1999 alero ive got the serv eng light on the codes that are stored are 758 and 1860 the tranny is shifting hard.

you need to use a scanner to clear the codes, go to pep boys or auto zone, they will do it for you usually free of charge but if after they are cleared by the scanner and still come up you may have a serious engine or tranny problem. good luck

I had the same problem, wonder if the dynamic vehicle light is on. Or it's hard to start when hot.? If u do try to replace the camshaft sensors, there's 2 of them, that will fix the problem, go to autozone to erase the code the light, good luck

the shifting solenoids inside the tranny will make the check engine light go off. Check the wires leading into the tranny and if necessary you may have to go inside the trans to inspect the shift solenoids. It's odd you do not have shifting problems,. neither did I - yet the wire was broke inside and wound up eventually burning off the terminal to the shift solenoid..
Best regards
Ck

your car is going into limp mode, check your tranny shift control module, or shift position sensor.

Is the check eng light on go to parts store to find out code like poss unplugged air temp at air snorkal unplugged could cause this

It is a problem with the electronic torque converter clutch circuit. inside the tranny

I have a 1999 Oldsmobile Alero and my car was running rough and stalling. Also when the car was shifting, it was making a "thud" sound. My service engine light was on, so I took it to Autozone to run their diagnostic tool. It came back with code P0108 and they advised me to check my vacuum hoses as a possible solution. I looked and found that my air hose running from my throttle body to my map sensor was disconnected. I reconnected the hose and the engine ran normally and didn't make any "thud" sound when shifting. My car is back to normal. So check your hoses. If its still running rough, you may need to replace your map sensor.

Have the vehicle scanned for transmission codes. The codes in the computer will guide you to the problem.

valve body could be sticking.if computer sees a problem with tranny it will go into failsafe mode which means full line pressure this causes a hard shift. there is a repair kit for valves in the valve body

sounds like bad clutches in trans...tranny shop needed...takes 4 qts for a filter change and remember to check it when the vehicle is warm and in park running.