tranny problem 4R70W

when i am driving my 96 mustang 3.8 with automatic[ 4r70w ] every once in a while it feels like a vibration coming from the tranny i think. it lasts a couple seconds,but it may do it once or more, it varys. the tranny isnt slipping that i can tell.would it be a sensor on the tranny or the torque converter. please help me out . thanks larry

Sounds like it may be the Torque Converter Clutch (TCC) slipping. A way to test goes as follows:
When occurring, keep your right foot on the accelerator and with your left foot slightly press the brake pedal. This will cause the TCC to disengage. The RPMs should raise slightly, and if it is a TCC related issue, it should go away at this time. It will come back when you take your foot off the brake and the TCC once again engages. The TCC engages only in 3rd and 4th gears when the ATF is up to a certain temperature (above 80F, IIRC, which should take about 10-15 minutes of drive time in freezing temps).

Additionally, did you check the dipstick? Is the fluid bright red? Or is it discolored, possibly brown? Does it smell burnt? Is it filled to the proper level? Remember to check the level on a level surface with the ATF up to temperature (atleast 30 minutes of driving), and after you cycled through all gears (R,N,D,2, and back to Park).

Sounds like it may be the Torque Converter Clutch (TCC) slipping. A way to test goes as follows:
When occurring, keep your right foot on the accelerator and with your left foot slightly press the brake pedal. This will cause the TCC to disengage. The RPMs should raise slightly, and if it is a TCC related issue, it should go away at this time. It will come back when you take your foot off the brake and the TCC once again engages. The TCC engages only in 3rd and 4th gears when the ATF is up to a certain temperature (above 80F, IIRC, which should take about 10-15 minutes of drive time in freezing temps).

Additionally, did you check the dipstick? Is the fluid bright red? Or is it discolored, possibly brown? Does it smell burnt? Is it filled to the proper level? Remember to check the level on a level surface with the ATF up to temperature (atleast 30 minutes of driving), and after you cycled through all gears (R,N,D,2, and back to Park).
thanks for the information.i took it to the tranny shop and they flushed the tranny and put new filter and fluid in it,they also added a tube of stuff to stop the shudder.it worked.no more vibration.