I have a 1996 F-150 that has a blinking OD light. The light sometimes is blinking and other times is not. I had the transmission serviced a while back while the light was blinking and only had the fluid/filter changed because I was headed out of town. It seems to run fine.

I used my code scanner to check for trouble codes but the only one that comes back is a Evap purge valve malfunction that I don't see how that could be related. Is there a separate place to pluge in my scanner to see transmission codes other than the data port under the dash?

The last few times I have driven it, there was a slight clunk when switching from 1st to 2nd. It has not happened often but I did feel it and I am paying particular attention to the feel of the transmission because of the light blinking.

What causes the blinking OD light and how expensive is it to have it repaired. I am a firm believer of having the fluid and screen changed often so I feel that it is in good shape and this is probably a electronic issue. Any help would be appreciated.

Dave

 

The trans has sensors to determine when to shift etc...
A sensor going bad can cause OD blink.
To have a sensor diagnosed and replaced is between $100 - $200.

Ignored and the trans may eventually go South, $1,500 - $2,500.

 

Most code readers can't read Ford transmission codes. If the light blinks a code is stored in memory. You need to find someone with a Ford specific scan tool to read the code and diagnose the problem before you destroy the trans.

 

A t-blink is stored on a call up basis using a higher level scanner but if it results in a CEL lamp as well, it can be read directly with a low end scanner.
I just had that happen and read out a 1746 which was a shorted EPC control valve.
Scanner is an e-READER less than $50.