QuestionI know this isn't exactly your epertise, but I think this may be a drive train problem....so here goes...
My father had a 2001 Jimmy with a shake that developed within the first 130-140 miles of the vehicle's life. This was not resolved, and the front-end was inspected, tightened, and retightened. No problems were found. The vibration happened around 55-65 and shook the whole vehicle. They attributed this vibration to a normal "frequency-related" vibration described as being similar to how a wine glass shatters at a given frequency. This car was traded in after the lease.
I personally own a 2000 GMC Jimmy Diamond and was in a front-end collision whereby a lady backed into me going appx 15-20 mph. I was in reverse, but completely stopped when she hit me (was waiting for traffic to clear for 45-60 seconds - so I was not moving). My car was pointed to an angle of about 11 o'clock with the wheels COMPLETELY turned to the left as if i were parallel parking, and she was traveling straight at 12 o'clock. The whole back end of her Grand Prix hit the whole front end of my SUV. She hit me hard enough to dislodge both front headlights (thou never touching them directly), and pushed the factory Grill Guard so hard into the bumper that it recessed the bumper 1" (Grill guard and bumper are mounted on two different parts of the frame). I've had all 4 tires replaced (she broke the belt(s) on the front left and rear right tires because of the counter-clockwise torque applied to the vehicle), and had to also replace the front left wheel bearing as a result of the accident.
The problem is that before the accident there was no vibration, but now there is an identical vibration at 55-65 that my father experienced in his Jimmy. The dealer says that both axels are fine, and that the rear break drums have been rebalanced. They even put 4 new tires/rims on it from a non-vibrating jimmy and the vibration still persists. It only occurs betweeen 55 and 68, and seems to resolve above 68. Also, sometimes it goes away if i get into the left lane of the highway (i'm thinking because of the pitch of the road?). I feel the vibration in the entire vehicle, and I have not noticed the steering wheel vibrating back and forth (thou I can feel it in the steering wheel, but I guess this indicates it is something in the back maybe?) From my understanding, if this was a front-end problem the steering wheel would be noticably shaking. The SUV has been in the shop over 3 weeks now and nobody can figure out where the shake is coming from. My father and I think it may be related to the drive train seeing as i was in reverse, and I heard they were goign to check the Pinion Angle and the Engine/Transmission mounts. Is there anything in specific I can tell them to look for? Is there anything in the transmission that would cause an entire vehicle to shake like this?
Any help in pointing the dealer in the right direction would be INCREDIBLY helpful!!
AnswerHello Dan,
First...the frequency vibration stuff is a bunch of hogwash, used to describe a problem they just don't know how to find.
If it were normal, every Jimmy would do it, and people would not buy them.
Has anyone raised the vehicle and operated it at the same RPM's on the rack, while watching underneath?
A missing flywheel weight could cause that.
Has anyone raised the engine rpm to about the same while sitting still, and looked at the fan belt driven accessories?
Then there are the front rotors. Hard to spin them that fast while sitting still. They have weights also, and they can be loose. Replacing the rotors would be easy & cheap.
And I am curious about that "Balancing" the rear brake drums. I would just replace them if there was a question about their balance.
And a four wheel alignment would be a good idea. A bent rear axle tube is possible if it hit that hard.
Another thought is a bent driveshaft, which can be seen on the rack.
A trip down the road, with someone in another vehicle following, and watching can sometimes see something. Especially if the vehicle passengers are in communication.
Van
