Transmission leaking

My cars reverse stopped working yesterday I checked the oil it was running low so I laid for a oil change and for them to put transmission fluid and it keeps making this noise like there's rocks getting tossed inside the hood. The mechanic told me that there was oil that was leaking and that was what might have caused the reverse to stop working but when he test drove it he said that my car needed a new transmission

My car has 335789 miles.
My car has an automatic transmission.

Experienced mechanics share their insights in answering this question :
Hi There,
It sounds like you may have a transmission fluid leak. What you are describing is often a sign of low transmission fluid or a faulty transmission control solenoid. As you know, automatic transmissions use pressurized hydraulic fluid to change gears. Every time a gear change is required, the car’s computer activates a transmission solenoid, which directs transmission fluid into the valve body to engage the correct gear. When this is faulty or not working properly, this can cause a delay in gear shifting or in some cases cause the car to not shift at all. This type of problem is amplified any time the transmission is low on fluid creating a drop in hydraulic pressure. I would recommend having a professional from YourMechanic come to your location to diagnose and inspect your vehicle.

How to Identify and Fix Common car Problems ?

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

A transmission leak is a common occurrence that happens through excessive wear over time. The plugs could be loose or the pan could be punctured. Either way, the moment you notice transmission fluid, contact your local mechanic and have them inspect and repair your transmission fluid leak.
The Problem: In these cars, a shift cable could wear out over time, resulting in a mismatch of the gear position indicated by the shift lever, according to GM. If the cable fractures, the driver may not be able to shift gears, remove the key from the ignition or shift the transmission into Park.
Faulty Transmission Pan or Gasket

The fuel pan gasket is the number one culprit if your vehicle`s transmission fluid leaks when your car is parked. Cars with automatic transmissions have a pan gasket designed to catch most fluids leaking from the engine.

One of the main causes of transmission leaks is a cracked pan gasket. When there is some kind of fray in the gasket, you`ll need to replace it, as the fluid inside will continue to seep out. This cause is easy to fix. All you`ll need to do is purchase a new gasket (which is relatively inexpensive).
A transmission leak will not get better on its own. If it goes unchecked, vehicle operation will eventually be affected, and you may find yourself with an expensive repair. So, while it may be safe to drive with a leaking transmission, it`s not advisable, and you shouldn`t put off fixing the problem.
How Much do Transmission Leaks Cost to Repair? The cost to fix a transmission fluid leak in a vehicle can be as little as $150 to replace a seal and around $1,000 to for a new torque converter.
Some common symptoms of a failing transmission include unusual noises, slipping, grinding, and jerking when engaging and shifting gears. A failing transmission can lead to various issues ranging from your vehicle making loud noises, behaving erratically on the road, or being undrivable.
As soon as you notice your car is leaking transmission fluid, you should seek to contact a certified mechanic, such as on from YourMechanic, to have your transmission fluid serviced. The faster you get the leak fixed, the less problems you will have with your vehicle in the future.
How Can You Spot a Transmission Leak? One of the cleaerest signs of a transmission leak is that glaring puddle of transmission fluid underneath your car. You can tell transmission fluid from other potential leaks by its color and consistency; it tends to be red and slippery with an oily smell.
When the torque converter starts malfunctioning, you may feel shuddering and even slipping in overdrive. You usually notice your car shuddering because it feels like it`s vibrating. Your car will vibrate even when you`re not going very fast. The shuddering makes the car lag and is very noticeable.
One of the most obvious signs that you are probably low on transmission fluid is when you notice a fluid leak under your vehicle. Transmission fluid is typically a bright red color, so it is fairly easy to identify compared to engine oil, transmission coolant or brake fluid.
Adding a bottle of one One Seal Stop Leak or Transmission Seal Stop Leak products is often all it takes to seal your leak. Then all you have to do is check your transmission fluid level.
One of the most obvious signs that you are probably low on transmission fluid is when you notice a fluid leak under your vehicle. Transmission fluid is typically a bright red color, so it is fairly easy to identify compared to engine oil, transmission coolant or brake fluid.

Relevant Questions and Answers :

the most relevant questions and answers related to your specific issue

1998 mercedes benz c280 transmission fluid leak from top
ANSWER : Hi there. Unfortunately, we are not able to receive pictures or video to pinpoint damage or identify parts for vehicles through this platform. The best way to identify this item is to search online for a detailed schematic of your C280 Mercedes-Benz or contact a local MB specialist mechanic or the dealership service department to determine the parts name and function. You might also want to have a MB specialist mechanic install and inspect your vehicle for further transmission fluid leaks to ensure the repairs are correctly completed.

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Will adding Transmission Fluid with Stop Leak to a transmission with over 230,000 miles hurt it?
ANSWER : Both of these additives are designed to block small leaks or seepage from a gasket or rubber seal an not to fix major leaks or leaks where there will be excessive pressures, such as coolant leaks into the combustion chamber of the cooling system or leaks in high pressure areas of the transmission.

I would not recommend the use of these products unless a manufacturer specified to use them, like how GM did on their earlier models of the modular motors that had coolant leaking through the pores of the engine block from defective castings.

Before adding any of these additives I would recommend having a mechanic check the transmission fluid leak to see what the proper repair should be. These additives can sometimes clog systems and make matters worse in the long run.

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Transmission additive to stop pump seal leak I don’t want to spend $750 on repairs will a transmission stop leak fix it
ANSWER : You can certainly use transmission stop leak, however depending on how bad the leak is or the amount of pressure coming from the leak, this may be only a temporary fix. I would suggest having a professional from YourMechanic come to your location to take a look at the vehicle.

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There is automatic transmission fluid in a manual transmission. Is it okay to leave or do I need manual transmission fluid?
ANSWER : This would depend on what the manufacturer recommends. Many manual transmissions do take automatic transmission fluid. If your transmission has ATF in it, it is very likely that it is supposed to have that in there. If not, it is likely that the transmission would not function properly with the wrong fluid. Many manual transmissions will also take engine oil as a lubricant. The best way to know for sure is to check your owner’s manual or call your local General Motors dealership to inquire.

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My car is leaking transmission fluid – I can’t diagnose the leak
ANSWER : Based on the NHTSA database covering consumer complaints, as well as government mandated recalls and factory service bulletins, for your specific year, make and model, I do not see evidence of widespread complaints about transmission fluid leaks. Such leaks are, in fact, common in transmissions made by any car company, particularly if the transmission is older than say 10 years. There is a manual shaft seal, oil pan gasket, output shaft seals, case seals, torque converter seal (inaccessible) and so forth all of which are potential leak points on your transmission.

If you want to identify and resolve these leaks, certainly a certified Mechanic from YourMechanic could come out and perform a transmission leak inspection and let you know where the leak points are and what it will cost to resolve them.

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’98 Dakota 2wd-rear..with Air. Oil leaking in back of engine and above tranny. Leak is right around d-cap and a sensor post.
ANSWER : Hi there. It’s quite possible that this is a rear oil seal or oil pan gasket that is leaking; or perhaps a transmission oil tube seal that is leaking. The problem with trying to diagnose an oil leak is that typically the oil tends to spray onto different components underneath the vehicle. You might want to have a professional mechanic complete an oil leak inspection to help you locate the source of the leak and recommend the right repairs.

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My 1993 Ford f-150 is leaking transmission fluid from the rear end of the pan. ive already replaced the gasket as well as the pan
ANSWER : There are two different places it may be leaking if not from a cracked housing at one of the pan bolt holes. The rear tail shaft housing or the shift linkage shaft seal could be leaking. Have the areas cleaned and vehicle run on a lift to isolate where it is coming from.

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Can my antifreeze leak be linked to my transmission problem?
ANSWER : Hi there. You will need to first find the coolant leak and address the leak and get it fixed. The engine may overheat and cause even more problems. The transmission or engine misfires could be from the coolant leak if the coolant is getting onto the wiring of the engine. You may also be going into failure mode if the engine is running hot. Have the cooling system diagnosed and repaired first and any coolant leaks on the harnesses cleaned of coolant that may have got in connections. Then scan and test systems for further problems and diagnosis needed.

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