CarTalk.com Blogs Car Info Our Show Deals Mechanics Files Vehicle Donation

Ford F250 Automatic Transmission goes out of overdrive

I and a friend both have 1997 ford F250 Diesel pickups and both at about 140,000 miles have had problems with the transmission going out of overdrive and changing gears at higher than usual rpms. The overdrive light blinks and if the pickup has a day or two it will reset the computer and function normally. Any suggestions…a fix easier than a new transmission???

Did either of you ever service the transmissions? Have either of you at least checked the fluid for level, color, smell?

The blinking O/D light means the computer sees a problem. After that it is probably shutting down certain functions like torque converter lock up and perhaps even higher gears. It does that the prevent further damage.

What you need is a good, local transmission shop to scan it for error codes. Is the check engine light on?

The TCM detects a fault and flashes the OD light to let you know. Get the TCM scanned to retrieve the code and see what it is saying is wrong. If the OD light flashes, the first thing the TCM will do is drop out of Overdrive to try to prevent damage to the transmission. Even if it is not flashing at the time of scanning, the TCM will retain the codes for retrieval.

My friend had his transmission serviced by Ford and of course they wanted to sell him a new one for 4 thousand. The Ford manuel does not have recommendation to change or service the fluid…I have driven my pickup in town, and only after about a hundred miles of highway driving will it begin to blink, it has done this for a year or so and otherwise it drives well. Is there a heat sensor which is the problem?

The check engine light has never come on…

So it sounds like you never serviced this transmission and that its mostly been town/city type driving. In that case my gut tells me that its a goner.

Find out from your friend exactly what Ford found when they checked the transmission.

If it was me I’d take it to a local, independent transmission shop and ask for their recommendation. It might not seem right but a dedicated transmission shop is typically much better equipped to deal with a transmission then is a dealer service dept. A lot of dealer shops won’t even have a real transmission specialist around. All they’ll have is people who know how to price a new one, and then others who know how to pull one out and put another in.