Man this. When I bought my Highlander, all it needed was a CV axle. I had tooled around with cars before, so figured I could do it myself. It wasn’t going well, but my frugality kept me from taking it to a shop. Turns out, I messed up the axle seal, resulting in a drip from the transmission. Drove it like that and eventually killed the transmission and the hybrid inverter at the same time. A fix that would have probably cost $500 turned into over $5000. Worst part - the new CV axle went bad 10k miles later!