23rd Oct 2010, 15:53

I recently have had the the hard shifting on my Buick Century 2000 with 138k, and I don't believe I ever had my ATF and filter changed, so I will do that later in the week.

But it started doing the noise and hard shifting after I replaced my radiator, and forgot to put the auto transaxle back on/tighten the radiator, and turned on the car. Of course lots poured out. I've added some Dex III and called it a day.

The point I'm trying to make here is that it didn't do it till the fluid came out and I've added more. So maybe it's because I've mixed fresh red fluid with dark brown fluid. So I'm just going to replace all the fluid later this week. You know, flush it, replace filter and it should be fine. Maybe...

Oh, I've only had the car for about 10k miles!! I've done all the maintenance we all should do with a used car. Spark plugs, oil changed, fuel filter, air filter, I needed a new radiator and water pump. Also changed a few sensors to turn the check engine light off.

12th Nov 2010, 15:39

Does anyone have feedback on correcting the problem of hard shifting with replacing the PCS with a Borg Warner part? My 2001 Century hard shifts after warming up just like all the others described in this blog. I decided to take the car on a 4000 mile road trip. I'm currently 3000 miles into the trip. Hard shifts from time to time, but still moving along.

15th Nov 2010, 10:40

I have a 2000 Pontiac Bonneville that has the same problem with hard shifting and whining. Question? If the increased pressure is caused by the computer determining that the shifts are too slow, is it possible to eliminate the call for increased pressure from getting to the PCS? Could this be done by a program in the computer or a disconnect of a connector to the transmission? I am not transmission smart!

Just a thought. Does anyone know if it is possible?

18th Nov 2010, 05:25

November 18, 2010.

I too have a 2000 Buick Century and have had the trans replaced twice. The problem reoccurs after only a few hundred miles.

I thought I was the only one with this problem. Now I will drive it into the ground. I will provide good maintenance practices and use suggestions gleaned from this site regarding additives, battery, and fluid levels. I love the car and I do regular motor maintenance on time.

Thank you to all of you for your comments. I was making arrangements to have the trans rebuilt again as I am retired and cannot afford to buy another car that might have worse problems. Decided to do a little research on the transmission and found all of you.

Thank you. Thank you.

18th Nov 2010, 18:10

I've heard putting a shift kit in the trans will prevent the problem, since a shift kit makes it change gears faster. But I believe the PCS solenoid can still go bad. But a shift kit compensates for it, and the computer doesn't notice it.

17th Dec 2010, 23:51

Purchased a one owner 2000 Century Custom on 8 November 2010. It was previously owned by an elderly couple (verified) and had 40562 SOFT miles on it. It drove great for the first 10 days or so, but then the tranny started shifting hard into the upper gears. It doesn't happen every day, but when it does happen, it's annoying. You wouldn't think a car with less than 41K miles on it would have tranny problems. I am gonna try the spark plug change first and see what happens. Sad that it has this problem, as the car is otherwise very nice. This will probably be the only Buick I will ever buy. Too bad GM/Buick didn't/ wouldn't come up with a recall fix that works.

13th Feb 2011, 11:41

On a 2000 Buick Century or any Buick it's very important that you change the automatic transmission fluid and filter on time. Meaning what the owner's manual says; the 2000 Century, it's every 60,000 miles. Most people never change them at all, hence all these harsh shifting problems in 1ST to 2ND gear at low speeds, and other problems on dirty oil.

Many are changing the pressure control solenoid in the automatic valve body, and a repair that may not be needed and a wasted $400 to $500 repair bill in a trans shop, where they also change the fluid when they do that repair. I would stay away from flushing an automatic unless they drop the pan and change the trans filter, which most the time they don't, to make a fast buck with little labor.

It's important you change the trans filter. I learned this the hard way, I ran my 2000 Century to 80,000 miles, which is 20,000 past the trans service, and at low speed it started jerking a shift really hard, or a clunk or whatever you want to call it.

I went to a drive thru lube place where you stay in your car while they do it, had the transmission fluid and filter change for $84, 2 weeks and 200 miles of highway driving, the jerking or clunk went away, and it shifts smooth again. I think this is what happened, the pressure control solenoid gummed up in the valve body along with other parts, and the hot new fluid cleaned it over a 2 week time, and took it thru the new filter, where it cleaned the new fluid/oil. The transmission runs great now.

5th Jun 2011, 09:55

My 2000 Buick Century is having transmission problems, too. I might just get rid of it. Worst car I have ever owned!

7th Jun 2011, 02:06

Hello all,

I would like to say thanks to everyone here for making me feel a bit at ease. I recently bought my 2000 Buick Century for a little less than $2000 out the door. As in recent I mean this month. A bit pricey, but considering the car market, it seemed like a good buy.

I must say besides the transmission issue, this is by far an AMAZING vehicle. It is a very gentle, powerful, and comfortable ride.

I noticed the transmission issue the second day. I wasn't angry because I bought it as is, but it would've been nice if as stated before, GM made right on their error. I don't have a lot of experience with the vehicle, but this happens when the temp. gauge is around the 1/2-3/4 mark, give a little towards the warm side.

The only other issue is the fuel gauge didn't work.. but I have been using the trip.. it seems to get about 25 MPG combined.

Since viewing this topic, I probably will not put much money into this car, since they seem to still be running mechanically even with this problem.

I'm going to baby the car for the most part.. which isn't so bad, since I may have a little bit of a lead foot and we all know fuel is pricey. There's a lot of nice insight on this site, and I look forward to checking out possible future used cars I buy on here. Thanks everyone for an ease of mind.