Help ! transmission cycling


#1

HI,



I have this 1997 Mazda protege, 4 speed auto transmission with 81K miles on it. yesterday a weird problem showed up. The car seems to jump into 3rd gear spontaneously, even though I am applying gas only to cruise at around 55-60mph. If I back of the gas almost completely, it goes to 4th gear but now starts loosing power and slows down. If I try to speed up, goes into 3rd gear, accelerates and drops to 4th gear for cruising and then again jumps into 3rd, and the cycle repeats. all this I can tell for the tachometer and engine reving noise.



this has never happened before and I am scared its something serious. The Transmission fluid on this car was changed at around 62K, and fuel injection also cleaned around 60K.



Any ideas please ! Thanks


#2

Have you CHECKED the transmission fluid level recently? That’s the first thing to do. Your post says the fluid was changed about 20K miles ago, but doesn’t say you’ve checked it since then. The engine must be running when you check it, so don’t get caught in the moving belts.


#3

Forgot to mention, there is no check engine light. Also on some days car does not start in the morning unless gas is applied for a while. dont know if its related


#4

That’s a second problem. The car should start when you turn the key, and not require you to do anything with the throttle. I don’t think these two issues are related, but on a computerized vehicle almost anything is possible.


#5

I checked trans fluid when car was off. level was fine and so was appearance - my friend suggested wiping the dipstick with white paper towel, and see the color, it appeared pinkish. I will try when the engine is on. Does it need to be driven before checking this ?


#6

You did get a false reading when you checked the fluid level while the engine was off. When the engine’s running, check the dipstick and it will have a cold full mark and a warm full mark. I always like to have check mine after driving when I know the car is warmed up.


#7

The transmission should be warmed up, so, yes, the car should be driven before checking the fluid. Set the parking brake, then shift the transmission into EACH gear for a few seconds, then finally into PARK. Then, with the engine idling, remove the dipstick, wipe it clean, then reinsert it. Pull it out a second time and check the fluid level.

The pink color is good. That’s the color it should be.


#8

Have a driveability man look at it. It could be something as simple as a TPS (Throttle Position Sensor) The computer uses inputs from different engine and transmission sensors to know when to shift the transmission. Dont condemn the transmission just yet and dont let somebody tell you its the transmission without checking out the engine first.

transman


#9

thanks transman. I dont quite understand though, what’s a “Driveability Man” ?


#10

A driveability man specializes in engine performance/tune-up.

transman


#11

There are a couple more things to check:

  1. Transmission fluid: Pink=good Brown=bad

  2. Check for a dragging brake

  3. Check wheel bearings

  4. Check the differential and half-shafts


#12

If the level is “fine” with the engine off, there usually isn’t enough transmission fluid. Always check it when the engine is running, as the other post said to do.

Overfilling a transmission is just as bad as underfilling.