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Avalon Transmission Issues

I was wondering if anyone else has had the problem I am having with my 2005 Avalon XLS (just under 36,000 miles). When I back off the accelerator and the car begins to coast, I feel a drag on the car as if the torque converter is not releasing properly. The problem only occurs after the car is fully warmed up. I have noticed a drop of about 15% in my milage. I have had the transmission fluid checked and taken the car back to the dealer. They responded only that there weren’t any codes and the transmission was working properly. I don’t think they test drove it. Note: This all started after the system was flashed as part of last year’s recall. Before I pursue this further with the dealer, was just wondering if this has happened to anyone else.

 I am not suggesting that it is the cause of your issue, but I have to ask.  When was the last time you had the transmission fluid changed?  That is one maintenance item that seems to have fallen off the standard maintenance list for many people.  I suggest that by 36,000 miles you should have had at least one transmission fluid change (not flush).  

 Note: changing the fluid after damage has been done, will not fix the problem.  Again, I am not suggesting that any fluid change you have or have not done caused a problem. 

A common event is someone will notice a transmission problem and change the fluid only to have the transmission fail shortly after.  Changing fluid will not fix an existing problem and by the time a transmission starts acting up, it is too late for a fluid change to stop it.

I can’t really tell you what is going on - with only “feel a drag” to go on its unlikely that anyone can say much with confidence. (E.g. maybe you have a dragging brake instead of a transmission issue).

But I will say that if there is a transmission issue, a drop in gas mileage would be likely if the torque converter never locked - as opposed to the reverse. Its also the case that if the torque converter was staying locked up you’d find the car stalling out when you stop.

I’ll also say that if the car wasn’t driven when you brought it in then it wasn’t given a full evaluation.

Of course, it is the case what you describe is consistent with something like a dragging brake (drag on the car & drop in mpg).

Dealers service departments possess no special magic. You could take it elsewhere for a second look - reputable, local, independent shop. Some specialize in certain brands like Toyota.

After having gone through some 1,500 threads related to the Toyata Avalon, I have finally figured out that the problem did occur when the ECM was reflashed. Apparently this was Toyota’s fix to numerous problems they have had with the 05 thru 07 transmissions. There have been a number of Tyota Avalon owners who have reported the same problem. It is really anoying and will probably result in a new car purchase. Don’t think it’s going to be Toyota.

What are the RPMs cruising at 40 and 60 MPH?
And did they change after the reflash?

If you noticed a difference in tranny operation right after they reprogrammed or updated your ecu and tranny computer I would say exactly that to the dealer. I am trusting the seat of your pants assesment as you would know best any differences in the way the tranny is behaving better than any of us. I bet the new programming is messing with the torque converters operation…