Why is My Transmission Slipping?

Automatic transmissions come in a wide variety of shapes, sizes, and designs.  The earliest automatic transmissions in automobiles only came in 2 speeds and varied the gear ratio based on fluid pressure.  Today automatic transmissions can have upwards of 8 or 9 speeds with many different ways of getting the power from the engine to the transmission.  Many of these new transmission designs are to help optimize engine efficiency by keeping the engine in a specific operating RPM to help meet stricter emissions requirements.

Even with the advent of newer more sophisticated transmission, the vast majority of the cars on the road today still operate with a torque converter driven automatic transmission that uses a planetary gear set and hydraulic pressure to operate.  For a quick overview of how a planetary gear set can provide different gear ratios in your transmission, check out this article from How Stuff Works on planetary gear sets.

If you suspect your automatic transmission is slipping, you need to first understand how power is transferred from your engine to your transmission.  Instead of having a clutch like a manual transmission, your automatic transmission has a torque converter.  This device transfers power from the engine to your transmission through a fluid pump.  The benefit of the torque converter is that if your vehicle comes to a stop, the torque converter will allow the engine to spin freely so your motor can idle.  The drawback is that the engine side of the torque converter always has to be spinning at least a little bit faster than the transmission side to continue pumping the fluid.  The slip you’re feeling in your transmission could simply be your torque converter transferring power to your transmission.

You can tell for sure when your transmission is slipping if you start to have hanging or slow shifts.  A hanging shift is when your transmission shifts much later than you anticipate it and seems to hang at a higher RPM before finally moving to the next gear.  You can tell this is happening by noticing your engine RPMs rising higher than usual during normal acceleration.

If find your transmission slipping, there could be a few different causes.  First, your transmission may be worn out.  The bands and clutches that cause gear changes may have gotten so worn that their friction surfaces have become smooth and are no longer holding this stationary when they should.  Unfortunately, you can only prove that this is the case by removing and taking apart your transmission.  Once you’ve gotten that far into it, you might as well simply rebuild it.  Another thing that may be causing your transmission slipping would be old or worn out transmission fluid.  The materials used to build a transmission are chosen specifically due to the way they interact with the transmission fluid used.  The wrong materials and fluids together will cause too much friction and hard shifts, or the opposite problem of low friction and sloppy shifts.

Over time your transmission fluid will lose some of its lubrication and friction modifying properties.  As these properties change, so will the shifting in your transmission which could lead to the problem you’re having.

Last, if you’ve got a low transmission fluid level it can slipping in your transmission.  Besides lubricating things, the fluid in your transmission provides hydraulic pressure to move the clutches and bands and cause the shifts to happen in your transmission.  If you’ve got a low fluid level, it can create a low pressure situation which can cause shifting problems.

If you find a low fluid level in your transmission make sure to top it off with the manufacturer’s recommend type of transmission fluid to make sure you don’t cause more problems.  Also, add BlueDevil Transmission Sealer with your top off fluid to restore the seals and gaskets in your transmission to stop any leaks to make sure you don’t end up with a low transmission fluid level again.

To learn more about BlueDevil Transmission Sealer and how it can keep your transmission running safely, click on the banner below!

BlueDevil Transmission Sealer

 

You can also purchase BlueDevil Transmission Sealer at any of our partnering local auto parts stores like:

  • AutoZone
  • Advance Auto Parts
  • Bennett Auto Supply
  • CarQuest Auto parts
  • NAPA Auto Parts
  • O’Reilly Auto Parts
  • Pep Boys
  • Fast Track
  • Bumper to Bumper Auto Parts Specialists
  • S&E Quick Lube Distributer
  • DYK Automotive

 

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6 responses to “Why is My Transmission Slipping?

  1. I only have a problem with slipping in my automatic 99 Mercedes c230 when the engine has just started and I put in gear and drive immediately. If I let it warm up for a few minutes and the engine revs down, I take off and it shifts properly and continues to shift properly. I can’t check the fluid on this vehicle because it has a sealed system with no dipstick. Any recommendations?

    1. Dave-

      Thank you for asking about your Mercedes c230. Based on your description, there a couple of different reasons why your transmission may be slipping. If you’ve got a low transmission fluid level it can slipping in your transmission. Besides lubricating things, the fluid in your transmission provides hydraulic pressure to move the clutches and bands and cause the shifts to happen in your transmission. If you’ve got a low fluid level, it can create a low pressure situation which can cause shifting problems. If you find a low fluid level in your transmission make sure to top it off with the manufacturer’s recommend type of transmission fluid to make sure you don’t cause more problems. Also, add BlueDevil Transmission Sealer, found here: http://store.gobdp.com/transmission-sealer-00236/, with your top off fluid to restore the seals and gaskets in your transmission to stop any leaks to make sure you don’t end up with a low transmission fluid level again.
      If this does not remedy the slip, you may want to bring the vehicle to a Transmission Specialist for a proper diagnosis.

      Thank you!

      -BDP

  2. So I have a 2002 Jeep Grand Cherokee Laredo (Automatic) and it is overall a great car, but my transmission has started to act up. In general it shifts really hard through all the gears unless it’s at the perfect rpms which I hate but I don’t know enough about it to fix the problem or even diagnose one. The bigger problem tho is when I come from a stop and cruise at 1000-1500 rmps it try’s to shift to second but it doesn’t go all the way there and then try’s to shift back to first gear and back to second and etc.. but when it does that it just bounces my car forward repeatedly until I step on the gas to bring it to 2500 rpms then it stops and shifts hard through the rest. I have always taken good care of this car with on schedule services and etc.. I am wondering if you can tell me if I need to look into getting a new transmission or if there is anything cheaper that could be the problem? Thank you, Yashin.

    1. Yahin,

      Thanks for your question about your Jeep Grand Cherokee. Based on your description it does sound like your transmission may need a rebuild. Unfortunately, there isn’t much you can do as an owner besides checking your transmission fluid and level and condition there isn’t much you can do. If you find a dirty or burnt smelling transmission fluid you may try changing your transmission fluid to get it back to shifting normally. If you find a low fluid level you can use BlueDevil Transmission Sealer (available here: http://store.gobdp.com/transmission-sealer-00236/) to seal the leak and then top off your transmission to see if more fluid will get it back to shifting normally.

      Besides that you’re best bet at figuring out what’s wrong is taking your jeep to a transmission specialist or a Jeep dealership for diagnosis.

      Thanks again for your question!
      -BD Auto Pro

  3. Hello, I recently had my 2003 Jeep Grand Cherokee worked on for a loud metallic tapping noise that got faster and louder the faster you drove. Thankfully it ended up being just a loose rocker arm, but while the mechanic had it, he did an oil change and rear brake pads. The day I picked it up, I noticed it shifted hard from 1st to 2nd gear, and slipped from 2nd to 3rd! It was not doing this before he worked on it. I thought it may just be low on trans fluid, but when I checked it, it was about 3-4 ” over the “full” dot and slightly bubbly. I contacted the mechanic and told him this, and he said I need to check it while its in neutral, and acted like I was stupid. I may be a woman, but I DO know how to check the fluids in a vehicle, as I have always driven 2nd-hand vehicles that have always had some kind of issue! Well, I checked it again with the parking brake on and in neutral, it seems the fluid level is not a high as when it was in park, only a 1/2″, but still kind of bubbly looking…and it is still shifting hard and slipping. Any ideas on what could be going on? I would soooo appreciate your feedback!
    Thanks, Amy

    1. Amy-

      Thank you for asking about your Jeep Grand Cherokee. Based on your description, we recommend changing your transmission fluid and refilling the system with fresh, clean fluid. The system may have gotten an air pocket stuck in the system, which would explain the slight bubbling you are seeing. Changing the transmission fluid should correct this issue. If not, you may want to bring the vehicle to a transmission specialist for a better diagnosis.

      Thank you!

      -BDP

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