2000 LeSabre front end shakes when accelerating in a right turn

[mike082679]

Hello all. I have a 2000 LeSabre Limited that has developed a bad shake in the front end that is felt mostly when accelerating around a slight right hand curve, the harder the acceleration the worse the shaking gets. Local shop looked at it and told me it was the front tranny mount. The mount was definitely broken, however after I installed the new mount the shake is still just as bad. Took it back to the shop and after another review they thought my new mount was broken as well, so I returned my 1st new mount and replaced with a 2nd new mount and still no luck. Any ideas what may be causing this issue?

[maxwedge]

Without onsite inspection and a road test, very difficult. I would think this could be a bad ft axle.

[TTCzar]

Hello:

May want to check out your front stabilizer bar end links. The rubber can wear out or they rust and break. This not only causes shake during turns but a distinctive metal on metal bump sound. Worth a look.

Good luck.
TC

[mike082679]

Okay, I checked the stabilizer bar end links, nothing seems to be unusual or wore out there, looks solid and cant feel any movement. I was leaning more towards a CV axle being bad but I am not sure how to check them, other than inspecting the grease boots for leaks. Is there a way to check the CV joint while still in the car? I've seen similar symptoms as this on another car when the dogbone torque strap went bad, but if this car has one I haven't been able to locate it yet. I just got back from strapping a digital camera and a flashlight up under the hood and taking video at different angles of what's going on while I'm driving, unfortunately the shaking is so bad when the problem occurs that the video becomes a motion blur.:o) It was worth a try anyhow, haha.

[HotZ28]

Have you tried the engine torque test, to see how much movement you have in the engine/transaxle? This test will also help you see if you have other mounts that are broken. It is best to have an assistant available to look under the hood and at the mounts while you start the engine, put the car in drive (with brake applied) and bring engine rpm up to 1500 rpm. Watch for abnormal movement, or lifting. Have you checked the front hub bearings & had the tires inspected? Where do you feel the shaking coming from, drivers side, passenger side, or both? Do you feel it through the steering wheel, or does the front body shake? Any noise associated with the shaking?

[mike082679]

We ran the engine torque test at the shop, resulting in diagnosing the front transmission mount as the problem. After replacement didn't correct the issue, the shop re-ran the same test (while I watched) and observed all other mounts, none of which seemed to be out of order. The bearings don't seem to have any play at all, neither do the ball joints, stabilizer bar ends or tie rod ends. When the event happens, the entire front end of the car can be felt to wobble side to side, seemingly on both sides. It can be felt slightly through the steering wheel but more so in the entire front of the car, and even pulsing through the gas pedal. The wobbling is accompanied by a "thud, thud, thud" noise that gets louder the harder the acceleration. As soon as the gas pedal is released the event will end and car rides like new.

[C man]

A coworker of mine is having the exact same problem. When I drove the Grand Prix it had the same symptoms you described. the whole car shakes under acceleration and the faster you go the harder it shakes. and it pulls heavily to the left as soon as you let the steering wheel go. I'm leaning toward a bad halfshaft. So your not the only one having this problem.

[mike082679]

I just discovered another symptom. With the car sitting in the driveway running in park, if I turn the steering wheel slightly side to side there is a popping sound that seems to be coming, as far as I can tell, from the strut tower on the drivers side. At any rate when I put my hands on the various components down there the tower seems to be the component most transmitting the vibration. With every "pop" you can see the tire slightly shudder. Not sure if this is related but it's definitely something.

[HotZ28]

With the most recent revelations, it sounds like the upper strut bearings are binding, consequently the "popping" sound when turning. Have you notice when making a sharp turn if the wheel/tires seem to continue turning rather than correcting to the straight ahead position?

[mike082679]

Update: problem is solved! The inboard plunge joint on the passenger side CV shaft was bad. The joint was knocking and causing the entire front end to shake. I pulled and replaced the entire passenger driveshaft and now the car drives like new! Best of all, it only took about 1.5 hours in my garage and the driveshaft was only about 70 bucks at o'reilley's. The side to side popping sound in the driveway is still slightly audible, I have a feeling that the driveshaft wobbling so bad has sped up the wear on my strut bushings, but it's not bad at all and doesn't affect handling in any way. I'm a very, very happy camper. Thanks to all who helped, front end problems can be so tricky to diagnose!

[maxwedge]

Thought so, common issue and tough to pinpoint. The joint will lock up at certain times and this transmits to actually moving the drivetrain side to side.