How to tell if your shocks are bad

Doesn't always work that way. The best way is ...

if the shocks are on the truck for over 125k ...

Replace them.

Sometimes it is better to replace them at 90k.

 

On the road I drive on, I bet 50 gets them in the summer months, in winter the roads are much smoother, but shocks don't work well at 40 below either.

 

I have bought a used Freightliner truck from second owner with over 1 million miles with original shocks. All of my 3 year old trucks that i bought from dealers with 400k to 600k miles have original shocks. The current truck that I just bought, 2016 Kenworth T680 with 390k miles have all original shocks. I know they are original shocks because the bolts still have original paint.

I have been told by dealers to change shocks every year or 100k miles. But no one is changing them. So far, everytime I change shocks, I have not notice much improvements in vibration or roughness. Even when I have bad tire wear or rough bumps, changing shocks did not resolve my issues. This is probably most people do not change shocks if they still look good.

 

Think I've read before that the shocks are the most overlooked maintenance item on a truck, or atleast one of the top overlooked...

 

I replace shocks every year but I also don’t notice any difference at all.

 

I usually replace shocks when they are start leaking... if it’s not yellow ones, those filled with some gas and you can tell by how warm are they. Lot of people saying to replace them every time you change tires. There no point to replace every 100K miles.

 

Curious as to why you would say that; was told by more than one very qualified tech that checking the temps is an excellent way to diagnose working / non working shocks. Also an easy way for a driver to check while doing a mid trip walk around. No argument about the replacement interval, if that’s your thing. Place the shocks of a passenger car next to the shocks of an eighteen wheeler, look at their physical size, then take note of the the amount of weight difference of the respective vehicles, I find it hard to believe that an eighteen wheeler shock really serves a purpose. My 2007 T800 has over 1 million miles, & only 3 shock replacements iirc. I run Michelin tires & closely monitor tread wear patterns, generally trying to do a 3 axle alignment after drive tires are replaced. I am a firm believer that is a critical maintenance item with even tread wear as the reward. Talking out the other side of my mouth, I feel that a working shock is useful on any vehicle, but again, for the weights we deal with shocks would need to be considerably larger. One other thing just popped into my mind, (pun intended) when I recently went to the dealer to replace my splitting sleeper cab air bags, I was corrected on the air bag term, told that it was actually called an air shock.
Just my $.02

 

Another way to tell if shocks are bad is if you get bounced out of the seat. I complained about the ride of my old cab to the shop, and the shocks had been on so long that they had to cut them off. They were frozen solid.