I've spent the last couple of days looking through forums and asking Google in many different phrasings but cannot find the exact issue I'm experiencing with my 2005 LeSabre with almost 130,000 miles.
Recently, if I decelerate/brake fast then immediately press the accelerator, the transmission seems like it hangs then slams into gear with a clunk. This will also happen if I am going through town leisurely, then accelerate abruptly, however this is more of a stumble than a clunk.
If it drive normally with light acceleration, like normal trips around town, stopping at stop signs for a few seconds or more, I don't experience any of the above and the trans shifts like butter in all gears.
The trans fluid has a few thousand miles on it. I suspect it may be a little overfilled from recent checks. I also am certain the front left trans/motor mount is smoked. The motor moves back a decent amount when revving in park and the mount looks bouncy. I plan to replace this in April when the weather is more favorable.
Thank you!