1998 GT Trans Problem

[Danno94Cobra]

I need some serious help. It's a long story, but I will make it as short as I can.
I have a 98 GT, automatic, minor mods, nothing serious, and I do not have torque converter lockup after overdrive. I took it to the local Ford dealer, and they told me to replace the whole transmission ??? ($2500 bucks) . Anyway I did not like their answer (they charged me 100 bucks to look at it) Then I took it to a well known transmission repair shop. The owner of the shop hooked a computer to the connection under the dash and drove away. The car goes through all 4 forward gears no problem, has reverse and park as well. Shifts smoothly, but won't kick down after I reach cruising speed.

Transmission guy tells me there is nothing wrong with transmission???? His laptop computer shows that the PCM is not asking for lock up to the torque converter. All the sensors are working withing normal parameters. He showed me on the laptop that there was 0% asking for lockup to the torque converter. Man - O - Live batman.... He tells me to start checking the PCM by disconnecting low voltage sensor wires.

I take the car home, run it, and start disconnecting electrical sensors, hoping for a check engine light to appear. Nothing, no light. (it comes on when you put the key in and turn it to start the engine). I disconnect the coolant sensor figuring this will definitly work, but the electric fan comes on, and the check engine light stays off. I then figure that I will disconnect the Idle Bypass wire and this will definitly throw a light. Nothing, except the car almost dies so I recconect the wire before it does.

It is my understanding that the PCM does not tell on itself when it takes a crap. It will tell on everything else, but it will plead the 5th when it comes to itself. I don't want to buy a new PCM and have it not be the problem, and I am afraid to take it back to the dealer who will rip me off for another 100 bucks. notnice:

Any suggestions?? Anyone have this problem before?? Your help is greatly appreciated. Thanks in advance.

 

[blkhorse]

check your brake pedal switch,that kicks the torq. conv out if you touch your brakes. if it's bad it will prevent lock up


And welcome to Stangnet

 

[bhuff30]

Don't worry about not being able to turn on the check engine light imidiately. It will usually require a full driving cycle before the check engine light turns on.

The brake pedal switch seems a likely cause, but there are a few other sensors used too, such as the vehicle speed sensor.

 

[281CI96Coupe]

+2 on brake pedal switch!

 

[Danno94Cobra]

Thanks for the quick responses

I want to thank everyone for the quick replies. I will be checking the sensors mentioned and especially the brake pedal switch. Who would of thunk such a thing??

Thanks again, and I will report my findings after the weekend is over.

 

[Danno94Cobra]

I want to thank everyone for the quick replies. I will be checking the sensors mentioned and especially the brake pedal switch. Who would of thunk such a thing??

Thanks again, and I will report my findings after the weekend is over.

Another thing comes to mind as you all have mentioned brake switch. I have noticed that the brake booster has some fluid (bit more than trace amounts) collecting dust around my brake booster. I have also noticed that the driver side from wheel collects more brake dust than the rest of the wheels after being washed, and used for a few days. I am wondering if the brake booster is part of this problem. This is something I am going to look at as well. I had no idea how much the role of the brakes play in the automatic transmission function. I just hope this is not a killer job. I do not see the large vacuum booster on my GT like the one on my 94 Cobra. It almost looks like it does NOT have power brakes. Is the booster under the dash? (NIGHTMARE) if it is....

I will keep you posted.

 

[Danno94Cobra]

Torque Converter Problems

This weekend was a bit hectic for me, so I didn't have a chance to dig into the electronics and try to diagnose a bad component. I think the brake switch is just fine. I do not seem to have any issues with the lights or anything, and the pedal is not lazy either, no sag. I did however manage to take the car out for a ride saturday afternoon, (by myself) and I really beat the crap out of it. For no other reason than it was just a lot of fun, and I have not done it in a while. Something interesting, I want to share, came as a result of this beating i put it through.

I made a total of three (3) WOT passes out on the rual roads of my community saturday afternoon when all was fairly quiet. I am not going to divulge the actual speeds I reached, I will leave that to your imagination. What I was trying to achieve was to put the transmission into a severe high pressure situation, which I believe I accomplished in the 20 minutes I was out driving around.

The results are:
I now have torque converter lockup and the RPM's at 55 MPH are right in the zone of about 1750 RPM. The torque converter locks up right at 50 MPH or 2000 RPM. I feel this is a little high for a stock transmission I would think that it would lock at about 1700-1800 RPM or about 40- 45 MPH.

My question is: WHY !!!!! This is driving me nuts now. I am wondering if the filter is clogged a bit and slowing the flow of fluid down...maybe??? I have about 110,000 miles on the car and never changed the filter or fluid. Now I do check it on a regular basis, and the fluid is as red as can be, (still looks new) and does not have any hint of being burned at all. Never overheated, no browning, and no burnt smell at all.

Ghost's, who knows. I drove the thing to work this morning and it drove just fine. Shifting was normal 4th gear was acheived at about 37-40 MPH and the torque converter locks at 50 MPH (2000 rpm).

I did swap battery in the car over the weekend with my other car that sits ion the garage. I like to keep it fresh, so I swap it with my truck normally, but I put it in the stang this time. I did not have a check engine light, but I know it reset the computer parameters when I disconected the battery. Could this have had a play in the now normal operation, I wonder how long it will last before it starts messing up again.

I'll kep you posted on my findings as they occur.

Thanks

Danno

 

[Danno94Cobra]

Torque Converter PROBLEM SOLVED

I finally have the problem solved. My torque converter was not locking up for a real good reason. Let me start out saying that I replaced the Instrument Cluster a long while back because the odometer broke, and I need the mileage counter for reimbursment at work. I bought a used one on e-bay and it worked fine, so I thought. It seemed to work fine anyway. I began having problems with the Transmission about 4 months after I installed the instrument cluster. I did not associate a trans problem with the installation of the cluster.

After checking and re-checking electronic sensors, I decided to swap the instrument cluster with the one that was originally installed in the car. I wanted to see if it would make a difference. Now I ran the car for 3 days and I thought everything was great. Shift points were fine, everything seemed normal and WHAM!!!! There goes the torque converter again. Would not lock up, however, because I now had the original instrument cluster back in place, I GOT a check engine light to come on when the torque converter malfunctioned.

I whipped out the trusty code reader I bought at the local auto parts house and had two error codes. Both banks were running lean, which caused the PCM to unlock the converter to prevent overheating of the engine. (Nice failsafe by the way) and I immediatly went and checked my cotton oiled Air filter. I put a cold air induction kit on the car some years ago. The filter goes through the fender wall to grab cold air from outside the engine compartment.

Well, I had to remove the whole assembley to get to the air filter. It is just the way it is designed. When I get the assembly out of the car I inspected the air duct while I was waiting for the filter to dry off. I found 3 decent size holes worn through the aluminum air duct after the filter, (Downstream) and guess what I found. Yup, I found dirt and dust all over the MAF sensors. Holy crap Batman, $6.00 and 10 minutes later the MAF was clean and shiny again, I cut the aluminum Air duct to get rid of the holes, (now the filter sits in the engine compartment) and I proceed to firing up the motor.

All I can say is this: It is amazing that Ford told me the transmission needed to be replaced for $2400.00 and charged me $100.00 to tell me that. It was also amazing that my transmission guru told me the Trans was fine. $6.00 and 3 weeks later the car runs like new. It has so much power, (which was lost because of the dirt slowly accumulating on the MAF sensor) I am totally happy again, and the car runs like a top. I went to Ford and talked with the Service Dept Director and asked him for my money back for a faulty diagnostic on my car. He did not want to give me my money back at first, but I told him that I repaired the car and it only cost me $6.00. I told him this in front of about 5 customers and began making a scene out of it.

I did not want to tell him what I found, and I asked him to pay me for my time before I let him know what the problem was, yes I did this in front of the customers as well. Of course he just laughed, and I expected about as much, but I made him promise to refund my diagnostic fee if what I did to the car would have fixed it. He told me fine in front of many witnesses and I explained what I did. You should have seen the look on his face.

He told me that what I had done would have cleared the problem I had, and I asked him if he wanted to go for a ride that I had the car right out side. He said he trusted me and told the clerk behind the counter to refund my money.

So there it is....Problem solved with a $6.00 can of MAF cleaner, a hack saw and about 10 minutes of time. (not to mention all the hours I spent checking out the electronics)

I hope this helps people down the road if they run into a similair situation. If your torque converter fails to lock there are about 15 different sensors that control it. You have to check them all just to be sure. Check the easy stuff first and if you do not get a check engine light popping up, check for codes anyway just in case.

Codes for lean condition bank 1 is P0172 and bank 2 is P0174 in and OBD-II PCM. If you get both banks lean at the same time, chances are an Air flow problem.

 

[rabidscoobie]

Glad you got that fixed,I would have never thought of that causing probs with the tranny/tq verter.

 

[96GT281]

I do not see the large vacuum booster on my GT like the one on my 94 Cobra.

our cars dont have vacuum boosters they have hydroboost that run of the power steering