Transmission Problem Ford Escape 2002

I have a 2002 Ford Escape, I had the transmission rebuilt 12 months ago. Just recently the o/d light came
on but was driving fine. I took it to the Ford Service Centre to get the codes read.
They told me that the connector that went onto the solenoid plug had been broken and they tried to fix
it. Since then due to the bad connection after they tried to fix it, I now have intermittent gears..
sometimes reverse only, you play with the plug and you my get it to take off in 3rd gear.
As Ford found the broken connector,   I assume this was broken when the gearbox was temp fixed and
sealed with silicone to hold it in place. Problem being everytime I hit a bump the o/d light would come
on.
Ford have told me i have to replace the entire wiring harness in my car -  which is not going to be a
cheap fix.  I would like to know if I was to get a new solenoid unit, (both connectors have been broken)  
am I going to be able to buy the connector to go onto the tranny solenoid and does the gearbox have
to be taken out to put the solenoid in?