1986 Buick LeSabre Estate Wagon with Oldsmobile 304 with a TM200-4R

[Bradley Sawicki]

Help me out here, my vehicle starts up fine and if i put it in gear it will run 0 to 105 and maintain that speed for 20 or 30 miles. Then it starts to slow down and ends up in second gear not able to go over 35, put it in park and it has full range of throttle. Cut the exhaust to make sure it wasn't struggling to get air out. So i am thinking its a solenoid or maybe a bad torque converter. Anyone have a similar situation ?

 

[HotZ28]

Are you talking about 105-km, or mph?

 

[G-750971]

Are you talking about 105-km, or mph?

MPH I have my GPS on my windshield, which shows speed .