2000 century hard shift pattern

for about a year now our 2000 century has a weird thing it does usually after about an hour of driving the shift pattern gets real hard and at 35 and 45 and 55 you feel the tranny jerk hard.. the weird thing is it does not do it everytime it is driven , but about 3/4 the time... also service engine light came on and reading said misfire cylinder one.. anybody have ideas as to either problem????????
ps i already tried changing tranny fluid abnd filter.. no go..

How many miles are on your Century? You probably got a P0301 DTC error code which is misfire cylinder #1 which in turn triggers the SES Mil Light.

The 4T65E tranny is sensitive to engine conditions so it is best to resolve known engine issues first. The best starting point would be replacement of the spark plugs and ignition wires.

for about a year now our 2000 century has a weird thing it does usually after about an hour of driving the shift pattern gets real hard and at 35 and 45 and 55 you feel the tranny jerk hard.. the weird thing is it does not do it everytime it is driven , but about 3/4 the time... also service engine light came on and reading said misfire cylinder one.. anybody have ideas as to either problem????????
ps i already tried changing tranny fluid abnd filter.. no go..

yes!!!!..same exact thing with my parents car!!..but they parked it back in late 03..with 324,000 km's..were gonna get it going good again.., but dont know how to fix that tranny problem.whats the most mileage anyone has ever gotten on this car?...just curios

oops...just read everything in a previous thread about this problem:iceslolan kinda sucks..but it's really nice to know now..thanx guys!!

for about a year now our 2000 century has a weird thing it does usually after about an hour of driving the shift pattern gets real hard and at 35 and 45 and 55 you feel the tranny jerk hard.. the weird thing is it does not do it everytime it is driven , but about 3/4 the time... also service engine light came on and reading said misfire cylinder one.. anybody have ideas as to either problem????????
ps i already tried changing tranny fluid abnd filter.. no go..


dude i am having the same problem. u start driving and all of a sudden the engine makes this noise like a cat or something. you take the car off for 10 mins it goes away. i have no idea what it is. took it to cottmans and they could find nothing wrong with it. they said it could need recalibration which could only be done by GM. spoke spoke to my dad about it he thinks it could be the torque convertor in the transmission. also said it could be the linkage cable ( this is cable allows the gears to be changed) needs to be adjusted. i am going to another shop to have it diagnosed. please keep me informed if you find a solution to this.

You might read through the thread called "2000 Century Harsh Shifting when warm" and see if that fits. It seems like a common problem on the 4T65E tranny. If so, its the PCS solenoid sticking. Bottom line is about $800-$1500 to replace the PCS if done in a shop, and from some of the responses of those who have done it it may not be a permanent fix. I started that thread and still have the problem - When it starts singing to me, I expect hard shifting. I'm just living with it. The car has 105,000 miles on it and I will probably keep it as long as it still runs.

ttt thanks all for the responses . yes it does make that strange noise right before it starts shifting hard.. and does not always do it.. very freakin weird.. wish their was a sure easy fix......

ok i took it to a shop today a friend of my dads. he said that its the valve body in the transmission that needs to be replaced. said its going to be a 1500 dollar job to do. he didnt even bother to test it cause he knew exactly what i was talking about.

ttt thanks all for the responses . yes it does make that strange noise right before it starts shifting hard.. and does not always do it.. very freakin weird.. wish their was a sure easy fix......

You may be able to minimize the effects of the harsh shifting and baby it along. Try some tranny additive such as Seafoam or Lubegard. It may not cure the problem but you have nothing to lose at this point.

I recall someone with the harsh shifting and whining sound make it to 160K miles and it still runs. Problem developed at 80K miles. You may have to stop and turn into a parking lot to turn off ignition and wait awhile to reset but it is better than nothing.