[russlaferrera]

My problem is on a 1996 Buick FWD 4T60E Trans chatters at 40-70 MPH when it is hot. Only on acceleration. Only sometimes. Only after it warms up for an hour or so.
The trans is a GM Re-manufactured unit that has about 40K on it now
The old trans was doing the same exact thing until it died on the road.
I have taken it back to the dealed for warranty. They replaced all the solenoids . Seemed OK for awhile. The fluid has been changed. ScanTool states OK.

Please help!!

[Chazmac]

TCC is the cause of the chatter. There are several reasons the chatter occurs, none of which you can fix in the car.
The TCC circuit and converter needs serious attention, attention it will not get at a GM dealer.

[russlaferrera]

chazmac,

Thanks for the info!!

I am going on a 300 mile trip Will hook up the scan tool to see if I get a DTC code.

The trans and converter were changed about 40K ago, Plus 2 filter/complete fluid changes were done. The old trans did the same exact thing. Just in the warm weather.

Is there anything in the PCM or Temp control that may mimic these conditions?

I find it odd this trans is doing the same as the old one.

[Chazmac]

Changed or rebuilt?
The TCC oil control circuit is the likely culprit, caused by valvebody control problems. Sometimes the bearings that support the pump and input shaft die and cause the same issue. Not very favorable conditions for longevity...

[Ricky Rocket]

Does the chatter only happen when the TCC is engaging and then quit after it applies? Or does it continue to chatter all the time that the TCC is engaged? If it keeps on chattering when the TCC is on then I would first look at an engine miss. When the TCC is on you basically have a mechanical connection between the engine to the trans and any little engine miss will be very noticeable. Usually it is a spark plug, wire, or coil problem that can cause the miss. Watch your misfire count on the scan tool when the problem occurs, this will lead you to the right cylinder.

Let us know what you find,
Rick

[airworld2]

tcc slip or chatter would set code, I also suspect something other than tcc slip. data stream will show history and live data on obd2 system in your car

[russlaferrera]

Trans was swapped out w/GM goodwrench replacement trans. After 2 plus years the replacement trans started to act up with the exact problems.

Took it on a 300 mile trip this weekend 20 min into the trip it started to chatter at 45-70mph under a load (acceleration). The scan tool ( actron) shows everything was OK.

I made the car chatter for about 15 seconds under acceleration, to about 70mph. I thought it would set a DTC code. WRONG. No code

I then shifter the car into 3rd gear and the chatter stops. The chatter only happens when the car is-warn and mostly in hot weather.

The engine runs great

[Ricky Rocket]

Even the slightest engine miss will be magnified when the TCC is engaged and the fact that it is worse under acceleration makes me think of an ignition problem. Have you done a tune-up recently? Have you removed any spark plugs or wires lately? I would take a really close look at the plugs and wires and replace them.

Does your scan tool let you look at missfire data? If it does this would even tell you which cylinder is missing under load.

Let us know what you find,
Rick

[airworld2]

rocket has you headed right, even a slight tcc chatter would show up. data stream shows tcc slip 1- 20 rpm is normal on pwm 4t60e system depending on duty cycle of pwm solenoid more than 120 rpm slip sets 1870 and 1811 codes and will shut of tcc solenoid off until key is turned off and restart engine reset ecm occurs. again you need a good scan tool and software to watch live data as you drive and watch misfire data. could be injector, wire , plug, coil. could also be inside the ecm (computer) this might be a hit and miss problem

[russlaferrera]

The engine was tuned by me 6 mo. ago new wires plugs filters etc. The engine runs great, even under a load. When the trans starts to chatter I let off the gas and it stops chattering. Should I accelerate even a little, it will continue.

After 30 seconds or so the car may run fine. It is up to the car.

There are no codes pending or set.

[Ricky Rocket]

The important thing to realize is that the engine can have such a slight miss that you will never notice it because of the torque converter operation (in unlocked mode) will cover it up because of the hydraulic coupling. As soon as the TCC engages you have a 1:1 mechanical coupling and the engine miss will show up. You may NEVER notice it until the TCC is engaged!

Did the same thing happen before you tuned the engine up? Or has it started acting up after.

Sure, there may be other causes but I would put pretty good money on the engine miss area. This could be tough to find!

Good Luck,
Rick

[russlaferrera]

I don"t agree with an engine miss. My rational is the old trans did the exact same thing until it blew up. The replacement trans lasted 2 years until it started doing the same thing.

Since the car has been tuned up twice in the 4 years. If there is a miss the replacement trans should have acted up when it was installed.

My guess is the TTC is not locking up properly. But I can not figure out why. The car has a mind of it's own.

The service manual does not address the problem if there is no DTC set.

PS: Do Not get me wrong I am not saying you do not know what you are talking about. I am saying I have tried to eliminate as much of the possible causes everyone has given me so I can isolate the cause. The car looks and runs grate ....all except the trans chatter .

[Ricky Rocket]

Hey, no offense at all! You are the one that can drive and listen and feel what the car is doing. It is odd for this type of chatter to be inside the trans but not impossible. Have you had an experienced technician drive the car when it is acting up? Also, does it act up in 3rd gear (manual 3rd) with the TCC engaged, or only in 4th? You could have a 4th clutch slipping and causing the chatter.

Good luck,
Rick

[airworld2]

after re reading your post 96 will set code for tcc slip no if and or butts, and will shut off tcc solenoid. you can do a tune up but if your fuel injectors or something random occurs it can seem as you tcc shutters.If you step off the gas then back on do you feel the shutter on tcc apply?or does this only happen with your foot on the gas.shutter can best be described it feels like your running over a cobblestone road or ruff road, jerking or stumble is sometime mis- diagnosed as tcc shutter when in fact is engine performance trouble. if you had a stand alone trans controller that would let you apply tcc on demand.

[russlaferrera]

Fuel injectors were serviced and a new flex plate was installed about 6 mo. ago They inspected the converter at that the also. (Note: I was in the hospital at that time and was unable to perform the repairs.I don't want to sound like a wuss....LOL)

The dealer ran the scope on the engine and took an 1:30 min road test. The car ran great...and it did... the car ran for 3 mo. then it started doing it again. It seems that this is some how temp related?

Now the frequency has increased and I have tried most of everyone's suggestions (With my limited tools and Well lets face it I am 60 and my brain shrunk)