29th Jun 2011, 05:39

I must say that I too have the very same whining sound along with the bucking all the time. I will never pay to fix it, and will just drive the car till it stops working. At least now I know what it is, and not to waste my money on expensive repairs that won't work!

29th Jun 2011, 08:59

Well I'm back to the blog.

I wrote about my 4000 mile trip in Nov 2010. Transmission from time to time shifted hard but made it. I've since taken 3 other long range trips.

I'm not going to spend the money to fix this problem either. It's irritating when it happens and I don't like to every get stranded, so I just keep up with my AAA dues and am hoping for the best.

My 2001 Century is a great road car, getting over 30 MPG and I can move at a high rate of speed without the feeling it's going to leave the road. Good luck to all you Century owners. I'm still wishing that someone who has paid to fix this problem writes in the blog and tells us all about the Borg Warner PCS.

Happy motoring.

8th Jul 2011, 16:11

Hi, I also have a 2001 Century. Two years ago on a trip to Vegas from Canada, I was coming off the freeway and driving at city speeds; my transmission started hard shifting. I shut off the motor for about two minutes, and it worked just fine. I had about 45K miles on the car. I have had this same thing happen from time to time; shut the motor and it seems to fix itself! My car now has 60k miles on it, and I'm still driving it. I think you have to have it scanned to find out the problem.

15th Jul 2011, 15:37

I purchased a 2000 Buick in 2003 with 78000km on it. It now has 165000 on it, and apart from the antifreeze problem at 113000 km, it has been a good car. I have the transmission fluid and filter changed regularly. The car has been used in lawn maintenance work, towing a light trailer. Apart from regular maintenance, it has served me well, and I hope it continues to do so. Just wanted to report my experience with the Buick car. Have not had any transmission or electrical problems so far.

30th Jul 2011, 13:57

If this valve fixes the problem, I sure would like to know where and how to get it, and also the cost.

1st Sep 2011, 20:49

2005 Buick Century transmission shifts hard, and seems to get worse after warming up. The problem is intermittent. Has been driving this way for 40,000 miles. When it happens, I hate the car, slamming during acceleration and sometimes deceleration as well. Took it to a shop, and they saw max gap code and advise rebuilding it. Tried Lucas oil, seemed to help for short while. Just did another transmission flush, with treatment, but the problem is still there.

2nd Sep 2011, 18:29

I had a 2005 Park Avenue with a similar problem. I loved the car, but this was an annoyance. I adjusted my driving to mostly eliminate it (I tried to accelerate slowly) and it usually helped. I noticed it most often when accelerating after coasting at speeds around 20-30 mph. I had the car for about 3 years and 25,000 miles, and it never really seemed to get worse and the transmission never failed. I think the problem is with the PCS valve, and can be repaired without rebuilding the transmission. I never had it diagnosed however, because it was pretty intermittent.

26th Sep 2011, 21:43

2000 Buick Century - "Hard Transmission Shifting". I too, as so many of you others have mentioned, am for the most part, loving my Buick. I bought it 3 years ago (in March of 2008) with just under 80,000 miles, and have had excellent luck and experience driving this car.

I noticed the hard shifting about a year ago (just around 100,000 miles), and noticed the temperature gauge was higher than normal. My first thought was, OK, check the trans fluid and the antifreeze levels. All looked OK, but amazingly, after sitting for a just a few minutes, the situation "resolved itself".

Now, with just under 108,000 miles, I've traveled to Pennsylvania, Maine and other considerable distances (I live in CT) without a problem UNTIL I get off the highway and into local traffic. Even if driving in traffic until I get to the highway, this thing bucks so hard that I originally though the trans was going. I'm not shelling out big $$$$ for a tranny when there's nothing wrong with it.

Now, I pull over (annoying, I know), give it a just a couple of minutes, and it's back to normal driving. It's odd that just a signal from a computer to another component would cause so much problem; there SHOULD be an easy computer "upgrade" for GM to handle this problem...

Thanks, to everyone for their posts : I'm glad it's not too serious a problem and have found an easy "fix" to the problem.

I won't give up my BUICK, I just love the car. Have some of the other issues; the HIGH SPEED or NO SPEED on the fan selector switch (Should be FUN this winter).

Best of luck to everyone with their BUICK... (I'm not stranding our nation - BUY AMERICAN)

13th Oct 2011, 11:54

My first comment was in 2008, & I'm still driving the car, slam shifting & all. After all the comments, I decided to use it until it stops, & it is still going strong, with no fix in sight.

18th Oct 2011, 09:00

The problem is triggered by shifts taking longer than 0.65 seconds. The computer senses when this repeatedly happens, and maxes the line pressure to save the transmission clutches from burning up. There can be many contributing factors; Bad PCS (usually), worn clutch packs means the piston travels further to apply the clutch, thus adding to the accumulator induced time, more seal and bushing fluid loss than when the transmission was newer, foreign matter in the PCS, and an electrical problem with the PCS or wires feeding it, bad sensors such as the MAF, MAP, or vacuum leak sending the computer bad engine load information, which causes it to calculate too low line pressure to execute the shift in less than 0.65 seconds.

What I've learned about the PCS:

1. OEM has a soft steel armature rubbing against a hardened steel bearing, so the armature gets a groove worn in it. The groove catches on the bearing and keeps the part from regulating pressure correctly.

2. The Borg Warner works on an entirely different principle. It is an adaptation of what they use in over 9 million vehicles that use their transmissions. They own the design. It has filters built in, and claim it has no moving parts in the hydraulic area (being an engineer, I don't see how that is possible).

3. I spoke with a facility that re-manufactures and sells parts for the 4T65E transmissions. They uses the Borg Warner for the PCS and TCC and OEM for the 2 shift solenoids. They said they have never had a failure with the Borg Warner PCS or TCC. All 4 are under the side cover, and the parts are inexpensive in the overall scheme of things, to where it would not make sense not to replace them after you went through all of the trouble to remove the side cover to fix the PCS.

I had to replace the PCS at 76,000 the first time, and now I have the same problem at 144,000. A GM mechanic says it can't be because the OEM replacements don't have that problem. I have not found anyone on the web that agrees with that. I don't want to do this again. These are my thoughts and plan.

1. I might not try the Seafoam Trans Tune, because while it may dissolve the varnish, which only typically builds up in the clutch and band area, it puts it in circulation where you will never get it out of the fluid, due to how much is trapped in the converter.

2. I believe the shift kits will speed up the shift and make the harsh shifting go away, but the problem is not enough pressure during the shift, and thus it might slip under load anyway, thereby defeating the protection for the clutch packs. If put in a shift kit, I have a story to tell the new owner when I go to sell. If I fix it the right way, there is nothing to say.

3. Not fixing it at all would probably make the transmission clutches last forever, but it's hard on other parts.

4. Get rid of all other codes other than the P1811. I currently have codes for the O2 sensor after the cat, low coolant sensor, and camshaft position sensor. Then I'll reset the computer by removing the battery cables, pressing the horn, touching the cables together while disconnected, and waiting an hour, so the computer loses the codes, timing information, etc., and starts learning all over. We will see if that fixes it, but I really doubt it.

5. If the above doesn't fix it, pull the side cover, or pay to have it done, replace all of the solenoids using the Borg Warner's for the PCS and TCC, and OEM for the 1-2 and 2-3 shift solenoids. I'm not hard on cars. I drive for good gas mileage. I'm betting there is nothing else wrong in the transmission. I'll be very surprised if replacing the PCS doesn't fix the problem like it did last time. If I'm wrong, I can still put in a shift kit in it to get around the problem, or seethe and drive it like it is.