DriveLine 101

A driveline is the heart of a vehicle — from the engine to where the wheels bolt on. In this section we share some of our 195 years of combined experience, straight from the shop floor.

What is that vibration?

Posted by Tom in DriveLine 101

"HOLY CRAP" — where do we start? Well, get ready...

• 1st — Determine if the vibration started all of a sudden, or has it come on gradually?
• 2nd — Determine if the vibration is "wheel speed" or faster. Is it a wobble, shake, buzz, etc.?
• 3rd — Is the vibration in the steering wheel or in the "seat"?
• 4th — Probably most important: is it intermittent, or constant?

Sudden vibrations

Sudden vibrations can be caused by many things. For example: a tire that is separating, or a bulge in a tire, is a very common "sudden" vibration. Sometimes when you purchase new tires the balance may be a problem — an out-of-round tire can "spin" in the balancer correctly but won't "roll" worth a darn. Another possibility: rubber-necking at the opposite sex, leaving the road and hitting a curb will bend a rim or axle, causing damage you might not be able to see, but are able to feel. Showing off how bad your 4x4 is to your buddies can cause immediate problems — drivelines are not "ROCK" proof. Engine problems can also cause sudden vibrations: a bad fan clutch, water pump, or an engine miss are possibilities. Other catastrophic failures, such as transmission or differential issues, usually don't cause vibrations — but anything is possible.

Gradual vibrations

Gradual vibrations are harder to diagnose. As with sudden vibrations, the causes can be drivetrain, tire, engine, or something entirely bizarre. Tire problems, worn U-joints, or carrier bearings are probably the most common. Everyone thinks if a U-joint is "tight" it is still good. U-joint wear goes like this: a U-joint will rust solid before it gets loose. Once it gets to the loose stage, it's not long for this world. If you let a U-joint get so bad that it falls out, it can not only cause catastrophic damage — it can be very dangerous to everyone involved.

Sometimes vibrations come on so slowly you get used to them, until it's too late. Lots of times customers wait too long to repair a U-joint issue, and it changes their repair bill from a $20 U-joint to a $2,000 transmission.

Other common drivetrain vibrations are caused by ANGLE issues — but that will be covered another day. My brain is mush!!!

If you have a problem, or need help setting driveshaft angles, give us a call or bring it in — we're here to help. Get all your ducks in a row: the more you can tell us, the better chance we have to find and fix the problem. DON'T WAIT! The sooner the problem is fixed, the less likely there will be other related issues.

Thanks for listening,
TOM