Transmission bumps from 1st-2nd-3rd

07 Buick Lucerne V6. This is my second car. From 1st to 2nd and 2nd to 3rd there is a small bump. I can feel it shift in other words. Almost like I get hit from behind but wayyy more subtle, barely noticeable unless your the driver. It does it under light and heavy acceleration and hot or cold. Im used to newer cars that you can’t even feel shift. I’m not sure if it’s normal or not.

Fluid level and condition are fine. No lights on. 127000 miles.

My question is, could this be normal? If not wouldn’t the check engine light come on?

Transmission problems don’t always trigger the CEL. How long have had it? Has it always done this? I might have the fluid changed, making sure the correct fluid was used.


I’ve had it for about 3 months for 2000 miles. Has always done it. Bought it from a single owner older guy who gave me a book of records. Last record for change shows correct fluid but I know they still could have messed up.

I’m dead broke right now so I have to drive it for a few more months until I get finances in order.

Out of curiosity, could this be normal or should all gear changes be smooth as a whistle?

Completely normal. Especially for a 14 year old car with 127K miles.

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Awesome I was hoping to hear that. Just scares me because my last car was a lemon and I know transmission problems are costly.

a lot of newer cars, maybe what you drove in the past have CVT transmissions. just like turning up a lights dimmer switch in the house. you wont feel the shift points. not like older cars. its probably normal. have your dad or older uncle drive it. they will be able to tell you if its normal

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I will when I get a chance! Just for future reference, what does a “hard shift” feel like?

hard to explain but normally a shift point would be just enough to know it shifted.


What you are experiencing sounds normal behavior for an automatic transmission w/over 100K miles on it. My 48 year old truck’s C4 transmission did that when it was new, and still does it, but that’s yester-years technology. Newer designs are smoother shifting.

The reason it happens is b/c it takes a lot of force from the transmission’s hydraulic system to shift the planetary gears into position for the shift. The hydraulic system consists of a pump, a bunch of tubes, and various valves (some mechanical, some electric solenoid) and associated actuators. Those all use seals, and the seals begin to leak a little with time and use. New transmission fluid of the proper spec fluid contains seal conditioning chemicals designed to keep the seals pliable and that makes them seal better. Have you ever seen an oil filter wrench, the type with the metal band that wraps around the filter? There’s something that looks like that inside your transmission too. The band is tightened around a drum (a sort of cylinder) by hydraulic force, and this causes the shift. Over time the band and drum surfaces can wear a little, which results in play between the band and the drum. Some transmissions — such as the Ford C4 – can be fairly easily adjusted to reduce the play in some of the bands. The 2nd gear band adjustment on the C4 just requires tightening a bolt as I recall. Not sure if something like that is possible w/your though. There are clutches inside the transmission involved with shifting too, but those usually aren’t adjustable. They have to be replaced when they wear out.

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Awesome thanks for the explanation! At first I thought it was an issue because to me it seemed a bit harsher than a normal shift point but from the responses it seems I can expect that with an older car.
I found a video where a guy shows a hard shift and it almost bounced his head off the steering wheel lol. Mine moves my head about an inch. To say the least I’m relieved!

If you ever get a chance to drive a sixties era muscle car with an automatic in good condition, not only will you feel the shift points, it is possible to spin the tires when it shifts.


The v6 has the 4t65-e trans which is very common. It might need a simple service. Drop pan, new filter. New fluid. I have never had a trans flush and I don’t think they are highly recommended. Hopefully we won’t spend days talking about flushes.


I plan on that within the next two months to be sure. Thanks.