My 2005 FX4 is throwing the codes PO722 and PO720. When it threw these codes it barely pulls in reverse. Are the codes the cause of the reverse problem?

 

I don't think I have ever heard of a code being the cause of a specific symptom - other than psychological frustration and or panic. Lol. - couldn't pass that one up.


On a more serious note, I am not aware of any 'limp mode' or any power limiting logic associated with output shaft circuit integrity or speed.

 

I knew it was a long shot. I'm sure it's a bad tranny.

 

If that means it slips or revs, regrettably I'd have to say you're right.

 

Hoping you are still on the forum. My son is having the same issue with his F150. Replaced the OSS and still the same. What was your final outcome.

 

Both codes are telling the speed sensor is not generating any signal.
This would not be related 'directly' to the transmission.
You may have a second issue or even a harness issue that would be common to both.
Good luck.

 

Thanks for the reply. Advance auto originally gave me the wrong sensor, so I used it - it was for the sensor directly in front of the OSS (VSS?). No code now, but haven't really driven far- reverse is still slipping. Going to change the trans filter and fluid tonight. Can't wait to see what is in the bottom of the pan. Fluid is pretty dark

 

I finally got a chance to drop the pan and the fluid was quite fresh looking. Nice ruby red. Bad news. Lots of of metal pieces. Is this going to be the reverse band chewed up or is there any thing else that would get chewed up. In any case, I can do most work, have decent tools and area to work. Just not a lot of time. How difficult/amount of time to do the work if it is just the reverse band. See the pics. I grabbed a 10 mm wrench because my son took my tape measure. This truck only has 85,000.

 

Look closely at the debrey.
Is it from the sensor?
It it magnetic or nonmagnetic?
Reason I ask is if it is thought they came from the converter Torrington bearing breakup and have circulated pieces throughout the rest of the transmission and the front pump/converter.
The trans would need to be disassembled thoroughly, cleaned and blown out to get anything left in place.
Also the radiator cooler and the AUX cooler should be hot reverse flushed for the same reason.
If anything it left, you stand a chance of failure again from anything left in.
Good luck.

 

The pieces all were magnetized to the tip of the screwdriver, but I thought it was from being attached to the magnet in the pan. Thanks for the advise on the radiator cooler and aux cooler flush. My son is going to call around today for pricing. I'll tell him to ask to include the flushes.