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Discussion Starter #1
Does any body know what the exhaust gasket part numbers are for the 2006 3.7 commander?
I had to pull the catalytic converter, before I install the replacement I want to make sure I can locate the correct gaskets.
Some kits have the gaskets this one doesn't.
The kits the have the gaskets look like three ring gaskets, 2 small, 1 big. I assume intake down pipe and y pipe to muffler.
When I look it up online I see several gaskets listed for the commander two or three that I'm sure done go on the commander.
Felpro has one ring gasket but I'm having a hard time figuring out what it does on this vehicle .

Thing is I didn't notice any gaskets on the old parts, cold be melded together I guess.


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Thing is I didn't notice any gaskets on the old parts, cold be melded together I guess.
It's also possible that there is no gasket at all in the design.

Past experience with Chrysler exhaust systems is that they generally don't have a gasket between the manifold and the catalyst or Y pipe. Look closely at the inlet surfaces on your old part and the new one. If there's no gasket on the old part, and the new part is identical, put it together without one.

It can be a bear to get both sides seated properly on the exhaust manifolds without one side leaking (loudly). Don't ask me how I know this. :laugh2:

The downstream side might have a gasket. Again, check for remnants (and scrape anything that remains away from the mating surfaces of the parts you are reusing).

Just for reference, I know for a fact that the older 5.9L, 5.2L V8's and 3.9L V6's in Dakota pickups and Durango SUV's had no gasket between the exhaust manifold outlet and the upper cat/Y pipe inlets. It's a Chrysler thing.
 

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Discussion Starter #3
I was just checking, it looks the flanges are rounded so maybe no gasket is required after all.

I thought when I swapped the motor there was no gaskets for the down pipe.
I'll compare the new converter when it arrives.



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Discussion Starter #4
No gaskets for the 2006 commander. All the parts catalogues are wrong.
Thank you Racer X!

Here are a few pictures of the fittings.
the flange for the muffler

The pipe from the catalytic converter to the muffler.







The exhaust manifold to the down pipe going to the catalytic converter.


Should have this wrapped up tomorrow, I'll post a quick step by step for anyone else who may come along with a 3.7 in need of this job.

Honestly on paper it's straight forward in real life it's a PITA. Mostly because of stuck exhaust bolts, which were a pain in the motor swap. For any looking at replacement parts the magnaflow looks real nice it's also two piece design which made reinstallation easier. The factory one piece design is cumbersome to remove and difficult get out from under the jeep, took lifting it a few more inches to come free of the frame.

Honestly if you know an decent shop I'd let them handle it, if it's not too pricy. I'd swap the motor on a commander again, just wouldn't want to do this job if it were avoidable.

Hopefully tomorrow it's all finished and I'll know how well the new cats do and any difference to how it sounds and runs.

Cheers!


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OK final wrap up

Magnaflow is easier to install for a DIYer than the OEM, however the OEM is a better design for the upstream O2 sensor placement, magnaflow was slightly lower just enough to interfere with the transmission lines. Other issue was the OEM is flared to keep the bracket that bolts to the exhaust manifold in place during instillation.

Functionally, I see no difference. Actually the engine is running very smoothly right now, after computer reset, new catalytic converters and all four o2 sensors.
Of course as we establish earlier there are no gaskets needed despite what the parts catalogues say.

Tips for removal:
Pretty straight forward, if you're doing it in your drive way ramps are nice but do no offer enough clearance to pull the OEM catalytic converters out as an assembly.
To get better access to the bolts on the exhaust manifold remove the tires and pull the fender linings.

Unplug the O2 sensors. I cut the passenger side upstream because the plug was behind the transmission dip stick tube.

Support the transmission then remove the crossmember,
8 bolts hold it to the frame and I believe 4 holt the transmission mount to the crossmember.
Depending how you're supporting the vehicle you may need to plan this step out because once the crossmember is out you'll need the jack to hold the transmission in place. If you only have one floor jack you will not be able to lift the front end up higher for more clearances to remove the OEM Cat or front tires to access the exhaust bolts.

You'll need a 16mm wrench with ratcheting action to get the two bolts that hold the exhaust hanger on the transmission. Lowes has a decent quality wrench.

My FSM had only one bolt there, there are two and little clearance to get at them, so you'll need the thin profile of the wrench to get them off.
The catalytic converter hanger just slides off, however it has to be unbolted to remove the catalytic converter, there is not enough room to slide off on the vehicle. If you having a hard time with those bolts you can lower the transmission a little.

Tips for Instillation:
The two piece design is easier to line up and reinstall. But has the draw backs I mentioned earlier. If the bracket for the exhaust is slipping down far enough to make lining up the exhaust bolt difficult use a strip of masking tape below the bracket to keep it in place. I used the tape intended for masking off areas for painting so it was real easy to remove.

I put new exhaust bolts and nuts just because it is such a pain to get them off.

Crossmember was straight forward, if it's not lining up try lifting the transmission up or down until it easily lines up with bolt holes on both sides.


It's not a complicated job just labor intensive as you get into it.








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