sdhicks

I have a 2002 Grand Cherokee Overland with the 4.7l HO engine and it has the 5-45RFE transmission. I bought the car a couple years ago to restore it and it runs great for the most part. The problem I'm having currently is that there's a delay in going into forward gear when it's cold, specifically when it's below freezing. I don't drive it very often but when it's warm or hot it shifts perfectly normal.

A little history on the vehicle:

The vehicle has over 100k on it and the engine was not working when I got it but it's been completely rebuilt and runs like a champ now. Before I even bought it I checked the transmission fluid and it was super clean, just a tiny bit darker than if it was brand new fluid. There were no contaminants in the fluid at all when I dropped the pan and changed out the filters. I very carefully looked for debris in the pan like clutch plate fibers or metal flakes and I also looked inside the filters with bright lights and they were clean. I used to rebuild automatic transmissions on BMW's so I'm familiar with common failures of transmission clutches by overheating and and abuse. I also did a complete flush of the fluid, enough to clear everything including the converter. I'm fully equipped to do any service I need to including pulling the trans and rebuilding if needed so doing a flush was not a problem. I used the correct ATF+4 fluid. I've been checking it frequently and it's very clean and shows no sign of contamination or discoloration.

I had a P0841 code so I bought one of the pressure tester adapters from ATS Diesel and checked the pressure. I also bought a brand new OEM line pressure sensor. I tested it cold and ran it through all the gears and reverse. According to the specifications the pressure should hold about 120PSI in neutral and all forward gears and the reverse should hold 180. The pressure is perfect. No dropouts or sudden loss of pressure in any of the gears. The sensor was hacked in from some previous repair and damaged so the replacement was necessary but didn't improve the problem.

My questions are these:

1. Am I correct in assuming that if the pressure is at spec, that there can be no internal leaks?
I'm specifically referring to the large rubber o-rings or seals that contain the pressure on the clutch packs. The valve body is obviously "before" the clutch packs so any major pressure drop would indicate an internal leak that could be either cracked passageways in the valve body or leaking clutches as far as my understanding tells me but I'd like to have another opinion on that.

2. With the information I provided is the valve body and/or solenoid assembly the best potential suspect?
I've been told by several different sources that the valve body and solenoid assembly are the most common problems on these transmissions with delayed shifting. I'm willing to buy a rebuilt valve body because the cost is reasonable and the company I'm looking to purchase it from sells the complete rebuilt one with Sonnax shift valves and with a new solenoid assembly that has a lifetime guarantee.

Thanks in advance for any help!