so i went to autozone at like 3am and got the Duralast Radiator C2310 for $215 and installed it and it all went smoothly as it should.
Luckily most of the stripping/cross threading happened to the female threads of the eBay radiator and not my transmission cooler lines because then I'd have to change them - they're flare nut and I don't have that tool and I don't think AZ rents that, and there might not be any slack if I cut them back for a new flare, and AZ doesn't even carry this part and the kit of them is like $150.
The female threads on the Duralast Radiator fit like a glove as they should I was even able to hand tighten them most of the way, there was definitely something up with the threading on the eBay radiator but they sell hundreds of these no problems.
I was thinking because the 3.0 6 cylinder is quite rare vs the 4.0, some parts aren't compatible (like the alternator I paid like 3X price for because the common one doesn't fit), so I was thinking maybe the 3.0 actually has different flare nut threading than the 4.0 and that the eBay sellers just assumed this radiator fits the 3.0.
But it turns out, on AZ's site if I change the truck to the 4.0 it still shows the Duralast Radiator C2310 as being compatible for both, so I'm baffled.
First time changing a thermostat, when coolant would get low with previous radiator it'd click/pop every few seconds when come to a stop, so I changed it and got the $4 paper gasket not the $17! one with the embedded red rubber gasket like the OEM, so as per most tutorials I used some red RTV high temp gasket maker paste I already had and didn't put much but it oozed around but only onto the outer rim of the thermostat and not to the actual component nor the tiny air jiggle pin which on this one is located inside the rim near the thermostat, the sealant had about 3.5 hours in 20 degree weather to set up but it still oozed quite a bit but I don't think it'll end up eaten away at by coolant and end up in the system possibly plugging something, but anyway first test drive I was getting hot air after car idling for about 10 minutes but temp gauge around 10% only, then drove 25 MPH and temp gauge was in middle as it should be at operating temperature but I was getting only cold air! But then ~8 minutes more driving and heat stayed on as it should so hopefully that's just a new thermostat needed to get broken in. I would have spent the $17 for the better gasket just to avoid any possible problems but didn't know about it until now.
Next, I'll idle the truck and hopefully the heat comes on so I can see if it didn't open on the initial coolant filling for the heater core section.
btw, swapping the fittings from the OEM radiator wouldn't have worked, the eBay ones are part of the grill etc and fixed.
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