there is too much clearance in the transmission, then that can cause it to start acting up again.

I usually drain the fluid from the transmission pan first and inspect it. If there is metal or a lot of clutch material in it then I replace the transmission. If the fluid is fine and clean, then I replace the valve body.

I would also check for codes first just to be sure that it is not an electrical issue. If you want to have this shifting problem checked, consider YourMechanic, as a certified mechanic can come to your home or office to diagnose why the transmission is not shifting right.

How to Identify and Fix Common car Problems ?

Our sources include academic articles, blog posts, and personal essays from experienced mechanics :

In an automatic transmission, slipping can be caused by wear and tear on numerous different parts. These include damaged or worn clutch plates, transmission bands, and solenoid packs. If your automatic transmission has been slipping, it`s likely a technician will replace some or all of these parts to fix the problem.
The Transmission Range Sensor tells the PCM the position of the transmission shifter. The PCM uses this information to control which gears of the transmission to enable or disable. When the TR sensor fails it can cause wrong gear starts, no upshifts, or what feels like a falling-out-of-gear condition.
What is the fix for a slipping transmission? It`s simple. Just pop the hood of your vehicle, locate the transmission switch, and change the setting from “SLIP” to “STABLE” . . . If only it were that easy.
A slipping transmission means that it is struggling to shift between gears and/or stay in gear. It could be the sign of a major transmission problem or you may just need minor transmission maintenance.
a problem with one or more of the solenoids can cause a lack of pressure, resulting in hard, soft or delayed shifts. a failed shift solenoid can also cause transmission slippage, where your engine revs faster but the car stays at the same speed.
For example, in some situations an oxygen sensor can cause poor shifting in your transmission – if the engine isn`t running correctly, the transmission control module may misinterpret when and where it`s supposed to be shifting, causing erratic behavior at the transmission.
Transmission slipping can be dangerous, and can easily lead to accidents, or further damage to your transmission. Get your car check out by a mechanic right away if you`re experiencing this issue.
Issues That Can Happen From Having a Bad Transmission

In some of the most extreme cases, you will not be able to give the car any gas, which means you may slow down and this can cause problems when trying to continue going, especially on a highway or major road.

Shifting Issues

When the transmission fluid isn`t clean or is blocked by a clogged filter, the internal components won`t have the lubrication they require to function properly. This could lead to shifting issues, grinding gears, slipping transmission or other common symptoms of transmission problems.

Along with gear slippage, low transmission fluid levels can also cause low levels of pressure, which leads to slower engagement when shifting gears. If you notice your transmission takes a second to engage when put into drive or reverse, it could be due to low fluid levels.
This is actually a really good question—low engine oil, as a general rule, won`t cause transmission problems but it can damage your engine, so you should check it regularly.
Maintain Proper Transmission Fluid Levels

The #1 cause of transmission failure is low fluid, which causes overheating. In automatic transmissions, it causes delayed engagement, harsh shifts, and slippage.

While not necessarily a sign of oncoming major transmission failure, slipping does indicate that your transmission is in serious need of service and repair. To leave it unchecked is to put both your vehicle and yourself, as well as other drivers and pedestrians, in danger.

Relevant Questions and Answers :

the most relevant questions and answers related to your specific issue

My clutch went from a slip in one gear to all 6 gears to sticking to the floor all in under 3 hours of non consecutive driving.
ANSWER : Hi there, thanks for writing in. It’s entirely possible that a component failed. For instance, if the clutch pressure plate failed, then the clutch pedal will feel very spongy and can cause the car to slip and be very difficult to shift. If it has a dampened flywheel, and that fails, then the car may lose the ability to go anywhere. It will go into gear fine, but will not move forward. If a clutch release lever failed, it may no longer release the clutch enough to allow gear changes, though slipping would be minimal. A failing hydraulic component could also cause the clutch to fail very quickly. Based on the symptoms, I think that the pressure plate has failed, but it’s impossible to say for sure without seeing the car in person. You should have a qualified technician, such as one from YourMechanic, inspect your car and diagnose your clutch issue.

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My manual car won’t go into gear, it turns on and the clutch goes down perfectly fine. It happened after my gears grinded, the car
ANSWER : If the clutch mechanism is releasing properly, and the shift linkage is not malfunctioning, your transmission will have to be removed from the vehicle and inspected. Once a transmission has been removed from a vehicle, if the problem is a broken or worn part or parts, and the transmission has 100,000 miles or more, the most cost effective approach is to just simply rebuild the whole transmission. There are transmission rebuild kits that are sold just for this purpose. Rebuilding a transmission is no big deal and is indeed easier in many respects than rebuilding an engine. You can rebuild your transmission right in your own garage. You can NOT rebuild an engine in your own garage due to the highly specialized, and extremely costly, machine shop equipment required. Occasionally, mobile mechanics will take on a transmission rebuild job especially as once the mechanic removes the transmission from the vehicle, it is just simply a modular unit that can be easily transported to a mechanic’s shop and rebuilt right there and then returned to your vehicle. If you have further questions or concerns, do not hesitate to re-contact YourMechanic as we are always here to help you.

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Loose gearbox that won’t find 2nd or 5th gear, sometimes hard to differentiate between 1st and 3rd.
ANSWER : There are a couple of possibilities. The first thing that comes to mind is of course the shifter itself. There is a nylon ball and socket joint at the base of the gearshift lever that sometimes falls apart, making the feel of the shifter very vague. Additionally, there are links to the transmission shift linkage that involve nylon bushings and joints that can fall apart. Both problems are very common on your car. The other less common possibility is that you have a bad motor mount that is allowing the transmission to move around too much when you try to shift gears. either way, it’s not a big deal to fix, and probably won’t require expensive transmission work. If you contact Your Mechanic, they can send a technician to your home or office to check out you shifting issue and let you know what repairs it will take to correct it.

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My manual gear box is starting to get a little bit "clunky" as i change gears, is there an additive i can add to the gear oil?
ANSWER : The first thing to do is to drain and check the oil to see if it has any broken chunks of metal or a lot of brass metal pieces that indicate the gears and synchronizers for the gears are bad. If no metal is found then replace oil with recommended oils for transmission. If metal is found then an internal transmission repair is needed.

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Gear Shuffling Problem in Vauxhall Vectra 52 Registration
ANSWER : Hi there. We don’t see a lot of Vauxhall Vectra’s here in the United States, so unfortunately, we’re not able to suggest a possible solution or cause of this problem you’re experiencing. You should consult with a professional mechanic in your home town to determine what’s causing the shifting problem you’re experiencing.

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Sifter floats from gear to gear and when letting out the clutch there is no response.
ANSWER : Hi there. Either the clutch has failed causing the transmission not to engage in any gear, or the transmission shifter plastic rings broke and will not engage the shifter. Check the clutch and make sure that it is moving when the pedal is pressed down. If the fork on the bell housing is moving and the wheels can be moved when the clutch pedal is depressed and then the wheels not moving when the pedal is let up, then the clutch should be in an okay shape. Most likely the plastic rings on the shifter housing has broke and making the shifter move around. If you need further assistance with the shifter moving around too much, then seek out a professional, such as one from YourMechanic, to help you.

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Second gear misshifts when I drive, all other gears are fine.
ANSWER : Hello.

A transmission coming out of gear is most often caused by worn transmission components. It may be possible that the synchronizer rings, which are meant to smoothly mesh the gears inside of the transmission, have worn out and are no longer able to stay in gear.

It may also be possible that the gears themselves have worn out, and can no longer hold the torque of the engine. This is usually preceded or accompanied by a grinding noise when attempting to shift into that gear. If this is the case, it may be possible that the transmission may need to be rebuilt.

As transmission rebuilds can be expensive, I would recommend having the vehicle diagnosed by a professional technician who specializes in transmission, to determine if a rebuild is required.

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My truck won’t allow me to change gears even when pressing the clutch. No gears go in at all. Makes it impossible to drive.
ANSWER : Hello, this concern is possibly the slave or clutch master cylinder failure. These two components use brake fluid to apply pressure for movement of the clutch system. This fluid breaks down in time and causes the seals to fail (leak). A low fluid level would cause this concern as well as internal leakage. Replacement of components would be necessary. This type of concern would need to be inspected. If you’d like, a certified technician from YourMechanic can come to your location to diagnose your vehicle, and possibly replace your clutch master cylinder if need be.

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