Transmission or Electrical???

And the saga continues.....
I have an 02 GT, I bought it used in 02...ever since I've had it the lights (interior and exterior) flash like a damn disco ball...but only occasionaly. Everytime I bring it to the dealer they cant find the problem, looks and acts to me like the alternator, but no diagnosis. Anyway, recently my check engine light came on and my transmission started SLAMMING into gear while I was driving...again only occasionaly, seems more like when the engine is hot. I had the computer read and it came up with an O2 sensor gone and a P1811 code which is a slow, long shift (or something like that). I had the O2 sensor changed and a complete Transmission fluid and filter change. I picked the car up and the Check engine light was off and all seemed well. After about 90 miles the check engine light came back on and instantly my transmission started to slam into gear again. I had it put back on the machine and it said the Mass air flow sensor is bad. I have heard that maybe with the electrical problems that the car seems to have that maybe it is that that is making the tranni act up and not the transmission itself....any thoughts or ideas...cause I'll tell ya, I love my car, but am really getting fed up with it all.
Thanks for any help I can get
:shakehead

I have a GP 2001 3.1 . As far as for your Int/Ext lights, if they are going off in unison, looks like a electrical short somewhere. With your tranny, I had the same problem. Its like driving down the highway at 60mpg and pressing in the clutch in and out. I replace the TCC solenoid and it worked for a short while, but then my speed sensor (P0502) went out so I replace it and so far so good. You might want to talk to a good transmission shop and let them scan it. The only problem with a good tranny shop is you will have to wait to get your car in. They are that busy. If your car jerks alot while driving in the city, I learned something here in the forums that worked. You can unplug the tranny wire harness from the tranny. I'm not sure about the GT, but mine was right below the air intake line from the air filter to the MAF sensor. You just grab by the plastic and give it a good yank. But here's the bad news...your gas mileage will suffer BIG TIME! The reason is that you are essentially driving in 3rd gear so your RPM will always be around 3000 dropping to 2500 on the highway. Also your tranny oil will get dirtier faster and my car ran warmer in the city. It really feels awful at first but I drove my car like this for about 6 months like this. If you are a really good mechanic you can change the solenoid yourself. Parts cost $30 for the solenoid and $70 for the gasket. Labor was $450. The solenoid is on the driver side so you would have to remove all thats in its way. I'm a shade tree mechanic and I would'nt tackle it. Any way I hope this helps. Good Luck
Gil






And the saga continues.....
I have an 02 GT, I bought it used in 02...ever since I've had it the lights (interior and exterior) flash like a damn disco ball...but only occasionaly. Everytime I bring it to the dealer they cant find the problem, looks and acts to me like the alternator, but no diagnosis. Anyway, recently my check engine light came on and my transmission started SLAMMING into gear while I was driving...again only occasionaly, seems more like when the engine is hot. I had the computer read and it came up with an O2 sensor gone and a P1811 code which is a slow, long shift (or something like that). I had the O2 sensor changed and a complete Transmission fluid and filter change. I picked the car up and the Check engine light was off and all seemed well. After about 90 miles the check engine light came back on and instantly my transmission started to slam into gear again. I had it put back on the machine and it said the Mass air flow sensor is bad. I have heard that maybe with the electrical problems that the car seems to have that maybe it is that that is making the tranni act up and not the transmission itself....any thoughts or ideas...cause I'll tell ya, I love my car, but am really getting fed up with it all.
Thanks for any help I can get
:shakehead

And the saga continues.....
I have an 02 GT, I bought it used in 02...ever since I've had it the lights (interior and exterior) flash like a damn disco ball...but only occasionaly. Everytime I bring it to the dealer they cant find the problem, looks and acts to me like the alternator, but no diagnosis. Anyway, recently my check engine light came on and my transmission started SLAMMING into gear while I was driving...again only occasionaly, seems more like when the engine is hot. I had the computer read and it came up with an O2 sensor gone and a P1811 code which is a slow, long shift (or something like that). I had the O2 sensor changed and a complete Transmission fluid and filter change. I picked the car up and the Check engine light was off and all seemed well. After about 90 miles the check engine light came back on and instantly my transmission started to slam into gear again. I had it put back on the machine and it said the Mass air flow sensor is bad. I have heard that maybe with the electrical problems that the car seems to have that maybe it is that that is making the tranni act up and not the transmission itself....any thoughts or ideas...cause I'll tell ya, I love my car, but am really getting fed up with it all.
Thanks for any help I can get
:shakehead

The 4T65-E tranny you have is sensitive to the conditions of your engine. Something as simple as bad spark plugs or wires can make the tranny act up, etc. In your case the MAF problem needs to be corrected before thinking your tranny is bad or has problems.

I know of one situation where a guy went through two trannies and found out later that he had a clogged catalytic convertor. This may not be your situation but it supports my point. He had the P1811 error code too. Dealer changed out the PCS solenoid per a GM TSB and he still had the same problem.

Lastly, are you getting any whining sound from underneath the hood?

Hi Thanks for the replies. No I am not getting any whining. I figured that about the engine problems first, which is why I am trying to get everything fixed first...I'll tell ya though it's one thing after the next. The tranni doesnt slip and it seems to be shifting at the right times, it just shifts very hard.. its at around 2300 rpms at about 70mph, so that seems fine. When they changed the fluid and filter though there was metal chips in the pan. . The MAF is set to be changed next week, so I'll keep ya posted....thanks again