Need transmission advice

I have a 1991 Chrysler TC by Maserati with 44K miles. The transmission won’t shift to a higher gear from low. Occasionally it tries to shift but goes into neutral. Does it necessarily mean a new transmission or could it be possibly repaired?

I see by the year the car has passed the warranty by a couple of years. With 44K, unless you are in the habit of smoking up the tires at every other stop sign, the transmission should be pristine.
Do this, take the transmission dipstick out and smell it. It should smell like nothing. If it smells like anything, and especially if it smells kind of burnt and acidic, your transmission is cooked.
I think it is anyway, based on your description.
It’s a young car, so you should spend the money to change the tranny. Then stop lighting up the tires.

Ok - 44k or not a 20 year old transmission is not “pristine.” Has it ever been serviced or does it have 20 yr old fluid in it? That’s no reason not to check it but either way it isn’t young or pristine.

You need to have a transmission shop put it on a scanner & pull out any error codes that are present. Find your best local, independent place and avoid the national chain type shops. If you get diagnostic info you can post it back for comment.

Is this a 3 speed or a 4 speed automatic? Is the fluid level up to the full hot line? Are there any signs of transmission overheating i.e. burnt fluid or overheating engine coolant?

As ‘cigroller’ replied, run this by an independent automatic transmission shop for a scan if it is a 4 speed transmission or a diagnostic if a 3 speed transmission.

Good luck on this