Automotive Vibration Troubleshooting - The Three Types of Driveline Vibration

There are several different possible causes for a driveline vibration. Your wheels, tires, axles, driveshaft, transmission, clutch or torque converter and engine components are all rotating at a high rate of speed, and any one or more of these components can create a vibration if they are worn or out of spec. Worn or broken engine or transmission mounts can transmit normal vibrations that usually aren't ever felt, and accidental body contact with the engine, transmission, or exhaust can also be misinterpreted as a driveline vibration. The first step in diagnosing a classic car vibration is to determine exactly when and under what conditions the vibration occurs.

 There are three basic types of vibrations:


 1. Engine RPM related - If the vibration is related to engine RPM, it will occur in all gears (and possibly even sitting still) at a particular engine RPM or above. This vibration usually can be attributed to the engine itself or anything else that turns at the same speed as the engine, such as the harmonic balancer, flywheel or flexplate, pilot bearing, pressure plate, torque converter, or transmission input shaft. It is also possible for body contact with the engine, transmission, or exhaust to cause an engine RPM related vibration. Worn or broken engine or transmission mounts can contribute to this problem. When driving the vehicle with the vibration present, maintain vehicle speed and try shifting to a lower or higher gear. If the vibration changes or goes away while maintaining the same vehicle speed, then the problem is not related to engine RPM.

 2. Vehicle Speed related - If the vibration is related to vehicle speed, it will not be present until you reach a certain speed, and then it will usually start gradually and then become worse as speed increases. In some cases, it will decrease at some point, and then come back again at a higher speed. This type of vibration could be related to your wheels, tires, axles, differential, driveshaft runout, balance, or angles, universal joints, or transmission output shaft. Try the same driving test as above. If the vibration is present in third gear at 50 mph, but shifting to fourth gear at 50 MPH makes the vibration go away, then it is not going to be vehicle speed related and you can usually rule out any rotating component that is further back than the transmission output shaft. At a given MPH, your output shaft, driveshaft, axles, wheels and tires are all turning at a constant speed, no matter what gear the transmission is in.

 3. Accel/Decel/Cruise related - A vibration that changes depending on whether you are accelerating, decelerating, or cruising at a steady speed could have quite a few different causes. Generally, this will be related to driveshaft angles or a worn or broken part, instead of something being out of balance. Think about what changes when the engine is under load. The engine and isolator mount loads shift; the load on the pinion bearing changes; your driveshaft angles change, possibly more than they should due to a broken engine or transmission mount; your exhaust, shifter, transmission, etc. could be contacting the body only on accel or decel; if the car has been lowered (or raised), your suspension snubbers could be contacting the body prematurely.

 A vehicle works as a system, and you have to understand the relationships between all the different parts when you are trying to diagnose a driveline vibration. Determining if the vibration is related to engine speed, vehicle speed, or engine load will help you narrow down the list of possible culprits, and keep you from wasting your time looking in the wrong places.

Auto Insurance in Iowa

The state of Iowa does not require that all drivers have a liability auto insurance policy. Unlike most other states, Iowa does not have a compulsory insurance law for drivers. However, the law requires that the driver as well as the owner of the vehicle, be able to show financial responsibility.

 Iowa is not a -no-fault- state where a determination as who caused the accident, is discovered and settled through the Tort legal process. In other words, if there is an accident, one of the drivers will be identified as the cause or at-fault in the accident. And being at fault must pay damages. In most cases, the auto insurance company of the person at fault will pay the damages. Because Iowa is a Tort state, most insurance companies recommend that driver's consider carrying higher coverage than just the state minimums.

 In the state of Iowa, all motorists must show proof of financial responsibility to peace officers upon request. The most common way is to purchase a valid liability insurance policy. Once the policy is issued, your insurance company will send you an insurance card, which you will keep in the car, at all times.

 Iowa's Financial & Safety Responsibility Act provides that drivers who drive dangerously, as well as not being able to prove financially responsibility, can lose their driving and registration privileges terminated. Once that occurs, they will have to prove their ability to pay for any destruction of property or injuries caused.

 In circumstances where the driver or owner does not have auto insurance, they can contact the Office of Driver Services at (800) 532-1121 for submission instructions, to learn of the alternate forms of proof of financial responsibility that can be used.

 The state of Iowa has established the rules and guidelines, for allowing car insurance companies to use the personal credit history of the driver, to assist in determination of rates and products to offer. The rates are calculated based on factors including the age of the driver, the car type, driving record, location of residence, as well as the marital status. And those drivers with accidents and tickets on their driving records pay more than those with good records.

 In Iowa, the minimum liability coverage required, is bodily injury coverage of $20,000 per person, up to $40,000 bodily injury coverage for all persons per accident, and for property damage coverage caused in an at-fault accident, $15,000.

 Auto insurance companies operating in Iowa must offer uninsured and underinsured motorist coverage, where the driver has the option to buy it. Iowa insurance providers also offer collision coverage, comprehensive coverage. Because Iowa is a Tort state, consumers would be advised to buy additional coverage.

 In Iowa, there are rules regarding whether a driver has prior insurance. If your insurance lapses and you are operating a car, technically you are driving without insurance. If you are found to be driving without insurance, you will receive a citation and be fined. If an accident occurs, you will be fined and your license may be revoked, possibly for one year.