The transmission on my Sienna is starting to act up. It has been doing weird things for the past 25,000 miles or so, but lately it is getting worse. It still shifts OK and there is no flare between shifts, but it is acting "harsh" or shudering, especially on a downshift. I don't know how else to describe it, at first I thought there was a broken engine or transmission mount but I replaced them and that didn't cure the issue. I'm pretty convinced now that it is the transmission itself. Another description is that the harshness is kind of "bouncy", just like if one of the mounts was broken. When you are driving along at a steady speed everything is fine, you really notice it only when accelerating or kicking down to pass someone at a relatively slow speed.
Obviously with over 320,000 miles it has seen its tour of duty, but any suggestions as to what might be wrong? I have kept up with regular fluid changes (M1 ATF) and this last time I added Lubegard which had no affect. When clutches in an A/T wear out what are the symptoms?
We still use the van for daily driving, and the engine is good so I am entertaining the idea of a repair or replacement. Suggestions on that are welcome too. A Toyota "OEM" rebuild is about $2000. I've rebuilt everything on a car except an A/T, parts are readily available but I really don't want to go through all the work just to find out it doesn't operate properly, besides the fact that I don't have the 1,00,000 special tools the manual seems to indicate I would need.
Obviously with over 320,000 miles it has seen its tour of duty, but any suggestions as to what might be wrong? I have kept up with regular fluid changes (M1 ATF) and this last time I added Lubegard which had no affect. When clutches in an A/T wear out what are the symptoms?
We still use the van for daily driving, and the engine is good so I am entertaining the idea of a repair or replacement. Suggestions on that are welcome too. A Toyota "OEM" rebuild is about $2000. I've rebuilt everything on a car except an A/T, parts are readily available but I really don't want to go through all the work just to find out it doesn't operate properly, besides the fact that I don't have the 1,00,000 special tools the manual seems to indicate I would need.