ford E450 Tranny down shift to 3rd and speedometer goes to 0.

[whiteva]

Cruising along 60ish tranny shifts down to 3rd gear and speedometer drops to "0". I can continue in 3rd gear until safe to pull over and stop, then everything returns to normal. This happened twice on a recent trip, once on the way out and once returning.

Anyone else had this problem?  Tranny is a 2007 7c3p-7000-hc    5 speed on a Ford E450.

Vance

 

[Lou Schneider]

Sounds like an intermittant connection or a bad vehicle speed sensor.  It's located on the right side of the transmission near the output shaft. The transmission staying in 3rd gear is "Limp Mode" so you can safely get to a repair shop.

Try opening the connector and cleaning the contacts - if that doesn't fix it you'll need a replacement.

You should also see a trouble code thrown on the OBDII port.

 

[Utclmjmpr]

Just look at the great mileage your getting .>>>D :

 

[whiteva]

Thanks Lou. I agree with you and may just clean contacts and replace the sensor. 60 + K miles time for fluid & filter change anyway.

Cheers

 

[whiteva]

Very late addition to this thread: The problem WAS the speed sensor. That sucker is located on the very top of the tranny. I could get to it but it was awkward and stuck solid. Rather than drop the tranny, I pulled back the carpet and cut a access hole directly above the sensor. 15 minutes & the new sensor was in place along with a nice patch securely fashioned. Additionally I installed a new dipstick pipe fashioned out of stainless to replace the original one that was badly rusted inside. Prior to this, every time I checked the fluid level, I would notice rust on the dipstick. Estimated time to copy the old tube was about an hour.

Finally I took the rig to my local tranny place for full servicing.