My 4runner, 150K miles, is sometimes stuttering on the overdrive shift. All gears are strong, overdrive works fine otherwise, no codes or lights. The stuttering usually happens when the throttle is slowly passing the shift point - either up or down. Seems like the transmission can't decide which gear to be in. If I move quickly through the gears shifting is fine. The fluid was just changed, old fluid was not dirty or discolored. Is this a shift solenoid problem? A speed sensor problem? Something else? Advice? Thanks.

 

Did you do a filter change and complete fluid swap or just a drain and refill? I would suggest taking the valve body off when changing the filter and cleaning it as well. It's not hard to do and could solve your problems.

 

My mechanic did the fluid change. I had requested a flush but he warned against it - said the shop didn't do that since it causes more problems than it cures. But, sounds like it needs more involved service than he's accustomed to doing, so I'll either do it myself or get it done. And I'll report back on the status of the problem. Thanks.

 

Yeah he probably drained 4-6 quarts and replaced them. I didn't do a flush either, but I did about 4 drain and refills. The last time I went in and cleaned the valve body and replaced my filter. I had a cel for a solenoid malfunction and it went away about a week after the service.

 

Well, I replaced the transmission filter and did a self-flush, a good idea since I don't know the history of this vehicle. But what solved the transmission "shift" problem? A new set of spark plugs. Turns out it was misfiring when lugging, and it seemed just like a shifting stutter.