4L60E Issue

[Liam Oswald]

I have been having issues with my 4L60e in my 97 Tahoe, in over drive on the highway at a lower rpm approximately 1200rpm i get a strange shudder or almost a clunk as the transmission shifts from overdrive to third gear, If I snap the pedal quickly and give it more throttle than usual it seems to shift down to third smoothly. Only vehicle I have to commute right now so would love to figure out what it is and was wondering if any one else has experienced this. Transmission fluid and filter has always been maintained

I do have a video of the noise just can’t seem to figure out how to upload it on here

 

[studigggs]

Under mild accel in OD, what you are probably experiencing is the torque converter unlocking rather than a downshift to 3rd. When you step on it harder, then you are most likely getting the smooth shift from 4th -> 3rd. Look up "TCC Shudder", there seems to be quite a few causes. Also make sure the "shudder" isnt just a misfire under load which would be more an ignition issue. A data reader should let you know if the shudder syncs up with the torque converter unlocking. It should also log misfires for you.

 

[Jason_Staggs]

Take what I say with a grain of salt, I'm no expert, but I believe that would be your TCC (Torque Converter Clutch) Solenoid if you're only experiencing it during lock up

 

[texas tough]

sometimes the TCC piston in the valve body will wear, and leak fluid past, not maintaining hydraulic pressure integrity,, the solenoid can work, but the valve body isnt working right. as said, a scanner can show u the precise moment the tcc engages, or doesnt. I bought a autel CP9690 and it works great on these trucks.

 

[Liam Oswald]

Under mild accel in OD, what you are probably experiencing is the torque converter unlocking rather than a downshift to 3rd. When you step on it harder, then you are most likely getting the smooth shift from 4th -> 3rd. Look up "TCC Shudder", there seems to be quite a few causes. Also make sure the "shudder" isnt just a misfire under load which would be more an ignition issue. A data reader should let you know if the shudder syncs up with the torque converter unlocking. It should also log misfires for you.

I believe that this is exactly what is going on.
Would like to do a road test but going to have to have somebody ride along to watch scanner since the roads are very icy/snow covered and I’ll have to do it on the highway to get up to lockup.Connected the scanner today at lunch in the parking lot drove around a little and discovered that i don’t have any codes present,also do not appear to have any misfiring and then also checked the cam retard degree which is in spec too. I’m thinking that the next step I’ll take here will be to check the resistance of the PWM solenoid and have one on hand for replacement in case it is faulty..

 

[semperfi]

Interesting, I have the same issue with my '96 Z71 with 5.7 l V8 & 4L60e. No codes that I can read with my simple android reader but I 1st thought it was a miss but now sounds like the TCC. I'll follow this thread & see what's suggested for a fix.

 

[semperfi]

Any updates on this thread?

 

[Liam Oswald]

Any updates on this thread?

Just waiting for the hoist to be available to drop the pan much nicer than laying in the dirt.. did discover that when at lock up if I tap the brake pedal to unlock the converter it unlocks smoothly so my guess that it could be something else