Auto Shifting Problems

My girlfriend has a 99 Camry that’s having problems with shifting. It’s an automatic with an I4. The speedometer is not working properly also. I noticed that when the speedometer is not functioning properly is when the tranny is not shifting at all or is shifting back and forth from one gear to the next. Like I just mentioned, the tranny will not shift (engine will rev real high) or it will continually shift back and forth. When it won’t shift at all the speedometer will not being displaying any speed when the car is actually moving 20 or 30 mph. When it shifts back and forward the speedometer will displaying a speed that is actually incorrect and is varying a lot.
Does the tranny use the speedometer to help determine which gear to run in? If anyone knows what could be the problem here I would appreciate the help.
Thanks,
Paul

My girlfriend has a 99 Camry that’s having problems with shifting. It’s an automatic with an I4. The speedometer is not working properly also. I noticed that when the speedometer is not functioning properly is when the tranny is not shifting at all or is shifting back and forth from one gear to the next. Like I just mentioned, the tranny will not shift (engine will rev real high) or it will continually shift back and forth. When it won’t shift at all the speedometer will not being displaying any speed when the car is actually moving 20 or 30 mph. When it shifts back and forward the speedometer will displaying a speed that is actually incorrect and is varying a lot.
Does the tranny use the speedometer to help determine which gear to run in? If anyone knows what could be the problem here I would appreciate the help.
Thanks,
Paul

3 things to check:

1. Tranny fluid level when cold (before you start the car).
2. Condition of fluid (red=good brown=bad)
3. Speedo cable - Might be broken or damaged.

If the fluid level checks Ok but it's brown, get a tranny flush & fill with a new tranny filter. Also check the speedo cable.

Good luck...

I don't think there is anything to do with the transmission fluid. And I am not sure if your car still use cable for the speedometer, most cars use electronics already. It's probably the speed sensor. The sensor feed the data into the computer that controls the transmission. So, if the speed is not sensed right, of course the computer can't tell the transmission when to shift.

Ooops! I forgot to mention. I have already replaced the tranny fluid and filter. The fluid was a dark dark redish brown color. Not good huh? How does the flush and fill work? Flush it with new fluid a time or two then fill with new fluid? Replacing the fluid and filter made no difference.
I haven't priced a speed sensor yet. I'll do that today. Thanks for ya'lls help and if the is anymore advice anyone has I would appericate it. Thanks again.

I suspect that the output speed sensor is bad. There are 2 speed sensors for automatic transmissions. One is the input speed sensor, but the one that causes your speedometer to work is the output speed sensor. However, if your car has ABS, this sensor can be faulty and the tranny will still work. My guess is you don't have ABS.

There should be a fault code set so have the faults read at autozone for free to confirm it.