Automatic transmission has high pitch whine and won’t change gears correctly. Turn off car and restart and it runs perfectly. Diagnostic doesn’t show any think wrong. Happens about once/month Any Ideas
When exactly does it whine??? Does it whine on start-up? While driving? When cold? When hot? After sitting overnight? How is the fluid level/condition? Check level with engine/trans hot, on a level surface, and with the gear selector in “P”. Give some more info.
I believe Transman already knows this, but I’m going to suggest it anyway. He won’t guess at a problem like I will. That’s the difference between a non-tech and a PRO.
The harsh shifting and the whining noise from the tranny (only on the upshift) is caused by a faulty/dirty pressure control solenoid.
My 2000 Silo has been doing this on and off for three years.
The first time I noticed it, I took the van to my local independent tranny shop and after a short test drive, the van was put up on the hoist and the tranny fluid and filter changed.
It ran fine for almost a year and a half after that bout and has acted up periodically since.
Like you said, run it/acts up. Shut it off for about 1/2 hour (let everything settle) and start it up/runs fine (sometimes for months) until it unexpectedly acts up all over again.
The valve I mentioned wears out eventually and is located inside the tranny.
The valve is inside the tranny and I don’t expect to drive this one much longer so I’m not putting any more money in it.
Transman, the whine can start at any time as I’ve found it doesn’t matter whether it’s hot or cold.
First started when I had it parked on a 30 degree incline and started home. Have had transmission flushed and a solenid replaced. $750 so far. When it starts to whine, it usally is after a stop light and idleing for a while. Cut off the engine for just a second and start up again an it is fine. It has been running fine now for several weeks but you just don’t know when it is going to do it again