2000 Buick Century from North America - Comments

I changed my trans fluid in my 2000 Century before going on vacation. Used some Mercon V stuff that is supposed to be good for all vehicles.

Turned off the interstate and as soon as it started down shifting, it would snap your head back violently and whine. The Mercon is thinner than Dexron III.

I put in some LUCAS transmission additive. It is very thick like STP or something. It seems too thick to be putting in the transmission. I would mix it with trans fluid first if I were going to add it. I put in most of a bottle and got some relief. It will make your hard shifting better. Use at your own risk though, I am relating my experience.

I tried other things; changing the filter and fluid again without the Lucas; no good. It seems to be a function of heat, so I wired my cooling fans to both run all the time the key is on. (That makes the air conditioner work much better in town.) Same problem returns when heated up to normal.

I am going to try the Trans Tune next. If not better then, I am going back to the LUCAS stuff. It definitely smoothes it out.

From what I've read, even rebuild is not a good fix. Design problem there somewhere with that PCM deal.

I found the fix to the ABS problem. It is the wiring harness rubbing against the transmission or/and air conditioner dryer. Cable tie it back away from both.

My fuel gauge went out too. Must drop tank and replace unit. Cheapest place is for that ebay.

These cars should get 30 MPG. Mine is sucking because of this transmission deal (20-24MPG).

I think the GM's were much better made in the 90's. My 93 and 94 Park Avenues and 91 Grand Prix were great.

I have a 2000 Century which I put Mercon V trans fluid in and it went from bad to worse.

It is thinner than Dexron.

Adding Lucas transmission additive makes it shift smoother.

Maybe someone reading this can use this to get their car good enough to sell.

There is definitely a design problem and the car may not be worth trying to fix with a rebuild.

It might happen again.

I will try the Trans Tune product from Sea Foam company on mine though.

Well, everybody had to learn the hard way. My Camrys have all been trouble free.

Well, there are plenty of Camry owners on here that don't share your sentiments. I know, they're all fake. Personally both of my Buicks have been great cars and far more comfortable than any Toyota could dream of being.

I tried the Trans-Tune and Trans-X both and they seemed to exacerbate the problem. It may work for some people. Had it worked, I'm sure it would have been a band-aid fix at best.

It is a problem with those solenoids in the trans.

I did manage to trick it out though and make it work much smoother by pumping out 1 gallon of fluid and replacing it with 50/50 mixture Dexron VI and Lucas Trans additive.

The shifting is much smoother now.

When it acts up again, I will do the same thing again. It is about a $32 job including the $7.50 handheld suction/evacuation pump available at Harbor Freight stores.

That is my band-aid fix.

I have a 2001 Buick century, my car slams into gear also although it drives great on the highway. I will not spend money on fixing it im just going to drive it till it dies RIP live and learn.

My GF's brother has this same problem with his 2000 Buick Century. Today he brought it over we added approx 3/4 QT of dextronVI (in 2 intervals) first interval, added approx 2/5 QT and showed significant improvement in this "bang shifting" (which ONLY happened during takeoff from a dead stop with hard acceleration).

After a short test drive (several starts/stops with hard acceleration), brought it back to my house and added remaining 3/4 QT of dextronIV, took it for second test drive, 2 MILD "bangshifts" and it stopped entirely for the remainder of drive (several starts stops with hard acceleration), he called after he drove back to his house and said he drove it hard and with no problems (approx 10 miles).

A note - the positive terminal on the battery was unplugged both times - for 15 minutes and 45 minutes respectively. This should reset the ECM, I'm unsure if this had anything to do with it.

The transmission is now slightly overfilled (approx 1/16-1/8") above the "safe fill" mark

I recently purchased a 2000 Buick Century with 150,000 miles on it. It ran great for the first couple of days and now it is having the same "hard-shift" problem and whining that everybody else seems to be having.

Also, I have the same temperature problem. Has anybody tried replacing the thermostat? When my dad was flushing the radiator, he told me that he didn't even think the car had a thermostat in it. A thermostat isn't much, but it's just one more problem to add to the growing list with this car.

I will try the suggestion mentioned a few posts ago about the Trans Tune/disconnecting the battery for a while. The problem does go away after the car is shut off. I think this sounds more like a computer problem than a transmission problem. But, I am not a mechanic. I am taking my car to the shop tomorrow to get the CV shafts replaced. I think it's absolutely ridiculous that GM isn't recalling this being that this whole entire thread is dedicated to the same problem. I did find a pretty recent recall that I have listed below, so maybe there is hope for us yet. If my mechanic tells me anything that I haven't read on here about the hard shift problem, I'll be sure to pass the information along. This is my first and most definitely my last Buick. I'm sticking to Nissan.

Recall ID # 09E005000 - STEERING - Hide Details

Recall Date: FEB 17, 2009

Component: STEERING

Model Affected: CENTURY

Potential Units Affected: 979.

Recall Date:

FEB 17, 2009.

Model Affected:

2000 BUICK CENTURY.

Summary:

DORMAN IS RECALLING 979 STEERING KNUCKLES, DORMAN P/NOS. 697-902 AND 697-903, SOLD UNDER DORMAN'S "OE SOLUTIONSTM" BRAND NAME, AND NAPA P/NOS. 7-8502 AND 7-8503 WHICH WERE SOLD FOR REPLACEMENT USE ON THE VARIOUS VEHICLES LISTED ABOVE. A POTENTIAL MATERIAL OR DESIGN DEFECT COULD RESULT IN THE STEERING KNUCKLE BREAKING IN THE HUB AREA.

Consequence:

A BROKEN STEERING KNUCKLE COULD RESULT IN LOSS OF STEERING CONTROL AND A POSSIBLE CRASH WITHOUT WARNING.

Remedy:

DORMAN WILL NOTIFY OWNERS AND REPLACE THE DEFECTIVE STEERING KNUCKLES FREE OF CHARGE AND REIMBURSE THE REPAIR FACILITY OR OWNER FOR LABOR. THE RECALL BEGAN ON FEBRUARY 23, 2009. OWNERS MAY CONTACT DORMAN'S TOLL-FREE HOTLINE AT 1-800-523-2492.

Potential Units Affected:

979.

Notes:

DORMAN PRODUCTS, INC.

No wonder why GM has failed. My dad's Buick does the same thing with shifting.

Oh, and check this out. I bought my 97 BMW in 07, found out that there are pixels missing on the on-board screen (problem with most BMW with those screens) and called BMW NA. They covered the part $700 and I just paid 1 hour of labor at the dealership - $100. Mind you, we're talking a 10 year old car and they covered something that WAS NOT all that important.

Talk about customer service. Karma is a *****. GM found it the hard way.

One Buick owner that commented on another forum said that there is some kind of wiring shortage in the door, which runs down the alternator, which causes the transmission to shift hard/whine.

Also, when I took my Buick to the shop a few days ago to get the CV shafts replaced, my mechanic told me that if the battery is bad, then it will cause the computer to have problems. The computer has to keep up with the transmission in order for the transmission to work properly. Perhaps a new battery may fix the problem. Probably not, but just thought I would throw it out there since nobody seems to be able to figure out exactly what is causing the problem. There is no way that I am paying to have any kind of anything replaced in the transmission, when I've read multiple accounts of people paying to have their transmissions rebuilt, just for it just to do the same thing a year later.

GM really needs to do something about this. It's ridiculous.

Hi.

I have two 2000 Buick’s. One does the transmission bucking thing (with the check engine lite on) the other didn't. The one that did the bucking thing (which, I decided not to fix) eventually started misfiring in the engine and I thought I had blown the engine. I took it in for a diagnostic and the repair person found codes P0131, P0300, PO730. He said it needed a new Fuel Filter #23311. After putting on the Fuel Filter he said the car was running almost perfect. He said it could use an Oxygen circuit low voltage-sensor 1, #XTP48309. I told him to replace it. I went to pick up the car, No Bucking, No sluggish transmission, check service lit off, Runs as good as when I bought it 6 years ago. Is this a miracle? Thanks, Jim W.

2001 Century - same issue with trans whining (kind of a generator sound) / hard shifting. Didn't show up until around 100K when I had trans fluid flushed. Thought it might have been some sediment clogging up sensor or something. Sporadic - some days it does it some days not. Doesn't seem to depend on weather. I drive 45-50 miles to work every day and a few 400-550 mile trips a month so fairly high mileage I guess. Car is creeping on 150K and I've decided to live with it until car dies. If trans hasn't blown in 50K miles of this problem probably ain't gonna happen anytime soon. Cheers!

Hi everyone with tranny hard shift problem. It isn't only Buicks with this problem, it's all GM cars with the 4t65e tranny. I have a 2001 Oldsmobile Intrigue and I've got the same problem. It's amazing to see how many people have this problem and GM could care less they knew of this problem when the tranny came out in 97 and didn't address the problem till the 2003 models. They are aware of this, but it would cost them billions to recall this. They did issue a service bulletin, which in my opinion is useless, I am glad GM is sinking fast and I will never purchase another GM car because of this issue. I believe any one with this tranny will experience this problem at some point in time. My Uncle has it too, he has on Olds Aurora. With all the lemon laws and laws to protect consumers out there, you would think they should be forced into recalling this. Anyway here is the service bulletin just look at all the models included. What a joke...

Section: 07 - Transmission/Transaxle

Bulletin No.: 0O-07-30-002B

Date: July, 2002.

Subject:

Slips, Harsh Upshift or Garage Shifts, Launch Shudders, Flares, Erratic Shifts and Intermittent Concerns, DTC P1811 or P0748 Set (Replace Pressure Control Solenoid Valve Assembly)

Models:

1997-1999 Buick Riviera

1997-2002 Buick Park Avenue

1998-2002 Buick LeSabre

1999-2002 Buick Regal

2000-2002 Buick Century

2002 Buick Rendezvous

1997-2001 Chevrolet Lumina

1997-2002 Chevrolet Monte Carlo

1999-2002 Chevrolet Venture

2000-2002 Chevrolet Impala

1997-1999 Oldsmobile Eighty Eight

1997-2002 Oldsmobile Silhouette

1998-2002 Oldsmobile Intrigue

2001-2002 Oldsmobile Aurora (3.5L)

1997-2002 Pontiac Bonneville, Grand Prix

1999-2002 Pontiac Transport/Montana

2001-2002 Pontiac Aztek

with Hydra-Matic 4T65-E (RPOs MN3, MN7, M15, M76)

Condition:

Some owners of the above vehicles with a HydraMatic 4T65-E transaxle may comment on harsh upshifts or harsh garage shifts, soft shifts, shudders on hard acceleration, or shifts erratic. These conditions may appear intermittently or set a DTC P1811 or P0748. During diagnosis, a low or high line pressure (actual versus desired) may be observed.

Cause:

The above condition may be due to any one of the following which may affect line pressure output:

* Sediment inside the pressure control (PC) solenoid valve, causing the PC solenoid valve to mechanically bind.

* Sediment in the valve body, causing the torque signal regulator valve to stick.

* Incorrect transaxle oil level.

Well after reading everybody's comments, I have a pretty good idea whats wrong with my car. No need to say what kind, I'm sure you can guess what model since my comment is at the moment the last.

I would like to say thanks to everybody who commented and provided useful info for everybody in need, even everybody who insisted on doing nothing but repeat the same problem over and over because it lets us know that we are not alone. We all feel the frustration because it is our own.

This company has provided us with a headache where the only cure is sell the vehicle or to never buy one, but as one of the former commenters mentioned, every car make and model has its problems, I just wish mercy on our grand and great grand children.

I have the 2000 Century and have put up with the shifting problem since I bought the car with 36,000 miles, 7 yrs ago. It's been a good running car. I did however change the fluid @ 100,000 miles and did add a thick Slick 50 trans kits to it. It helped a lot, but is still there.

But now I have 165.000 miles, when you accelerate it feels like the brakes are applied, but when you let up on the pedal, it coasts to a stop like nothing is wrong, and all the dash lights are on, and a week later she started to miss. Just replace the fuel filter like I do every year. Anti-lock brake light, service engine, charging.

I know what everybody here would say!! Time to get a new car, but in these times we live in I can't afford 2 or 3 thou down and 450 to 500 a month payment plus full coverage insurance. I'm thinking PCM or ECM, but would like some input.