'96 Lumina Shifting Problems.

[Uncouth]

Hi guys, I was wondering if you could help me out!?


I have a '96 Chevy Lumina Automatic, and here recently it hasn't been shifting gears like it's suppose to. I'll get going, get up to 30mph and then the RPM's just keep climbing, every once in a while it will kick itself out of it and then other times I have to pull to the side of the road, shut it off, then turn it back on and it's back to normal. So I just wanted to know if you guys know what would be causing this problem and how I could fix it.

Thanks in advance Gentlemen.

[Schurkey]

Originally Posted by Uncouth

Hi guys, I was wondering if you could help me out!?


I have a '96 Chevy Lumina Automatic, and here recently it hasn't been shifting gears like it's suppose to. I'll get going, get up to 30mph and then the RPM's just keep climbing, every once in a while it will kick itself out of it and then other times I have to pull to the side of the road, shut it off, then turn it back on and it's back to normal. So I just wanted to know if you guys know what would be causing this problem and how I could fix it.

Thanks in advance Gentlemen.

Is the fluid level correct?

When was the last fluid change INCLUDING FILTER? (not just some bozo using a "fluid exchange" machine.)

[jeffcoslacker]

Noticed any idle speed strangeness at all? Like idling too high, fighting the brakes, or trying to pull itself along at 30-35 mph without your foot on the gas, any of that?

[Uncouth]

Originally Posted by Schurkey

Is the fluid level correct?

When was the last fluid change INCLUDING FILTER? (not just some bozo using a "fluid exchange" machine.)

I'm not exactly sure when the last time the fluid was changes. The last stuff my Dad put in the Car was Transmission fluid. My Dad knows about Cars but he works to many hours to do it so I've put it on myself.

Noticed any idle speed strangeness at all? Like idling too high, fighting the brakes, or trying to pull itself along at 30-35 mph without your foot on the gas, any of that?

No, when it idles it actually almost feels like it turned off. No fighting the brakes and no it doesn't pull me along, I let off the gas and it slows down.

[jeffcoslacker]

OK, was just making sure it wasn't the throttle position sensor...that will make it hang and not upshift because the ECM is not understanding the load the car is under, getting invalid throttle opening readings. It's a very easy and cheap fix so I was hoping you'd say yes, you'd noticed other problems. I tried

Otherwise it sounds like you have a shift solenoid that is failing or the ECM is not controlling the tranny right, and you're resetting the fault by restarting it. But I'd lean toward a solenoid.

Also you have a vacuum modulator on that, they can cause hanging upshifts too, but your description of the nature of it says this isn't the problem...typically if it was sucking air the rpms would climb and you'd have to smack the gas and drop it suddenly to get an upshift, and shutting down and restarting would have no effect...you've got an electrical component or logic control issue, most likely.

[jeffcoslacker]

I think just for fun before getting too far into it, I'd unplug, inspect and spray contact cleaner into all harness connections going to the tranny, and clean up any tranny or engine ground points you see....

[jeffcoslacker]

I guess it's possible it could be overfull and is aerating the fluid so badly it can't develop enough pressure to change gears...that's a long shot though, but check level anyway. Fully warmed up, in PARK, idling.

[Uncouth]

Ok cool man, I'll give those a shot and update you on the situation later.