I can't back up!

I have a 2000 Quest and for the past 3 years the car will not go into reverse intermittently until it is really warmed up. COld weather makes this worse but it happens in the summer as well. Mechanics have changesd the transmission fluid, done “cleanouts” etc but none seem to have any answers except replace transmission or get new car. Any ideas?

They’ve done just about all the cheap stuff you can do. I don’t know if the solenoids (electronic valves that control the transmission) can be removed and replaced without removing the transmission. Rebuilding the transmission may be the only option besides selling.

There is usually no electronic components to reverse application. It is controlled exclusively by the manual spool valve so make sure that the manual cable adjustment is spot on. The fact that the failure occurs when the transmission is cold indicates it might be a leaking seal that will expand under thermal expansion and pressure application. How many miles on this transmission? Has it done any towing?
If you keep cycling from neutral to reverse can you get an application?

About the only test a transmission technician can do is a pressure check emphasizing reverse to see if there is any problem with the pump or pressure regulator. Sadly, he will have to see the problem occur before he can do any diagnosis.

Hope that helps.