Hey everyone. I just bought a 2000 impala with 80k miles and I got some questions about the trans. Now I could be way off base here, but i thought most automatic trannys have two overdrive modes. The first is the standard overdrive, and then after gaining even more speed the RPM will drop again into another stage of overdrive. I've heard people call this "lock" gear. Am I right about this?

Anyways, sometimes the trans slips when going from overdrive into lock. Every other gear shifts fine with no slippage, its just this 2nd overdrive stage. Unfortunately my impala has no tac so I can't see the RPM shoot up, but I can hear it and feel the loss of power for a quick second. It still goes into this final gear and stays, just slips into it.

The second thing is that sometimes the trans will shift into all gears pretty hard, but this only comes and goes. I'm not sure when/if the previous owner changed the trans fluid and filter, so I plan on doing that first. Any chance that would help?

Again, most of the time the trans is fine, i'm just worried these might be "warning signs" of problems and I'd like to have less expensive repairs instead of waiting until the whole thing fails. Considering these 2 things, could it possibly be an inexpensive repair, or would it need a full rebuild either way?

Thanks.

 

In the 4-speed OD transmission, there is only ONE OD gear, which is the 4th gear in the sequence. The "other" thing you're feeling is not an additional "gear", but the torque converter lock-up clutch engaging. Same gear ratio, just no torque converter slippage.

Mine seems to have a slow engagement at highway speeds, plus when I tap the brake with the cruise control, a slight flare in engine rpm happens. Nothing really abnormal, just different than some other cars I've driven over the years.

NTX5467