1996 GMC K1500 - Replace Dual Catalytic Converter & Y Pipe

[imv8n]

My catalytic converter seems to have gone bad on me. In looking under the truck it seems the dual cats are all one piece including the pipesthat veer off to the exhaust manifold. Im looking to tackle this job myself in my garage. It seems that there is mostly clearance to remove the cats and pipe but there are some areas that look a little tight. I am just wondering if anyone else has done this job before as a home mechanic. What am I in for. Is this doable without raising the truck? I have big tires and about 20 inches of clearance. Any advice or suggestions would be greatly appreciated. Attached is an image of the part that I am replacing. 

[CamGTP]

Very possible that you will have to remove the transmission crossmember and support the transfer case/transmission with a jack so you can lower the exhaust out.

 

Been a while since I've looked under an old truck like that, that sure is a weird looking y-pipe setup. I'm so use to the design where the pipe for each bank has a cat right after the flange at the manifolds and merges at the "Y" with a single connection to the cat-back system.

[alpinecrick]

It would certainly be easier if the truck was a bit higher on jackstands, even a lifted one.  And yes, the down pipe/cats section will come out without having to remove any crossmembers or other big stuff......   

 

If the exhaust has never been off be prepared to replace an exhaust manifold stud or two at the collectors.  Heat and rust make can make it tough to get the nuts off the studs.  Same thing at the flange section where the down pipes and mid pipe are joined with the two flanges.  There are three studs on the down pipe flange and it's not uncommon to break those when removing the nuts.  I drilled mine out and replaced them with 3/8" grade 8 nuts and bolts.  Will need to replace the flange gasket, the old one will be toast.

 

There are three O2 sensors on the down pipe section, so they will have to be unplugged, and once the down pipe assembly is out, the sensors have to come out and installed in the new down pipes.

 

The first time I removed the exhaust from my 96 K1500, it took a while........