Son has this car and it Jumps out of 5th gear at about 45 and higer, is that a synchronizer or shifter fork? Told my son since it is pretty much a junker, under $1000 car just tie a bungy cord to it when he has it in 5th. Or don’t go on the highway with it, use it in town so it never gets into 5th. 40 mpg is why in town.
there is a problem inside the tranny ,what it is i don’t know. the only thin i can think of is find a used gear box if you want to use the can on the high way. check the oil level in the tranny before it burnns it shelf up
The car isn’t worth repairing.
Buying a used gearbox is risky.
Keep driving it and avoid 5th gear.
Could be a synchronizer assembly problem, shift fork, or a combination of both.
You might ask your son if he has a tendency to drive with his hand resting on the shifter. That can lead to problems like this mostly due to shift fork/synchronizer sleeve wear.
Any repair would be pricy so it’s best avoided. An alternative might be to continue driving the car until when and if it needs a clutch while keeping an eye out for a good used transmission on the cheap and then swapping the trans out.
That’s all assuming the car would be kept for a while, etc, etc.