overdrive issue 1997 psd.

[ffxstc]

read about 20 pages and haven't seen this problem. 1997 f250, 162k, everything seems perfect on this one owner truck I picked up last night. 40 miles into my interstate trip the overdrive kicked out. slowed from 70mph and 2000 rpm to 55mph and 2500 rpm. when I started down a gradual grade in about 20 miles seemed like it wanted to go back into overdrive. hitting the overdrive button did nothing..hit a bump and it went back into overdrive. slowed down to about 60 and 1800 rpm for remainder of about 60 miles. now I'm freaked out. going to check loose connections as I thought maybe the bump in road loosened a connector. my first power stroke truck...always had dodges....any help appreciated, thanks

[madpogue]

Are you sure it's actually downshifting, and it's not the torque converter unlocking? You mentioned hitting a bump; maybe there's a short or a chafed wire somewhere, causing the brake lights to come on (or the switch out of adjustment), which unlocks the TC.

[ffxstc]

well, the overdrive off light on shift lever comes on, and then you push button and it wont do anything, just light staying on and not going into overdrive.

[madpogue]

That sounds more like the wiring to the OD button, or the button itself. Any looseness in the column, or funny noise from the column when you steer?

And the OD-OFF light is lit up steady, not blinking, right?

[ffxstc]

steering wheel squeaks as you move it from center steering to right or left side. I beleiev I have narrowed it to a wire(s) as everything functions unless I hit a big bump. That is when overdrive will either turn off or on. Speedo needle will get a little flutter at 70 ish

[ffxstc]

light is steady either on or off...no blinking...thanks