Car has a really hard time shifting into 2nd and once it shifts into 2nd smooth 3rd gear shift but once it hits the 4th gear shift it locks up my transmission what is my problem no codes are being shown just a wrench light

 

Auto or manual transmission?

 

Auto

 

I'm wondering if the fluid is low, or dirty and never changed. My transmission was doing some weird stuff because the lead frame was bad, corrupting data going to the computer. The speedometer would drop to zero and car would downshift to first, even at highway speeds. That doesn't sound like your issue though, so I'd start with fluid check and/or change.

There could also be codes that the regular code reader from parts stores won't read. Mine had several .

 

I use my handheld tuner for reading codes and that's what it will do I'll be driving and it will downshift and lock my rear end up I'll check fluid again

 

Also the fluid was changed 2 years ago how often should it be changed?

 

OK, so we are getting somewhere now. The car will volently downshift while you are driving down the road? The wrench light turns on? When this happens, do any of the gauges act up? Does the speedometer drop to zero? Has the odometer every gone blank?

If any of this is true, I think it is the lead frame inthe transmission. About $350 in parts, plus 2.5 hours labor. Check your VIN and see if it is under recall for this. Some 2010-14 F-150s and 2011-12 Mustangs have been recalled. If yours is under recall, the fix is free. If not, about $800 will do it unless you repair it yourself. I had Ford repair my '13 and added my VIN to the NHTSA's complaint list. If Ford ever is forced to recall my VIN, they would have to reimburse me.