Shuddering between 40 and 50 mph 2000 Buick LeSabre

[NickaV]

Hello all,

My Buick shakes/shudders whenever I am accelerating between 40 and 50 mph, it stops when I take my foot off of the accelerator but as soon as I put my foot back on it starts up again. It also gets worse when there is more weight in the car.

Unsure if this is a transmission issue or tire issue. I just got new tires about 4 months ago and they are due for a rotation, not sure how much of a factor that would play.

 

[DonP]

I would be a bit surprised if it a tire. Did it just start recently, or back when you changed the tires?

Any other smptoms at other speeds, on hills, decelerating, turning, etc?

Any tendency to stalling?

Does system temperature (warmed up vs. still cold engine/tranny) have any effect?

Any hidden/pending OBDII codes?

 

[NickaV]

I would be a bit surprised if it a tire. Did it just start recently, or back when you changed the tires?

Any other smptoms at other speeds, on hills, decelerating, turning, etc?

Any tendency to stalling?

Does system temperature (warmed up vs. still cold engine/tranny) have any effect?

Any hidden/pending OBDII codes?

Started about two months ago, but transmission has been acting up a bit since early summer.

No stalling, and no other symptoms. I did notice while driving around today that it is barely noticeable while the engine is cold, but as soon as the engine warms up it gets worse. It is worse going up hills.

Also no OBD codes.

 

[DonP]

Is it harsh shifting on the 4-3 downshift?

 

[NickaV]

No harsh shifting down, it does shift up hard though. The problem has evolved and now shakes in all of 3rd gear and gets worse until it shifts into 4th. As soon as it shifts into 4th the problem disappears.

 

[zaxbat]

Speed related shaking or shuddering is often related to tires, but your problems are not directly related to speed. Need to get your transmission checked out. With a lot of luck, it may need a simple adjustment. However, anything more than that can often cost as much as a new transmission would (and that is often more than the value of the car). I hate transmission shops. Good luck.

 

[NickaV]

Sorry to bump this old thread, just wanted to update that it was just the CV axles. Both inner and outer were bad. replaced both of them and the problem disappeared!

 

[markolinux]

Thanks for reporting back, NickaV. I'm having similar issues with my '02, and now I have some things to check out.

Mine is shaking between 45 and 55, and only when accelerating. The harder I accelerate, the worse it is. (Going up hills, etc)

I also had the transmission replaced about 20,000 miles ago, and my cousin (who has owned a garage for the past 25 years) says it might be the torque converter. He ruled out tires as the issue.

Is there a way to check the CV axles other than just replacing them? Probably not, I'm guessing...

 

[NickaV]

If the shaking only appears when you are accelerating and only in that speed range, that's a pretty good indication that it might be the CV axles. The only ways (that I know of) for checking the CV axles when they are on the car is to see whether the rubber boots are torn and leaking grease. CV axles generally only fail when the boots tear because all of the grease leaks out leading to friction etc, though it is possible for them to fail without the boots being torn.

You can also get under your car and grab the axle and try to move it with your hands, if there is any significant movement it is 99% sure a bad axle.

 

[gnhbodyguy]

Whenever I hear shuddering on acceleration and hills I think spark plug wires. A common problem. The conductor wears out with age.
https://www.youtube.com/watch?v=4_EFGAFxi1w

 

[NickaV]

Whenever I hear shuddering on acceleration and hills I think spark plug wires. A common problem. The conductor wears out with age.
https://www.youtube.com/watch?v=4_EFGAFxi1w

I would think if it were spark plug wires the issue would be apparent every time you accelerate, when it's just apparent in the 45-55mph range that makes me think it is something else

 

[HotZ28]

I would think if it were spark plug wires the issue would be apparent every time you accelerate, when it's just apparent in the 45-55mph range that makes me think it is something else

That is exactly the speed where misfire takes place, especially under a load, such as going up an incline.

 

[NickaV]

That is exactly the speed where misfire takes place, especially under a load, such as going up an incline.

It makes sense that it would be worse under a load, but wouldn't a misfire be apparent at all speeds as well as idle?

 

[HotZ28]

It makes sense that it would be worse under a load, but wouldn't a misfire be apparent at all speeds as well as idle?

Not necessarily. I have seen many misfires caused by bad wire(s) that would not cause a misfire until the engine is at normal operating temp and placed under load. You can consider load to be the case in 3rd or 4th gear @ 40-50 mph especially on an incline.

 

[NickaV]

Not necessarily. I have seen many misfires caused by bad wire(s) that would not cause a misfire until the engine is at normal operating temp and placed under load. You can consider load to be the case in 3rd or 4th gear @ 40-50 mph especially on an incline.

Hmm, good to know! Thanks!

 

[turblown]

My 2000 had the same problem, cv axles fixed it

Sorry to bump this old thread, just wanted to update that it was just the CV axles. Both inner and outer were bad. replaced both of them and the problem disappeared!

bumping this up because I fixed the problem. It was indeed the driver's side half-shaft.

Moral of the story is, use oem replacement half shafts 😱

I'd put my money on a CV joint about to crap it's pants.

+1 for cv axle replacement! 2002 Buick Regal GS Supercharged.

At first I had vibration under acceleration at any speed. I checked the lower motor mounts and they were both blown / leaking, so I replaced them. I also performed the motor mount rotation mod on the two dog bone mounts on the front of the engine. Test drove the vehicle and it drove fine with no vibrations... until the next time I had a passenger in the car. The car started shaking violently when going from 40 to 50 mph, even under slow steady acceleration. Doing a bit of research I found that the recommended fix was to replace the cv axles. I checked the OUTER cv joints by driving slowly in circles in each direction at full steering wheel rotation. There was no clicking noise, so I knew they were okay. I got under the vehicle and checked all the boots. All of them were in perfect condition with no apparent rips or leaks. I even moved the cv axles around by hand to see if there was excessive play, but there was nothing out of the norm. So, I replaced both cv axles based on the recommended fix, assuming that both INNER cv joints were bad and it worked! Acceleration is now extremely smooth with or without a passenger. Thanks for the info!

 

[Ronnyg1234]

Not necessarily. I have seen many misfires caused by bad wire(s) that would not cause a misfire until the engine is at normal operating temp and placed under load. You can consider load to be the case in 3rd or 4th gear @ 40-50 mph especially on an incline.

Only problem is that if it was missfiring you would get a missfire code! Remember that there were no codes showing. A bad cv axle would not show a code. Most find that the problem solved would be either bad cv axle or a bad tire.

 

[BuickGirlFromMars]

a torque converter clutch could also cause engagement of gear shuddering but likely wouldnt be constant unless it was that badly worn that it cant lock the coverter and it slips under low load but then you prob have other issues with your trans lol

engine mounts can do a sim thing, but usually higher speed or just under load