Wanted to try quieting down our fld120, so I put dynamat and liner on floor and back of cab. Still need to do the rest but the floor thumps a lot with a very low pitched loud rumble when the motor is under load between 1400-1 600. Haven't found anything loose or rubbing. What else should I be looking at. Thanks.
I was wondering about the mounts. I'll have to look close at them or just swap them and see. It's old enough, probably needs them anyways. Exhaust is brand new and not contacting cab anywhere nor is any piece mounted to cab
Check the cab mounts and also the cab shocks. We replaced both and it really helped. At one point one of the shocks was rusted and frozen into place and made the truck "tilt" which in turn chewed up one steer tire all the time. Once we got that fixed, the tire issue went away with the noise.
Motor mounts most likely. If you get a lot of thumping when hitting bumps, check those hood cones on the firewall.
Hood is very tight, that was another thought, no extra thumping on bumps really. Cab shocks are new. I'll start with motor mounts. Thanks.
Also look at your bellhouseing,mainly around the mounting bolts. Look for cracks or any shiny metal. Seen dump truck where bolts were over torqued,galled the threads they were holding but not tight.
