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Torque Converter Clutch shudder?

Our '95 Park Ave Ultra has been exhibiting symptoms that I've been told here could be due to the torque converter clutch. When driving at steady speed, e.g., 60 to 70 on the freeway, there is a short hesitation, sort of like something is slipping in the drive train. This has been happening over the last couple months, with increasing frequency. I've had it to a transmission shop and my normal service shop, but it would not do it for them when they test drove the car. Not too surprising since it tends to happen only after driving for 20-30 minutes.

Then today I noticed another similar smyptom, but while at a stop light, in drive with foot on the brake. Sort of like something slipped that caused the engine to loose speed. I watched it on the tach. It would be idling at about 1000 RPM (AC was on), then it would drop down to perhaps 850 for a moment and then return to 1000. I suppose this could be attributed to the AC clutch kicking the compressor in and out, but I've driven this car nearly 10 years and never noticed it before. And it had an erie similarity that reminded me of the shuddering at road speeds, perhaps in the timing of the event.

So one question is are these two symptoms related? Someone here suggested the shudder might not be the TCC at all, but rather the engine having an intermittant missing problem.

The other question is how to narrow down the diagnosis. I'd sure hate to pay for a transmission/TCC overhaul or what ever (which sounds expensive) only to have the problem still with me.

TIA

Ed

Reply to
Ed
Loading thread data ...

Bad plug wires.

Reply to
=?x-user-defined?Q?=AB?= Paul

Reply to
Shep

Thanks, Paul. Sure is an easy and cheap thing to try, and given their age it should be done anyway.

Ed

Reply to
Ed

Thanks, Shep. Guess I'll have to ask the guy at the tranny shop to drive the car for a few days.

Ed

Reply to
Ed

When you get new wires, be sure & get a good quality. We've seen many lesser brands perform as poorly as the old ones. s

Reply to
sdlomi2

Thanks. Any particular brands I should ask for, or just the highest priced ones?

Ed

Reply to
Ed

I was wondering if the scanner for this year of car would store transmission codes, i.e. gear ratio error, meaning the output speed doesn't correspond correctly with the input (engine) speed for example, or perhaps some more specific code which would point to TC malfunction. If that's the case, the car wouldn't have to exhibit the condition at the time the scanner is connected to it; they could just hook it up initially and look at any hard or soft codes, then clear them and check it in a couple days and see which one re-appears. My Chrysler 604 was diagnosed that way, and it was an '89. Surely you can do the same thing with this '95. As for which plugwires to get (since you say it's due for them anyway) I'd just get the factory original Delcos. At our shop we'd always replace Delco stuff with Delco, since we didn't want the vehicle coming back because the part failed, in which case we'd have to eat the labor.

Reply to
James Goforth

James,

Just to bring everyone up to date, I did replace the plugs with AC Delcos and the wires with the best brand product avaliable at my trusted Parts Plus store... a Federal Mogul brand which I don't remember, for about $40. It ran OK for a while, then after a week or so the engine started missing really bad, and the herky-jerky thing was happening nearly all the time. Before that happened I had made an appointment with the tranny shop, thinking the TCC was at fault because the "brake tap" test stops it. But when it started missing I figured I'd best take it back to my normal garage since maybe they had put a bad air mass sensor on it. Guess what? They tracked the missing down to a failed spark plug... one of theose brand new AC Delcos had apparently failed. I could hardly believe it, but they said they did a compression check and checked all the plugs and #1 was not firing all the time. Now, the engine runs smoothly and, get this, no more herky-jerky!

So, the question now is what cause that plug to fail, and will it fail again and the herky-jerky come back too? I'm betting it will....

Ed

Reply to
Ed

Was the plug fouled? If you have heavy fouling, it may well happen again. If the plug was just internally bad, it may not happen again. I dont believe I have ever seen a plug bad out of the box, but Im sure it happens.

Reply to
<HLS

Yes, it was fouled. However, I can't tell if it is fouled because it had not been firing, or if stopped firing due to becoming fouled... chicken and egg thing I guess.

I picture spark plugs an just a center conductor, i.e., an extension of the electrode. If so, it's had to see how it could abruptly stop conducting. OTOH, if it is more complex, e.g., a resistor or something in there, perhaps it could fail.

BTW, the car did run fine right after installing the new plugs and wires. It was after a week or so of driving that it began to miss.

thanks.

Ed

Reply to
Ed

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