Transmission slipping on 2005 Chevy Impala

I have a 2005 Chevy Impala (71,000 miles, 3400 engine) that has an initial slip in the transmission when accelerating from a stop. As you take your foot off the brake and step on the accelerator, the transmission hesitates, then kicks in with a sudden, stiff clunk. Subsequent gear changes and acceleration are normal. This always happens after the car has warmed up for 5 or 10 minutes, and can be avoided if you are VERY careful and step GENTLY on the accelerator. There was no noticeable metal in the transmission fluid, but I changed it anyway, to no avail. The car gets very good gas mileage and otherwise runs well. Any advice?

I would get this car into a good transmission shop ASAP, before more damage is done. Has the fluid and filter been changed recently? What color is the present fluid? You will require at least a fluid change.

Has this Impala done this from when new, or has this issue started later on in life? If yes, about when…time/mileage?

I bought the vehicle new, and it never did this until just recently (at about 70,500 miles). There was no evidence of metal in the original transmission fluid, but it was somewhat dirty, so I had it changed out to see if that would help. The new fluid has been in for several weeks now (about 500 miles). It appears clean and clear red, but didn’t help with the slippage. Again, no visual evidence of any metal contamination. The vehicle has been well maintained, with all scheduled servicing. It has never been used to tow anything, and until now, has given good service as a typical suburban family sedan. Thanks.

How often has the fluid been changed? Was the transmission doing this before the last change at 70,500 mi?? or did it start after? This sounds like a pumping problem.


I had never changed the transmission fluid until this started happening. The shifting was normal until about 70,500 miles.

This is a hard way to learn this lesson, but nevertheless, you should now be aware that trans fluid (and filter) need to be changed every 3 yrs or 30k miles, whichever comes first. When this schedule is not followed, trans failure can take place any time after ~90k miles, and is pretty much of a sure thing by 125k miles.

While your experience of trans failure at 70k miles is unusual, it is likely that fluid changes at 30k and 60k could have prevented this early failure. I’m confident that you will maintain your next transmission much better!

Anyway–as was said, you need to get the car to an independent trans shop right away.
Every time that you drive the car in this condition, you are increasing the potential repair costs.