CamGTP

Pretty straight forward really. Remove the wheels, then the drums. Unbolt the cover plate on the rear axle, remove the single bolt holding in the pin on the diff, slide the pin out. Push an axle in and remove the c-clip and slide the shaft out. Repeat for the other side.

Completely normal. Hot oil pressure of 20-25psi is well within spec. Every single LS or LT engine I have own has idled at around that oil pressure when hot.

Here is the part number off the GM site. Contact a local dealer to see if they can get you one. https://www.gmpartsdirect.com/oem-parts/gm-torque-converter-17804388?c=Zz1hdXRvbWF0aWMtdHJhbnNtaXNzaW9uJnM9YXV0b21hdGljLXRyYW5zbWlzc2lvbiZsPTUmbj1Bc3NlbWJsaWVzIFBhZ2UmYT1jaGV2cm9sZXQmbz1zaWx2ZXJhZG8tMjUwMC1oZCZ5PTIwMTQmdD1sdCZlPTYtMGwtdjgtZmxleA%3D%3D Otherwise you could contact a torque converter company and see if they can match you up with a converter that is just like the stock 6L90e. Summit racing, JEGS, Circle D converters may all have what you want.

That is normal. That is the flex fuel harness that comes on every truck but your truck does not use it. The thing in the end of the harness is a dummy plug just to stop water and crap from getting in there.

I see tons of guys using half ton trucks for hot shotting or local Courier services. Most of them have toppers and some pull smaller trailers like the size of a car single car hauler. If most of the stuff you pick up fits in the bed or fits on a trailer like that and weights less than 6,000-7,000lbs, it should do just fine for a while. Do a little prep on the truck before hand and go for it. Good tires, proper pressures, remove the transmission thermostat to make sure the transmission stays cool, use tow/haul anytime the trailer is hooked up.

I highly suggest you leave the cats. For one you'd need a custom tune to delete them and they act as really really good resonators to stop the horrible rasp and drone that can come without them. Leave the factory resonator for now and just do the muffler. To me it's better to do one thing at a time than 2 or 3 because you can actually find out if you like the sound before going to another step.

To answer the question about the block heater, whether it was serious or not. The factory block heater doesn't work unless it's below 0 degrees Fahrenheit so that is kinda out of the mix for the majority of the time. Only the engine coolant would be warmed and the transmission fluid might warm up slightly quicker if you just jumped in drove off. I started my truck this morning as well and it like 15 degrees, let it run for 10 minutes and the transmission temp was 66 degrees. Drove my 4 miles to work and it got to 90-95 degrees with no thermostat. It acts just like my 2012 did without it. I didn't read much of the other stuff in this thread lol

P0700 just points to a general fault and not a direct fault. That code just means there is a problem. If the other code is a P0741, that is the direct fault and likely the cause of your whole issue with the transmission. Torque converter failures are one of the most common issues with the 6L80e.

Not much at all because the part is above the oil level in the pan.

The AC will cycle if the knob is turned to the defrost or the floor/defrost combo.

I'd try the $10 thing first.

That P0741 code still points at torque converter failure.

That is for sure an exhaust leak.

If you prime the system like 3-4 times, does that make it start faster?

It's hard for me to grasp the exact points you're explaining without pictures. Most leaks are the pan gaskets, the rear tail housing seal on the transfer case where the driveshaft goes in or possibly the front pump/torque converter seal inside the bell housing. That leak tends to come out of the inspection cover/plate on the bottom, it's roughly 2 inches in size.

My opinion is that it needs a torque converter. Depending on mileage of the truck it probably should have the rest of the transmission gone through as well.

Do these codes come back on immediately or do they take 10+ miles of driving? Also if it's right away it's just coming up on the scanner and not the cluster right? Some of those codes are permanent codes and do take several drive cycles to clear. I personally wouldn't replace the cats right away again. I'd try to space the rear o2 sensors out of the exhaust stream to see if that stops the codes from coming back.

I like to drive the vehicle hard to clear out the exhaust. Not only to get the exhaust really hot but to test the work. Because if it's going to fail it will fail, so I might as well test it under some "slightly extreme" conditions.

Amsoil or Valvoline is what I use or tell people to use. It works great. Lots of people like Redline oil as well but that seems to be harder to find at most auto parts store.

Correct, many bearings use that torque settings to preload the bearings. I only run my impact down until it's tight then torque it the rest of the way. All the other stuff gets the impact treatment.

They have not invented the technology yet for me to teleport through my computer and check under your truck to see where the leak is. So for now I do think it's best that you crawl under the truck to see what you might be dealing with.

I'm pretty sure my impact gun stopped at those exact specs too, I know my tools pretty good. The axle nut and lug nuts are the only thing I torque lol. From my experience, the bigger the wheel the faster the hub fails. Took 100k miles for me to replace one on my truck with 18's.

You'll just be driving into another ticket once you go with long tubes and catless exhaust. The amount of drone and rasp will drive you nuts. You'll be yelling just to talk to your passenger unless you're coasting.

I think you kinda figured out the problem already. Check some stuff out in the rear end. Like a broken shackle, loose leaf spring bolts or something like that. If the rear axle is shifting, that will cause the whole truck to push hard to one side.