2001 Toyota Highlander won’t shift out of first gear

my toyota 3.0l engine wont shift out of 1st gear constant rpm at between 6500 & 8000

Older Highlanders not upshifting at higher speeds, say 45 mph, is somewhat common but that doesn’t sound like what’s happening with yours. Have a good independent transmission shop look at it. Bear in mind that we’re talking about a vehicle that’s nearly 20 years old and it may not be financially worthwhile to fix. Transmissions aren’t cheap and a 2001 Highlander typically goes for $3-5k. And avoid running it with the RPMs that high in the meantime. It’s not good for the engine.

took it to a transmission shop found out that whoever owned it previosly had not hooked the main ground wire back up to the transmission therefore cause the transmission to go bad

So I assume reconnecting the ground wire didn’t fix the problem. Sorry to hear it.

How long did you drive it that way? Did this behavior occur during your test drive?

No it didn’t do it till about a month after I bought it. Drove it less than 10 miles after it started shifting hard then not shifting at all. This vehicle was not a good vehicle from the day I bought it. We had to replace every single sensor on it. Due to codes. Then discovered that all brakes rotors and calibers were rusted almost all the way thru. Then the transmission issues. My mechanic shop did the repairs. Except the transmission the vehicle is currently setting

Then the mechanic’s explanation doesn’t make much sense. The transmission may be shot but the missing ground wire explanation does’t fly. Unless it was the mechanic who accidentally left the wire disconnected after replacing a sensor.