STRANDED

@dragonsdofly I’m hoping you’ll post up a photo of your “vacation” spot before you hit the road, and if you could include the sheep, well, that would be icing!

You are in the midst of a surreal situation. It really feels like  a movie.

As a lifelong mechanic and diagnostic technician, I offer this simple, basic explanation of most troubleshooting principles:  
https://www.youtube.com/watch?v=MXW0bx_Ooq4

Enjoy
WilliamA 

Hey, @dragonsdofly... do you remember the Forum mantra...”pics or it didn’t happen?” Well... sheep? What sheep? 

Seriously, @Ratkity if nothing else, I’m thinking that a new badge of courage and endurance should be offered to @dragonsdofly from the Tab University.

Ahem, I believe that would be called the "Intestinal Fortitude" badge....in honor of those who persevere in the midst of diversity. I am in awe of how your spirits stay up @dragonsdofly, and how your sense of humor has stayed intact. Any word on when you can be "On the road again..." ..."just wanna be on the road again"  ????

tabiphile said:

dragonsdofly said:

Repayment of a family members cc for the tranny and other repairs. .......

You should not be paying for the transmission under any circumstances. They misdiagnosed the problem and threw a transmission into your vehicle only to learn that it was not the problem. Get a refund. Have them put your old tranny back in. Work something out before you pull away from there and head home. When a professional mechanic makes a major (and that is major) mistake, it is not your obligation to pay them. If you paid it on a card, protest the charges to your credit card company. Make sure that you have paperwork that shows what the real problem and fix were..plugged cats. Anyone that did not think look at the cats first on an 05 jimmy with that many miles is a fool...and it is not your obligation to make them whole. Seriously...sitting here 1,500 miles from your situation the problem was immediately clear from the description you offered and noting the age of your car. How you ended up with a transmission should be beyond any quasi mechanical persons imagination. Stand firm on this.

WilliamA, that was hilarious!!

and the head code... that’s easy for anyone to get....

Have you been off-road? I’ve had strange no code behaviors when I had lost a ground strap so parts of car intermittently would fail or reset. Wouldn’t respond to key at times.  Usually on debug list, but looking for torn straps only takes a flashlight and manual. 

I’m seeing a book coming from this experience...  At least a short story...

There are really only 3 basic causes for a plugged catalytic converter:
1. Too much fuel (bad plugs, etc)
2. Burning oil.
3. Coolant leaking into the combustion cycle (head gasket, etc)
let's not forget that it may be a combination of causes but the result will be melting of the ceramic coating within the converter that plugs the metal screen.  The commin thread is excessive heat in the converter.  Very often, the culprit condition may exist but not be bad enough to notice until another factor (like towing a trailer) exacerbates the condition, making it worse.  Modern control systems have gotten much better at mitigating and managing engine management to the point where such problems are not evident until an event (towing) radically alters the computers block learn integrator (yes, that's  a real thing. It's motor-eze for how your cars' computer "learns".)  The computer stores events (also called "start cycles") in blocks, then compares them to develop and average how much fuel, air timing advance etc the engine needs during a typical "start cycle".  The computer meters fuel etc to make the engine as efficient as possible within the given parameters.  Then, you pull a trailer...or dramatically alter the use of the vehicle in a way that falls outside of the specifications of the block learn, which is basically a rolling, constantly updating 2 dimensional array of numbers.  When that happens, the computer is unable to compensate enough and has to make the best choice available to protect the engine.  The computer default is to add fuel and retard timing to reduce overheating in the engine, which conversely causes overheating in the exhaust as there is almost certainly a rich condition caused by too much unburned fuel.  When this happens, it won't necessarily set a trouble code as the engine itself is still within the operating parameters of heat etc.  Given enough time, excessive fuel delivery will set a code but the computer is programmed to "be patient" and wait a number of data cycles before the bells and lights go off.  That's why an event such as this may happen without setting off a warning light.  
As an aside, it's within the realm of possibility for something as unconnected as transmission temperature to cause plugging of the converter.  The transmission sheds its heat through the radiator.  If that causes overheating in the coolant and thus, the engine, the computer will try to cool the engine by richening the fuel mixture and...voila...a plugged converter!  I am not saying that's the cause.  I'm saying that it's a "system" so apparently unrelated problems can appear as gremlins throughout that system.  When the mechanic tries to diagnose the problem,  the actual fault has disappeared altogether leaving only some failed component upstream or downstream as its "victim".  It takes very little time for an overextended system to be outside parameters long enough to plug the converter.  After the fact, it may be difficult or impossible to reproduce the fault.  Then, the mechanic must fall back on his or her own "block learn" (experience) to come up with a diagnosis.  It should also be noted that often, when the owner looks back,  he or she remembers something ignored that "wasn't quite right."
The sad mantra of we mechanics has always been not a matter of "if", but "when" we make the wrong call.
WilliamA