anbsmum -- When some on in authority "yells" at a subordinate, that show poor leadership skills. That being said, it can also be construed as Bullying and Harassment. Especially if you are the only one being yelled at. That's disparate treatment. Normally something that should be grieved, but as you are in you probationary period ( 90-work days or 1 calendar year ), you are pretty much at the mercy of manglement. But still contact the office steward, of if none in the office, contact the Assistant District Representative and tell what is happening in your office. The ADR might be able to file a class action if the PM is bullying or harassing others in the office. Document, document, and document. Ask others if they would submit written statements of what they have seen or experienced. The office should have USPS policy statements on bullying and harassment posted on bulletin board(s) in the office.
"you need a smaller SUV" -- definitely get the ADR involved on this issue!
-- To be sure, I have NEVER heard of a PM or supervisor telling a carrier that a SMALLER vehicle is needed!! That is one for the proverbial "books".
-- About your vehicle -- what year and make is it?
-- Why is your spare tire in the back of your SUV? Where would it normally be?
-- Possibly your PM is concerned the spare tire could be a "missile hazard" in the event of an accident, but apparently is not concerned about the trays of mail or parcels becoming missile hazards.
-- Did you drive your SUV at the academy or during LLV training? If so, did any of the instructors comment about it or its size?
-- If the ADR can not intervene, tell the PM that you are looking for a replacement vehicle ( wink, wink ) and hopefully she will be gone soon.
-- Do as "Shafted" suggested -- politely ask for the PM's mandate in writing in front of witnesses.
" She’s called me multiple times on her day off while I was on the route to ask where I was on the route. "
-- Mention that to the ADR as that could certainly be harassment, especially if the PM was in an off-duty status.
-- Why does the PM have your cell phone number? It should only be used for emergency contact. Change your number and keep it to yourself.
-- The next time you are "invited" to the office, bring someone along to ward off any "the RCA said, the PM said" situations. If the PM won't allow someone in the office, have that person stand outside the office -- with in hearing distance.
-- If the PM does not allow you to work, might as well head to the unemployment office. A lot will depend on your state's rules for collecting unemployment. Might raise some interest when you tell them the reason you are not working is that the PM said to get a smaller vehicle and won't allow you to work until you do so. Someone in the office just might contact the local media for a human interest story. Who knows?
-- In the mean time, if allowed in the office, do as instructed ( aside from getting another vehicle ). Manglement can fire you for just about any reason they can think of during your probationary period. Don't give any reason to do so.
-- Good luck.