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Ask GM Tech (Cam) Your Own Question
GM Tech (Cam)
GM Tech (Cam), Chevy Technician
Category: Chevy
Satisfied Customers: 15133
Experience:  GM Grand Master Technician 2007. 14 years experience.
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Bad vibration between 40 to 60 mph. if you let off the

Customer Question

bad vibration between 40 to 60 mph. if you let off the accelerator the vibration stops. only does it on acceleration. 2006 HHR 2.2
JA: How old is the transmission? Have you checked the fuel filters?
Customer: 260,000 miles and nothing done to anything
JA: Are you hoping to fix this yourself? What have you tried so far?
Customer: I have a son that is a auto tech and he doent know. FYI. I did just put new tires and struts on front and it started after that. I have rotated tires with no luck.
JA: Anything else you think the mechanic should know?
Customer: I have had the car off the ground in front and with speed up to 80 mph and no vibration
Submitted: 2 months ago.
Category: Chevy
Expert:  Jared D replied 2 months ago.


Typically a vibration that only occurs when you accelerate is due to a bent or failing axle shaft.

Are you getting any kind of noise from the front end- especially when cornering?

Customer: replied 2 months ago.
No not any noise at all. the car is very smooth riding and driving from 0-100mph other that 40 to 60 mph on acceleration
Expert:  Jared D replied 2 months ago.

Well, I would probably take a look at the CV axles and make sure there aren't any signs of a failing axle shaft (grease on the boots, torn boots, or shiny metal that has been rubbing or binding). You could also make sure the axle joints aren't loose by prying against them with a pry bar to see if they move around a lot.

It's safe to assume the tires have been balanced? Check for signs on the rims that a wheel balance weight might have fallen off.

Customer: replied 2 months ago.
If it was an unbalanced tire it would still vibrate once you let off the accelerator. Also I have jacked the front tires off the ground on front and rear and ran speeds up to 80 mph on all 4 tires with no vibration. you would assume if it was CV joint or bent axle that it would vibrate during the test with the tires being ran while off the ground
Expert:  Jared D replied 2 months ago.

Right, a wheel balance issue shouldn't go away when you let off, but sometimes the vibration isn't as prevalent because the vehicle inadvertently drops speed. Some driver's perception of a vibration isn't as precise as other's.

A vibration from a bad axle shaft shouldn't be as noticeable when the vehicle is off the ground, especially if it was lifted from the frame. When the vehicle is lifted off of the front suspension it will pull down on the axle shaft, often enough to hold it steady and dampen the vibration. If you lifted the vehicle from the control arms, thereby keeping the suspension loaded and the axle shaft in the normal driving position then you would likely still feel the vibration if it is in fact an axle shaft issue.

Customer: replied 2 months ago.
I will try that when I get home today and see if there is any change.
Expert:  Jared D replied 2 months ago.

Let me know how it goes.

Customer: replied 2 months ago.
Jacked car up last night and set jack stands under control arms as if it were level like driving down the road. There was no vibration at all.
Expert:  Jared D replied 2 months ago.

Were you able to feel any play in the axle shaft's u joints?

Customer: replied 2 months ago.
No play anywhere that I could find.
Expert:  Jared D replied 2 months ago.

If you aren't getting any vibrations with the car lifted off of the wheels then the only explanation should be a problem with the wheels or tires. I know that doesn't make sense since it only happens on acceleration. I suppose it's still possible that the problem is in the axles and you don't feel it when the car is lifted because there is no rotational load on the axle shafts, but that is going to be hard to determine. When the wheels were spinning in the air could you see any wobble or variation in the wheels or tires?

Customer: replied 2 months ago.
None at all. I have just rotated tires to see if there was any change and the vibration is consistent don't matter where the tires are placed on the car.
Expert:  Jared D replied 2 months ago.

I'm still suspicious of the axle shafts. It sounds like you have thoroughly checked the wheels and tires. The only thing left to vibrate would be those axles.