Hi guys

Ive notice a knocking noise underneath while drive , I was reading that may be the mounts for the exhaust are broken or a problem with the shaft .
It is intermittent , most common while passing around the 45-50 mpg range

I will check the exhaust
Please any advise how to check if there is a issue with the shaft before taking it to the dealer

Any other thing to check ?

Thank you all

 

Crawl underneath with a rubber mallet and tap on a few things to see if anything seems loose or rattles. That would be my first guess. I would certainly check that before spending money at the dealership. But I refuse to go to the dealership in general...

The down tubes, or collector pipes from the exhaust manifold could be broken or loose which could cause the exhaust pipe directly under the area of the driver seat to come into contact with the second back latter looking skid plate under the truck. Might check the clearance between that pipe and the steel bar of the skid plate.

If it was the front drive shaft I would think you would have much more noticeable symptoms and much bigger problems. While you are under the truck make sure the universal joints all look good on the drive shaft.

Hope that helps, let us know what it turns out to be.

Ross

 

I agree with Ross