ok this is my 99 Park Ave again. It had a hard shift thru the gears and if you shut it off and restarted it was fine. Took it to my tranny guy and replaced the pressure solenoid, problem gone except it still had a fairly hard 3/4 and 4/3 shift.


Now.. after tc lock up it is shuddering if you lightly touch the brake it clears right up. Called my tranny guy said it is probably the tc. I tried the Lucas no difference. At highway speeds with cruise on it seems like about every 5 seconds you are hitting a rough patch in the road.

It is not throwing a check engine light and seems to run and start fine.The car has 98k on it and was serviced up until 70k by a GM dealer where I bought it . I have all the records.

Sound like the TC ? I wondered about plgs and wires but they appear new and in good condition. Wires are covered in looms. Also it doesn't seem like if this was the problem it would come and go every 5 seconds.

Thanks guys

I called another tranny shop today and explained my symptoms, he said " well it sounds like you nedd a tc and a complete rebuild, valve body etc etc" 2000.00 !!!


Now I had a similar problem on my 99 bonnie a few years back and the dealer replaced the tc and I ran it about another 160k miles with NO problems. Why is this shop telling me I probably need a complete overhaul ?

The vibration is not real noticable in fact other people in the car have a hard time feeling/hearing it but it is there and does seem to go away or is much much better after taking out of OD.

Whacha think ?

Thank you

Are you sure its the trans sounds like what mine did when it had bad wires it only did it when in od and going up an incline

Not ruling out a TCC issue, but 95% of all problems with symptoms like yours are ignition related.

If you don't know how old the plugs and wires are, replace them. Check your coils per the Techinfo article.

I'd like to see your plugs. All 6, laid out in order (remember which came from which, it can aid in troubleshooting).

well... he was going to have me bring it in and drive it with a scanner on it and said he could tell me weather it was the tc or not. Its doing the same thing my Bonnie did at 68k and when they chgd the tc it was fine and still is at 247k.

Should I let him do the scan tool ? Will it show for sure if its tranny or not ??
The wires on this were replaced about 20k miles ago with AC Delco wires, plugs at the same time. None are touching each other or touching anything else.

The shudder happens just before the tc loks up and then every 5 seconds after its locked even on flat roads. Feather the brake pedl and its fine. Just seems funny that I just had the pressure solenoid done a few weeks back and it shifts great now ??


If it is the tc would it be ok just replacing the tc NOT doing a total overhaul ? That is what they did on my Bonnie.

ok i tested the secondairies per instructions all check ok. Do you really think i should chg plugs and wires before having him do the drive/scan off the tranny ? This thing starts and runs great. Never stumbles gong up hills or otherwise just the slight vibration feel/noise when in lock up ?

Thank you again

any other ideas or should I let the tranny shop run the test ?

Let 'em run the test, but keep in mind they WANT your car in the shop.

But I don't think you should go back to them until you rule out ignition issues completely.




In the future, please have more patience before bumping a topic.

When you lightly touch the brake (not enough to slow the car) AND keep your foot on the gas to maintain your speed, the tach should jump about 300 rpm. If that also makes the shudder go away, then the vibration is probably in the TCC. The switch that controls it is pressed up against the brake pedal lever, probably the second one as you look up the lever. One of them is the brake light switch--it was the first one in my Buick. Easy enough to check --just have someone watch your brake lights, push the pedal down, then activate and deactivate the switch. If it affects the brake lights, it'* the brake light switch. Both switches are usually adjustable by turning them in or out--at least that used to be true--I haven't looked at them on my Pontiac. If you adjust the TCC switch so it'* no long pressed up against the brake pedal (or remove it from it'* holder), that essentially turns off your TCC and it will never engage. If you do that then test drive the car and the vibration is gone... well, you have your answer.
While TCC problems are pretty unusual, mine did the same thing and it was the TCC. It'* pretty easy to check if you can get on your back and poke around. It could even be a bad switch, although probably not. The cheap, easy fix is seldom the right one, in my experience. ;-(

took it in to the one shop near me and they drove it with the scan tool and me in the car. It is slipping and it is the TC shuddering.

they will not just do the TC they want a full rebuild to warranty it 2k !

He did say they would do a flush and re-fill with a friction modified fluid for 150.00


Now again my Bonnie did the same thing and I just did the TC and this was at 60k and its still going fine with 247k on it now !

I am tempted to try the same thing again. My buddy will do it for 500.00 TC and TCC solenoid and fluid and filter. I am sure he will check the valve body ETC while he is in there but the guy is super honest .

Ideas ???