Someone who knows what part this is?

[Frank.Daltveit]

Struggling with a flashing overdrive light.

Maybe a broken speed sensor? The car shifts to 4th gear, but it seems like the flashing overdrive lights comes on right after the car shifts to 4th gear.

Is there anyone who can give me an explanation of what A and B on the picture below is?

http://www.flickr.com/photos/67559747@N02/6149593297/in/photostream

 

[Lube]

For the flashing OD light, take it to a tranny shop and get the codes pulled. The scanners that you get from a parts store won't do these.

I believe that "A" is a speed sensor
Can't see "B" well enough to tell.

 

[drdoom]

B is the Vehicle Speed Sensor for your speedometer, and A is the rear sensor for the transfer case.

 

[Frank.Daltveit]

For the flashing OD light, take it to a tranny shop and get the codes pulled. The scanners that you get from a parts store won't do these.

I believe that "A" is a speed sensor
Can't see "B" well enough to tell.

I get a code 646 - Incorrect gear ratio-fourth gear as the fault code. I've heared thas maybe because that the speed sensor is broken. Any ideas?

 

[Frank.Daltveit]

But is B the input speed sensor?

 

[drdoom]

But is B the input speed sensor?

I am not positive, but I think B is the VSS Vehicle Speed Sensor. Post up some specs on your truck i.e. engine, transmission, year & model. I may have a photo of some 5R55E sensors.
BTW, P0646 is A/C compressor clutch relay circuit low.

 

[joecrna]

Agree, "A" is the transfer case sensor. We do need specifics about your truck.

 

[Frank.Daltveit]

I have a 1995 Explorer 4.0l with automatic transmission

 

[ranger7ltr]

Check this link for more info...

http://www.fordpartsgiant.com/diagrams/large/350/p23426.png

The page is enlargeable by clicking on it... If you look at the transfer case the item 9E731 is the speed sensor for the ECU and speedometer... I believe the other sensor in your pic is the 4X4 indicator...

You can use www.fordpartsgiant.com for more info on the truck...