Do I want to replace my transmission with a NEW or rebuilt transmission?Mile169k

What is your question?

Just took my 2002 Camry XLE with 169K miles to mountains. Hit 4000feet & car transmission started slipping "Bad". Was losing speed, so I downshifted into 2nd gear. Made it to destination of 6250feet-but barely!! Tried driving home,20 minutes down mountain- Camry was like it was in neutral-not in gear-but it was in drive, RPMS were up to 7000 & was not shifting!! Pulled off road called for tow. 2 weeks prior before going to mountains,I tried reversing Camry & it wouldn't engage the gear-like it was in neutral. How do I know at Transmission Shop if it's a: shift solenoid, needs a rebuilt transmission, a new transmission, or something else in the transmission.Camry has been serviced & maintained Excellent-Like new!!