ok guys, i'm having big problems with my car. i'm going to try my best to describe in detail whats going on so please take the time to read and help me out.

the car is a 2002 cavalier z24 with an auto tranny and 47,500 miles on the car. here's the deal...

about 2 weeks ago i get in the car and start it up. after driving about 45 seconds it starts shaking violently and acting like it wants to die. i stop the car, put it in park and look under the hood. everything looks ok. i rev the engine under the hood and it kind of sputters and then revs a little bit. i shut the car off, start it back up and it runs fine.

i didn't have anymore problems until today...

i'm driving home from work and i'm about 3/4 of the way home. i notice my "trac off" light is on. car is in drive, ebrake is all the way down. i decide to try to get it home. i get off the freeway and hit a stop light and notice the car is shaking bad again. the light turns green before i get a chance to shut it off and restart it. so i leave the light and get ready to go up the hill that leads to my apartments. the car shifts 1st to 2nd, 2nd to 3rd, 3rd to 4th all under 2000rpm's. as i go up the hill the car has a strange "whine". thats the best way i can describe the sound. it wasn't a growl, it was a whine. i end up pulling the hill at about 25mph.

i get the car home, its shaking. the "trac off" light is on but there's no check engine light. i turn the ignition off and back on to see if its throwing a code at me, nothing. i start the car and it seems fine again. i plug it in to an OBD11 reader and it comes up "pass, no codes." wtf? i decide to take the car to the dealership for an opinion (no longer under warranty dammit). the mechanic i talk to says it sounds like the transmission is going bad. they want $2200 plus labor for a new tranny or $750 plus parts to rebuild.

i call my dad and get directions to his tranny guy. i'm on my way to my dad's tranny shop(about a 15 minute drive) and half way there the car starts shaking. i pull over, shut it off, it gets me to the tranny shop. the tranny shop is closed so i take it to my parents house (about 5 mins away). right as i'm pulling into the driveway it starts shaking with the "trac off" light on, but this time the "check engine light" is also on. i turn off the ignition and turn it back on to check for a code. the check engine light isn't flashing to show me a code, its just on.

while i'm driving the car has the weird whine to it. it also shifts EXTREMELY hard. from 1st to 2nd it shifts hard enough to take the whell out of my hand...thats just under normal acceleration. with the exception of when i pulled the hill, the car is shifting really high. the engine revvs up to 3300rpm from first to second and up to 3500 from second to third.

any help is much appreciated, if you have any questions or don't understand parts of that just ask.

please, i'm not in a good mood. i don't want any morons telling me i should have put this in the tranny section. i'm not sure if its a tranny problem or not so i put it in the general maintance. i'm also going to double post and put this in the regional forum to see if any of my local cali guys can give me a hand or maybe help find me a trans for cheap if thats what ends up being the problem.

thanks for taking the time to read and for any suggestions/advice/problem solvers.

brian



GO PATS!!!

sounds to me like you have a torn up scrotum rotator cuff in the gerter belt housing































no but seriously lol...sounds like your tranny..

Well first off when the PCM detecs a problem with the trans, and it sets a code ALL shifts will be hard in ALL types of driving, because line pressure is raised up and the trans enters fail - safe mode.

With it revs up to 3500, sounds like the trans is slipping, and it isnt catching the next gear.

I would say your trans is history.




- 2004 Cavalier - 124k, owned since new

one of my so cali guys said he had the same problem. says the IAT sensor was bad and the car went in to a "limp mode." can anyone else back that up before i take it to a shop?





GO PATS!!!

ok...i figured the IAT sensor is only a 15 dollar part so i went and bought it. i put in the new sensor and took the car for a drive. its not shifting as hard as it was yesterday, when it gets in the higher rpm range where it needs to shift it doesn't have a whine, and the "trac off" light didn't come on. yesterday when i shifted from park to drive the car immediately lunged forward like i wasn't hardly pressing the brake, today it didn't do that...granted, i only drove it for about 5-8 minutes so i'm not completely convinced. can anyone back up that it could possible be THAT easy?? my tranny shop is closed until monday so i have until then to see if its not the tranny. i'm driving the car back from my parents house to my house for about a 20 minute drive to see if it still acts up. let me know guys...thanks

brian




GO PATS!!!

i put the new IAT sensor in and drove the car home. it was shifting as smooth as it normally did. it was shifting where it was supposed to and not drawing it out to make the engine whine. all the sudden the trac off light pops back on. i pull over and its shaking again. i turn the car off, start it back up, light is off. i go from park to drive and the car jolts. after that it made it all the way home with no other problems shifting fine again.

i talked to my wife's uncle who is a transmission specialist and he says that the inconsistancy of the problems makes it sound more like a sensor(or two or three) are going bad, not the transmission. another thing he said might be the problem is the line pressure is too high. according to him, if the line pressure is too high it would be because the sensor thinks the car is up in the higher rpm's which would cause it to shift hard.

i'm out of ideas, i'm tired of screwing with it. i'm still up for any suggestions or comments, but i'm just going to take it to the tranny shop on monday and have him run a complete diagnostic check on it. i'll update once i know whats up for future use for someone else...thanks guy. keep the comments and suggestions coming.

brian



GO PATS!!!

First off it isnt your IAT that can cause that, it is the MAP sensor. If the MAP is saying there is more air going into the engine than there is the trans will shift harder because it will think the RPMs are higher.

I would check for cracks in the MAP vacuum hose, if none are found it may be the MAP sensor.

IAT is the just the sensor telling the computer what the air temp is.






- 2004 Cavalier - 124k, owned since new

In your first post you mention a “check engine light on” did you ever get the code for that light.
The “trac off “ light will come on if the computer detects a problem, that does not mean a light will come on.
I also believe its an engine problem, the transmission operation is dependent on the proper function of the engine.
Just a guess from past posts if it’s the 2.4 its most likely the sparkplug connectors.