After searching here and elsewhere a couple weeks ago, I preemptively ordered a cap converter (20822-3Y110) and accompanying mesh insert (20840-3Y110) online. I hadn't yet removed my front precat at the time, and I'm now realizing the part numbers I ordered are for the 3.0L, although the only one courtesyparts lists for A33B states it is for 2000-2003. I guess that's where I got confused, but is there an upper gasket for the 5.5 gen where the precat bolts to the exhaust manifold? Unless it fell off or I just missed it, I don't remember seeing a gasket of any kind. It doesn't help that courtesyparts part numbers don't seem to match most other nissan dealers. Thanks.

 

Yes. Looking at the 2003 FSM (page EM-10) there is a gasket between the precat and exhaust manifold.

 

I understand your confusion, as I went through the same process last year when assembling the parts I might require for disassembling and gutting my cats. Have a look at these links,

http://nissan4u.com/parts/maxima/us_...yst_converter/

http://nissan4u.com/parts/maxima/us_...llustration_2/

which are exploded diagrams and part numbers for A33B production dates 04-99 to 12-2002. You'll notice the front precat to exhaust manifold connection doesn't have a gasket, but the rear one does.The FSM agrees, as the rear gasket is illustrated, but nothing for the front. Also, the rear gasket is actually a crush ring rather than a gasket as the digrams suggest.
Cheers

 

Thanks. I actually finished the reassembly yesterday after gutting my precats (rear was clogged). Holy crap what a difference that made! I found the parts list that a local nissan dealer printed for me for my 2003 that included the cap converter and "washer wire" for the vq30, so it was him that ultimately steered me wrong and confused me. The really weird thing is that there is a similar 2 part gasket that I found inside the front precat underneath the catalyst and insulation. Obviously not something I needed to replace. So happy to have my car back on the road after spending a month and a half on jack stands