2000 Avalon transmission question for you techs out there

[hrsepwr2]

I have a 2000 Avalon. Recently, it has changed how it shifts into second gear. I will try to explain the best I can.

-When I accelerate aggressively, the car seems to shift from 1st to 2nd gear with no issue.

-When I accelerate moderately aggressive, the car seems to shift from 1st to 2nd gear with a pretty firm shift.

-When I accelerate light to moderate, the car shifts really hard, almost like it doesn't know to shift, then figures out it's time to shift and bangs second gear hard.

-When I accelerate like most people's grandpa, nice and slow/easy, the car shifts from 1st to 2nd gear just fine.

Is there some type of pressure switch/sensor that controls only this shift from 1st to 2nd gear? Every other shift seems to be fine and there doesn't seem to be any slipping of gears anywhere. Other things you should know:

-this symptom has been going on for about 1000 miles now with no change
-the car has 185000 miles
-the trans fluid was last changed at 168000 miles at the dealership
-the trans fluid level is fine
-the trans fluid does not have an odor as if something is burning internally

Please let me know your thoughts. I am mechanically inclined, but these cars really get me down with today's electronics, etc. It took me awhile just to come here to ask the question!

Thanks in advance!

[aigochamaloh]

My 95 does that, except when shifting from 2nd to 3rd. It's been like that ever since I got the car at 95k miles. I now have 150k and it hasn't changed or gotten worse. It kind of bothered me, but I got used to it. My supercharger also stressed the transmission a bit, and the fact that it hasn't gotten any worse is good.

[rkanchana]

I think my problem is something similar. I have a 2000 Avalon with 96K miles. Recently, it has changed how it shifts into second gear. Shifting on other gears seem to be smooth.

-When I accelerate moderately aggressive, like when starting from a stop light or getting on to the freeway, the car seems to shift from 1st to 2nd gear with a pretty firm shift as if there is a delay. i.e., it shifts after about 2500-3000rpm.

It started happening after I got my timing belt and waterpump replaced. I took it back to the repair shop who did the work and they say I need to get Transmission filter replaced. (I had transmission fluid flush done about a coupld of months ago 92K miles)
Any insight into what could be the problem?

[Eurobob]

my avalon was "confused" on shift points. it would hesitate to shift and shift when it did not normally do it. i had a bad mass airflow sensor with no check engine light. maybe take yours out and spray it with brake cleaner or get a referb unit. replaced mine and all is normal. lots of oil build up in toyotas on the intake side for some reason.