Skip the auto shop - Our mechanics make house calls

Q: Why is my transmission slipping?

asked by on

Very disappointed that the automatic transmission in my 2006 GMC Sierra began slipping after just 58k miles. This truck gets used pretty consistently, but at around 49k the transmission began slipping just a little, figured the truck was showing its age. Now the truck is not drivable, might as well put it in neutral! Is this something I can get repaired or is the whole transmission going to need replacing? I would like to fix this problem so it does not happen again.

The transmission in your truck has the updated 4L60 series with a heavier duty forward gears and thrust bearings so your transmission problem is most likely the torque converter or front pump failure. The clutch materials in an automatic transmission are very thin and if you have had slipping for over 10k miles you may have caused even more internal damage to other internal components. You will most likely need to have the transmission replaced or overhauled with a new torque converter. All the lines will need to be flushed out also to keep from contaminating the new or rebuilt transmission. Replacing the transmission with a remanufactured or a good used transmission with a warranty would be the recommendation I would give, since the truck is under 10 years old and has low mileage. Have the transmission system thoroughly checked by a certified mechanic, such as one with YourMechanic, before condemning it and before any replacements or repairs are done.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Ask a Mechanic
(100% Free)

Have a car question? Get free advice from our top-rated mechanics.

Ask A Mechanic
Over 10,000 questions answered!
  1. Home
  2. Questions
  3. Why is my transmission slipping?

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: Transmission temperature keeps going on and transmission slips

When the clutches inside the transmission are slipping, it will heat the transmission fluid up until you get the overheat light on. You will need to have the transmission pressure tested by a transmission mechanic to diagnose the slipping. The...

Q: Truck stalled and won't turn over.

This sounds to me like a classic fuel pump failure, I would have a certified mechanic inspect your fuel pressure. If the fuel pump is fine, check for voltage at the fuel pump relay. If these aren't the problem check...

Q: will a 98 chevy astrovan fuil pump fit my 90 gmc seirra 4x4 i think thay both have a 350

Different (non interchangeable) fuel pumps were used on the two vehicles that you are inquiring about. If you are looking for a used fuel pump for your 1990 Sierra, please simply search at Car-Part.com you will find an exact match...

Related articles

How Long Does a Distributor O Ring Last?
The distributor is part of the ignition system in your vehicle and its purpose is to route high voltage from the ignition coil to the spark plug. The spark plug then...
P0052 OBD-II Trouble Code: HO2S Heater Control Circuit High (Bank 2 Sensor 1)
P0052 code definition HO2S Heater Control Circuit High (Bank 2 Sensor 1) What the...
P0240 OBD-II Trouble Code: Turbocharger Boost Sensor B Circuit Range/Performance
P0240 code definition Turbocharger Boost Sensor B Circuit Range/Performance What the P0240 code means P0240 is an OBD-II generic code triggered when the Engine Control Module (ECM) detects the intake boost...