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Buick Century Transmission Shifts Hard

Just purchased a 2000 Buick Century and am enjoying it, except the transmission shifts hard between gears a lot of the time. Doesn’t seem to be a pattern, but hard to tell. It shifts smoothly for a while, then doesn’t. Any ideas? Is this damaging the transmission?

Start by checking the transmission fluid (if you haven’t - you didn’t say). Make sure it is at the proper level, and note the color and smell. It should be a nice clean red color - maybe a little bit brownish, but not too much and shouldn’t smell burned at all. If it is low, add and have a good local trans shop evaluate it for leaks. If it looks brown to black and/or smells bad have a good local trans shop service it right away. (I would have it serviced anyway - pan drop and filter change - unless you know for certain that it is up to date in that regard).

Thanks for the quick reply! Actually, we did have it checked…sorry for not mentioning it. The mechanic said the fluid level was too high, so removed some. He said everything else looked just fine. Thought that would remedy it, but even though it is better, it still shifts hard a lot of the time. My husband checked it a few days ago, according to the user manual, and it was still 1/8" above the indicator on the dipstick. Is that significant?

I will only add a couple of things to cirgroller’s comments. If it smells and looks bad, you may be in for a hefty repair. You always can try cleaning the filter and replacing the fluid. Sometimes you just get lucky, but often the damage is already done. Many people like to blame the fluid change as the cause of the final failure, when in reality the change was due to the problem.

Good Luck

The little bit of overfill that you might have left won’t cause hard shifting. I also wouldn’t lose any sleep over that part. Did the mechanic say anything about the condition of the fluid?

The hard shifting is not terrible for the transmission. Slipping (when the engine revs but doesn’t produce more power to the wheels) is bad, but a transmission can live with hard shifting for a long time.

I think you have two options if you want to address the issue. One is to find a good local transmission shop - no big chains (e.g. AAMCO) - find a local place that folks know and trust. Ask them to look it over, drive it, and run diagnostics. If that turns up any malfunction codes, post them up here - there is something of a resident transmission expert who comes through regularly.

Second, skip the diagnostics, and just have someone drop the pan, check it for debris, and change the filter. Do that twice within the next 10K or so. Sometimes things like hard shifting can just come from accumulated gunk in the fluid passages and solenoids over time. Getting in and keeping in fresh, clean transmission fluid can help.

And make note of Mr. Meehan’s comments below. I can only hope that if your fluid was burned up that your mechanic would have said something about it.

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Hey guys, Husband here…Thanks for ALL the great replies. I have more information concerning this problem.
The car was recently purchased by us from a 95 year old lady who’s children convinced her to quit driving.
The vehicle is a 2000 Buick Century, 38,400 miles that wasn’t used much at all…very clean…almost like new.
I took it to my garage to have it and the hard shifting checked out. It shifts smooth for about the first 30 miles then it starts to shift hard.
I was told there were “no codes”…“trans oil nice and pink, not burnt”…“too much fluid” so they drained some out but it still shows 1/8" above the sticks acceptable full area.
Have been driving it a lot, trying to work-out the hard shift…after 400 miles of driving it still shifts hard after 30 miles or so.
I am planning on having the trans fluid and filter changed before we start throwing parts in it.
Thanks again for all of your help.

Very late reply I know, but did the problem turn out to be a pressure control solenoid?

@cdaquila Now not only is an old thread revived but right above the revival is old spam.

@Tinker1000 It would be best to start your own thread with a good description of your problem and you could have a better chance of response.

Back to 2000 Buick Centurys:
My wife’s Buick with 149K miles is on its second tranny. First one was rebuilt at 108K because of whining and slamming into gear after “driving ~40 miles”. It didn’t behave normally until it cooled off for several hours.
Now at 149K it’s deja vous all over again. Same symptoms. I have it serviced at recommended intervals. Fluid is checked and is red and sweet smelling. Is the only cure a different car? My wife won’t give it up until the tranny self-destructs. I’m concerned mainly because of the time and place where that occurs. Al

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