Originally Posted by madbomber08

We own a 1989 toyota camry with 200,000 hard miles and it has a similar issue as you are having with your 4runner. Driving at any speed, fast or slow, it will sometimes shift from o/d to 3rd iradically and vice versa. Sometimes we can be driving it with no troubles at all. It will shift and stay in o/d for the duration of the trip. Other times it is annoying and will stay in 3rd. The car has no RPM gauge so we feel as if we have to go 45 or less when it shifts down to 3rd because the ole girl sounds like shes revving way up there.

A few years back we replaced the ECU and ECM (if i remember correctly) because that is what the transmission tech. told us to do. It did nothing. We flushed the tranny, too. He couldn't figure it out after that and we really didn't want to spend any more money on an old unsafe beater. My cousin, who's a GM mechanic, thought it to be a shift solenoid. He doesn't want to mess with a *Toyota* though. She still runs great around town though, just not a highway driver.

Anyway, I just thought I would throw that out there. I know it's not the same vehicle and maybe even not the same problem. But I will keep following this and see if you figure it out because this is interesting.

Originally Posted by bmcel

My A340H (3VZE auto) does the same thing intermittently and up until recently, had no obvious causes. It has become more frequent over the last few years and I just recently noticed that it's beginning to react to the throttle position occasionally. If it starts downshifting/upshifting between 3rd/4th and I let of the throttle just a hair, it stays in 4th. This is not always the case but seems to be consistent enough to be related. I haven't tested the TPS yet but am fairly certain it is the culprit and will post my findings hopefully tonight.

Originally Posted by kcorpetti

Although it does sounds like the same problem, I'm also noticing my Torque Converter locking and unlocking up. You should see a 300-400rpm change at around 40+mph. If you have that same problem, then welcome to the club! If not, you're lucky! 3rd/4th gear misshifting probably is a bad solenoid that can't hold up once pressure rises up. Try getting your valve body and solenoids checked.

Originally Posted by moutainman4life

so no one has figured any thing out on this becouse a freind just bought one and its doing the same thing

Originally Posted by milowilli

I think I am on to something.. The tranny speed sensor is not reading..weak magnet I assume. I ordered a new one..waiting for it to arrive to install. The magnets go bad with age..80s vintage. Will let you know how shifting goes when installed.