Plzhelp

Hello, I was hoping if somebody could help me out. About 1 and a half months ago I had the front tires replaced and rotated on my 2001 Grand Am 4 cylinder. I drove it down to California and noticed that it made a kind of low pitched sound that I had not heard before. I thought that maybe just the tires were getting worn in. Anyhow, I replaced the battery two days ago and then yesterday I pulled into work and saw that the TRAC OFF light and SERVICE ENGINE SOON both came on in my dash. I then noticed that whenever I shift the car from park to drive it makes a loud thud and jerks. Also when I'm driving, it's an automatic tranny, when it switches from first to second and second to third, its much rougher than it was before. I've read a bunch of the threads in this forum and from what I can understand it could be a wheel bearing sensor, hub, or transmission. If it is a transmission do these two dashboard lights always come on when the transmission goes bad or is this more related to the hub/sensor? Also am I better off taking this to a dealer or a transmission shop for a diagnosis. I trust the transmission shops before I'll trust the dealers.

Gooman18

Do you have a warranty? If so go to the dealer. Have you checked your transmission fluid at all? Maybe that could cause rough shifting. Start with the small things before taking it in you know?

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They teach you to drive "Defensively". That leads me to one query. Who is playing offense? The answer...Me.

Plzhelp

I plan on taking it to the dealer on Monday to have them simply have it checked out. The car has 61K miles on it and so the warranty has expired. A few other things I have noted: I started it yesterday and both of those lights were off. After driving it around and hence the car had gotten to operating temperature, both of the lights back came on again and the shifting problem returned. Any help would be greatly appreciated.

xeroinfinity

Plzhelp , Sounds like you bearing/hubs are bad. the lights on yuor dash indicate that much. but trans troubles dont throw SES or SVS codes. Either way your going to spend a few dollars to get it fixed, Good Luck.

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1999 Grand Am SS 3.4 OHV

MT-2500

The noise could point to a wheel bearing or bad tire.
The lights on the dash are telling you it has a code set in the computer system.
Depending on the code sometimes a trans will go into fail safe mode and cause hard shifting.
You dealer can get the codes and they should point to the problem.
The noise and code both could be caused by a bad wheel bearing. remember the wheel bearings have VSS sensors built in them.
If the dealer finds a code no post back code no.
MT

grs7

Take in in and have the codes read. I had the same problem with the rough and jerky shifting. It turned out that the TPS (throttle position sensor) and upstream oxygen sensor were bad. Changed them and it solved my problem.

Plzhelp

Funny thing. I remembered I had changed the battery and unplugged the sensor that measures the air temp. in air inlet hose. Once I plugged that in it has worked fine. The other hilarious thing is that I took it to AAMCO and they said I had a bad tranny and it would cost $2300 to replace it. HA HA.

MT-2500

Thanks for posting back and letting us know how it went.
And we are glad you got it figured out and fixed.
Good thing your memory came back to help you out.
It saved you some bucks.
I have done things like that to.
The trans shop with the bad tran crap is the sad part.
I know there is good and honest trans shops but the ones that pull stuff like that need to hung out to dry.
You were wise enought to catch it but a lot of people would have let them replace or rebuild the trans.
MT

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Remember proper testing gives us the answer to many problems.
MT