I'm having a problem with my '89 that no one can seem to solve. It's a 5.7 auto. Here it goes. Last week while sitting idle, I notice the RPMs' higher than normal, especially since it was fully warmed up. When I'd slow down, and the car would down-shift, it was down-shifting harder than normal. The worst part is the transmission would not shift into 4th gear. I went home and hooked up my Auto-Xray and put it in 'real-time' scan mode, then started driving the car. Everything went back to normal and I got no feedback from the 'X-ray (???). She ran perfect until today, the same problems started happening again. She shifted into 4th once. I'm torn here. I'm not sure if it's an electrical problem or the torque convertor or what. I'm not getting any codes. All fluids have always been topped off. Anyone have a clue on what this could be??

Thank you.

 

If you can't connect to the computer to read anything, you may have a short somewhere or just a bad computer. One thing you might want to check is any wiring you've touched lately, spark plug wires on the header, etc.

 

I haven't touched anything, and she ran fine when I brought it out of storage. After about the 3rd or 4th time I drove it I noticed it started doing this. The Auto-Xray I used just reflected that there were no ploblems detected. I thought the problem might be with the torque convertor (no lock-up), but I wouldn't think that would have anything to do with the higher RPMs' while the car is at idle. It just doesn't make sense.

 

Next time you put the auto x-ray on it, shift into OD and check to see what the scanner has to say about 4th gear. Also, check the TCC connector on the drivers side of the tranny case. Also, when was the last time you changed your transmission fluid and filter.

P.S. The switch for the 4th gear is located in the tranny case in the body under the filter.

 

I took the car out again today, with the Auto-Xray monitoring in real time. It was indicating '4th gear engaged' when I was up to speed but the torque convertor still wouldn't lock up, and the RPMs' just kept climbing. It is still downshifting harder when coming to a stop, and still idling higher than normal. I added Sea Foam trans tune, drove it around, but it did no good, nothing changed.

 

One thing I wanted to add that might help figure this out is with the RPMs'. Like I said, when I put it in park or neutral, it revs higher than it should, and the RPMs' don't go down (fully warmed up). Also, when I'm just cruising along at like 30 mph, and let off the gas the car won't gradually slow down like it should, it just cruises along until I start braking. And from what I see this high RPM problem is what causes the harder downshifts when I come to a stop. So from these problems and the car not shifting into 4th, can anyone think of any other possibility??? I feel like this is something so simple but I can't figure it out, and it's frustrating.

 

Have you by any chance disconnected the Throttle Valve Cable at the throttle body recently?

 

Check the converter lockup connector on the side of the trans. If it's connected like it should be, unplug it and take the car for a test drive and see if your high idell and hard downshift go away.
If so you've found your problem.I've had this same problem before.

 

Trickster, I haven't messed with the t v cable at all. Could that be out of whack?

transambill, where exactly is the convertor lockup connector located? And if this turns out to be the problem, what do I have to replace?

Thanks a lot for your input guys.

 

The convertor lockup connecter is on the drivers side and will be the only one there unless you have a electronic speedo and if you do it's the one closes to the front of the car. I'm not sure what you'll have to replace,hopefully someone else will chime in. I had another trans that I had installed a shift kit into and just swapped mine out.

 

Hello 1BadGTA,

The connector that transambill is talking about is a 4 prong connector with 3 wires that connects to a plug in the tranny case. Inside the tranny case, the Torque Converter Clutch solenoid connects to the other side of this plug. BTW, this plug is a double sided connector that sort of acts as an adapter and just pushs down into the tranny case. Here is a picture of the plug in the case and the solenoid. The plug is #33 and #34 is the o-ring for it.

 

Thanks Trickster. So if I disconnect that switch, and the car doesn't idle high and downshift hard, does that mean the torque convertor needs replacing??

 

No, it doesn't mean that you have to replace the torque converter. Just that there might be a problem with the wiring, the TCC solenoid, or possibly something in the ECM. You might even want to adjust the TV cable and try that as a trouble shooting procedure. I will send some more info the Torque Converter Clutch shortly.

 

Thanks a lot for the man, this has been frustrating. As far as checking some of these problems, how will I know what's bad? One other thing, how do you adjust the TV cable?

Thanks again.

 

Start with this and try them, when you notice a difference in your problem. It will give you and idea of where the problem is and you can correct it.

 

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OK, I re-adjusted the TV cable and nothing improved. Still the same symptoms. Regardless, thanks for the help Trickster. If I do disconnect the convertor lock-up connector on the tranny, and the high idle, and hard down-shift goes away, what would I need to replace/repair?

 

If the wiring and connector on it check good, it would be the torque convertor solenoid inside the tranny oil pan.

 

Trickster, When I get under the car to check the connector, am i just checking to make sure it's hooked up? If it is the torque convertor solenoid, what is the level of difficulty in replacing it? Isn't it fairly rare for something like that to go bad? Sorry about all the questions man, I've just never messed around with these components before.

 

Hello 1BadGTA,

There is a couple of check that you can do with that connector to verify that the wiring is good. Another board member was having problems with his and found that he had accidently painted the connection when he had the transmission down for repair. To replace the TCC solenoid is not a really difficult affair, just rather messy. It involves removing the tranny oil pan and filter, which if you haven't changed the tranny oil and filter is a good idea. This stuff doesn't last forever. No, it isn't rare for the solenoid or associated equipment to go bad especially if the fluid and filter haven't been changed on a regular basis. I will e-mail you some information on this later today. BTW, you don't happen to be at "WHY NOT, MINOT AFB" do you?

 

Could you e-mail me the info as well. If I can just swap out the TCC solenoid in my old trans and fix's the trans. I'll have a extra incase the one I'm currently useing takes a crap on me.
Thanks Trickster:hail:

 

Another quick question. Would the solenoid being bad also cause the trans not to shift from 1st. to 2nd. in WOT. Meaning when I've got 1st. wound out and I manually shift ,the trans stays in 1st. unless I let off the gas a little then it will go ahead and shift to 2nd. or does this sound like a govorner problem? Thanks for any help.

 

Trickster, yeah I'm hoping the connector became disconnected or something simple, along those lines. I won't have a chance to get under the car until tomorrow. I just never had to mess with a transmission before, never had problems with one. As for the fliud, I was hoping I wouldn't have to drop the pan, because the fluid and filter were changed about 10k miles ago, and I put Amsoil in it, expensive stuff ($8 a quart). If need be, I'll do it.
As for "why not Minot"? Yes this is that place. I was in the Military, but got out as couple years ago. Since then, just struggling with jobs (there are none) in this town.

Thanks again man

 

Bad,

What is the TPS voltage at idle? (NOT according to the AutoXray, but a voltmeter.)

What is the idle RPM in DRIVE? (NOT according to the AutoXray nor the dash tach, but a tachometer connected to the coil.)

What are the IAC counts at idle RPM?