Torque Converter Shudder

The good thing about an automatic transmission like the 4L65E is that many parts of it are modular. That means they can be repaired as units, rather than piecemealing them in a series of repairs. With that said, this is one time you can be happy that this particular tranny is so modular in that the torque converter can be repaired or replaced with minimal disturbance to the rest of the transmission. Yes, it is true that transmission repairs are expensive, especially in what I call hybrid drive vehicles. Not truly hybrid as in electric/gas, the Escalade is essentially a front-drive crossover-style vehicle. It is advertised as an all-wheel-drive vehicle and it really is. It began life as a front-drive vehicle, however, Caddy dropped in a viscous coupling-style differential so that when the wheels sensors and other sensors such as the throttle positioner sensor sense the engine beginning to overrev due to lost traction, the traction is shifted around via the viscous coupling so that the wheels with best traction get the most power.

This is truly intelligent all-wheel-drive. The particular wheels receiving the traction, by the way, are determined by the sensor arrays that are feeding information to the tranmission control unit as well as the car’s electronic control unit.

I think that your Escalade needs a trip to a qualified independent shop, if you want to avoid paying dealer costs to determine the exact problem as you said that you changed the fluid which helped for a bit while the filter only made matters worse. Actually, you should have changed them together. It’s possible that the new fluid’s detergent properties started to eat into various deposits that were inside the transmission, however, because the old filter was still in place, catching things, the deposits never made it through to the other side. However, when you changed the filter, assuming you put in new fluid again, you freed up even more deposits that may have overwhelmed the new filter, causing other issues.

The problem with vibrational problems is that you can really never be sure where they originate. What seems like a torque converter problem may really be a problem with the gearing or a pinion gear could be slipping or there might be a problem with the output shaft on the transmission itself. If there is a problem on the output shaft, it could be that a seal or a bearing or there might be an occasional shaft misalignment. The real issue is that the problem is a vibration; something you feel, rather than a noise or a leak or constant power loss.

Finding the cause to this will likely take some time, however, you could be right in your initial analysis about the torque converter. Converter issues can fit the diagnosis you gave. They might also be something else. The bottom line is that your Escalade needs a visit to the “doctor” to find out what is making it perform poorly at times.