Hello. I have a 1992 jeep Cherokee sport 2wd. Starts and runs good after about an hour of driving around I start having shift problems it will not shift out of first gear and acts like it downshifts it doesn’t matter how much gas I give it it will not go anywhere and acts like it wants to stall out. When I turn off the engine something sounds like it’s boiling. Any suggestions would help. All fluids are topped off and vehicle does not overheat.