I have a 2004 4.6 4x4 automatic. trans slips really bad in reverse and will not move. it set a fault p0720 and limp mode. I removed the trans pan to check for metal or debris and found some little plastic plunger. im not sure what it is. if any one could tell me thatd be great. Im a master certified diesel truck tech, so im good with my hands, but I don't know anything about an automatic.

 

think I may have found what the plunger is. it is a dipstick hole shipping plug. so it has nothing to do with my reverse issue.

 

Yea thats just a dust plug. Did you look at the filter? Looks like this person had a clogged filter and pulled the same code.

http://m.f150online.com/forums/showt...316&styleid=17

 

the trans works fine forward, just no reverse. the oil looked metallic and had some small chunks of aluminum in it. ive been looking for a used trans, but cant find one. does anyone know If these transmissions are interchangeable? I have a 3L3P-7000-JA. Ive found 1L3P and 4L3P transmissions.

 

Don't waste your money and time on a used tranny unless you plan on selling the truck immediately. You might get lucky and get a good used one but trust me, it's not worth the gamble. Been there done that, never again!

 

if I could find one cheap enough id probly try it, but so far all the ones ive found have been 7-800$ and over 150k miles. so now my plan is to buy a AODE repair manual and try to fix it myself. I figure its already broken so I cant really make it any worse.

 

I bought the manual and tore the transmission apart. found what was causing the problem. the reverse spring is broken and damaged the piston. now I just need to fix it.

 

 

Kudos for doing it yourself, your saving ALOT of money. What rebuild kit are you planning on going with? Also, it's important to replace (not flush) your tranny cooler after a tranny rebuild/replace so all the debris that's in there won't ruin all your hard work! Good luck and keep us updated on your progress!

 

The only place I found that has the spring and piston is transpartsonline.com so I'm gonna get my kit and other parts from them.