Halok

2004 4.7L WJ Special Edition, factory towing package, supposedly 95k original miles one owner (now two). I'm not sure which issues are related here so I'll start from the top. I purchased this a few months ago with a known trans issue: the Drive position only used third gear, I could manually select second, but there was no first. Sometimes on a cold start by selecting the drive position the engine would die immediately. I replaced the valve body once I drove it home and everything worked fine. Pulled my 16' boat 100 miles each way for a weekend trip and drove it 20 miles daily for a month with no issues. Next time towing the boat I got a trans over temp light after 30 miles at 70mph on the expressway, about 80 degrees Fahrenheit ambient temperature. A quick google search resulted in recommendations to use O/D off when towing so I did that and kept it at 60mph. No issues for the next couple weekend trips towing with O/D off and no issues daily either. I should note that I also have a 2003 Overland which I have towed the same boat for three years and never had trans over temp and always used overdrive so I was surprised that the Special Edition was having a problem.

Recently 100% of the time on a cold start (more that 6 hours sitting) the transmission will not engage a gear properly when selecting drive. Reverse is super slow to engage but usually works within 5-10 seconds. With drive I could leave it selected for 5 minutes and it would never engage first gear or any gear unless I rev the engine 1500-2000 rpm. When I do that it will clunk into 1st gear & chirp the tires while pulling away. If I then keep the rpms on the low end around 1500 or so it will fall in and out of gear three times before holding it. If I keep the rpms higher around 2000 it will hold the gear on the first try. The vehicle will continue to shift through the range as normal when driving through my neighborhood, stopping very briefly at stop signs until I get to a red light and stop for more than approximately 20 seconds. After a prolonged stop when attempting to accelerate away from the green light it will rev up and clunk into gear, but now it will be third gear, and will be stuck there forever until I turn the key off and restart the vehicle. Once I do that It works perfectly forever until it rests for more than ~6 hours, but it will still get too hot if towing without disabling overdrive. The crazy part to me is I could let this thing start up and idle in neutral and warm up for 20 minutes and It still has the problem, but even a cold start with a 30 second drive around the block followed by a restart fixes it for all day. Its like it needs to bleed some air out of the hydraulic system or something?

I'm very mechanically inclined/experienced but my weak point is automatic transmissions so I'm begging for some help on this one. I feel like there is no mechanical issue with the bands/clutches because it eventually works fine. The fluid is full, if anything it's a bit overfull. That leads me to the valve body but why only have problems on a cold start? If it is the valve body and I fried it by driving too hot, and maybe that's what happened to the previous owner, than what is causing the trans to get too hot? I do have an SES light on with the following codes:
P0733 Gear 3 incorrect ratio
P0731 Gear 1 incorrect ratio
P0740 Torque converter Clutch Circuit/Open
P1389 ASD relay???

Oh, and finally sometimes the engine won't restart when hot, the starter cranks SUUUUPPER slow the hotter it gets, but I googled that too and looks like from a heat soaked starter (surprise) so I'm not worried about that unless it's related I've already got a new one ready to throw in. What I want to focus on is first the shifting issue and possibly the over temp issue. If i were to throw parts at it i would get another used valve body and install an aftermarket trans cooler and bypass the radiator in case there is a restriction somewhere causing all of this. But before I do that i figure I'd ask the experts or someone who has solved this problem in the past. Thanks in advance for any feedback!