99 C2500 7.4l front cat laying on crossmember

[Jrw261]

My 99 C2500 with a 7.4 has gradually started rattling. I assumed it was my cats coming apart but while going through the front end this weekend I noticed the front cat is laying on the heat shield and cross member. I slide back there to lift it up and it didn't budge.

Ill spend more time investigating tomorrow but I didn't see a faulty hangers and most of that hangs from the manifold anyway. Engine mounts look good too.

Has anyone had experience with this before?

 

[5vortec7]

I started getting a loud rattling last night. At first I feared it was coming from bottom end of 7.4 or the tranny but I think I narrowed it down to the cats as well. Didn’t notice it laying on crossmember but it was dark in a gas station. Did you find the cats were shot or?

 

[arrg]

If nothing is loose with your exhaust, the problem is likely your transmission mount and/or your engine mounts. The rubber breaks down over time and your whole drivetrain sags. I had the same problem with my converter, so I replaced my transmission mount and gained almost 1/2" of clearance.

 

[Elroy]

i replaced my stock exhaust with the magnaflow stainless , both cats , everything from the stock manifolds back, not cheap but it was necessary and worth it, i probably need to replace the mounts too

 

[Supercharged111]

My dually had that. Whoever replaced the muffler back before me used a tailpipe with 3/8" hangers that tore through the rubbers. Hanger height was also incorrect on that system.