95 LeSabre Transmission Problem

[MikeS21]

I have 127K+ miles on my LeSabre. I have had the vehicle for about 6 years and have had the regular transmission serviced (filter/fluid changed, etc.) three or four times since I have had the car.

The last couple months, I have had 3-4 occassions when I am stopped at a stop sign, and when I go to pull from the intersection, the transmission gives me a good jolt - and then it takes off. When I say jolt, it almost feels like you're spinning your wheels in gravel before you actually take off. I can't say for sure, but it is as if the engine races to a slightly faster level of RPM (faster than idle - like you would at a stopped position) and then the transmission tries to kick in at the higher RPM.

Now, the last couple weeks, I have noticed that on about four occassions, as I have left the intersection, the car just dies. Out of those four instances, I really only felt one time a good jolt. My mechanic took the car and drove it, and of course, it never acted up on him. However, he told me about the torque converter solenoid problems on this car, and he suggested that I might have a problem with the solenoid because he said he noticed a vibration around the 3-4 shift point, and he said that could be causing problems in the lower shift points as well, and that may be leading to the engine cutting off. He said that he did all the usual transmission tests and felt no signs of slippage or other transmission problems when he drove it.

Here's my questions. Are my two problems related or am I looking at two separate problems? Does the torque converter solenoid sound like the cuplrit?

Wost Case Scenario: How much would a transmission rebuild set me back?