Why do our trucks shake so bad when we shut them down?

Is that hard on the motor mounts?

How reliable are the motor mounts?

Sorry for the dumb "?"

 

They shake because the high compression brings the crank to a stop rather abruptly once the fuel is cut off. Autos are worse than standards because the mass of the flywheel in the standards absorbs some of the shock while shutting down...essentially slowing down the stopping, if that makes any sense. While I'm sure the 'wet dog shake' is doing the engine mounts no favors, mine are 412,000 miles old and still holding up, so they can't be too weak
greg

 

They're full-circle biscuits around a thru-bolt, as are all late Chrysler insulators - can't hurt them.

I'd be more concerned about the sturdiness of the frame and body, but they seem to last, also.

 

Never heard it refered to like that before.


Rich

 

I got a buddy that has a 3.9 in a half ton chevy. He decided the motor mounts were to soft and replace them with some real hard ones, what a mistake! It is about to shake the bumpers off of the truck and the dash is coming apart. I don't think we realize how much these motors are isolated from the rest of the truck.

 

I asked this same question over in TDR and got a similar answer, but want to add a little more. It seams that the Dual Mass Flywheel adds to the shaking on shutdown as the parts unwind. They suggested engaging the clutch on shutdown, this lessens the shake, and it works.

 

Good advice for 3rd genners, but remember, you're in the 12 valve forum--no crazy dual mass flywheels here