olds 98 not shifting past 2nd
i have a 93 oldsmobile 98, loaned to my brother he brought it back today. said low coolant light came on then car wouldn't shift into overdrive, said acted like wanted to die when it should be shifting into overdrive unless he hit the gas. I drove it myself to see what he was talking about, shifted fine, low coolant light came on then didn't shift past third. drove it to part store added coolant, noticed on the way home it wasn't shifting past 2nd. not sure if I need to be looking at a shift solenoid or if he messed something up shifting manually from 1-drive. any ideas or information would be helpful. experience with transmissions is slim beyond replacing.