On both flushes I used new 5w-30 oil and filter, got the oil nice and hot before performing the flush.
I used Liqui Moly Pro-Line Engine Flush with Euro lubes exclusively. I got the best results in my wife's 2017 Hyundai Santa Fe because I had Castrol 0W-40 in there, then refilled after the flush with M1 5W-40, ran it for a week, dumped it, and refilled it again. There were a few varnish spots here and there, including the oil filter plastic housing from a dealership oil change way back (bulk "synthetic" Shell they claimed), and it's all gone now. I never used Liqui Moly Engine Flush with ILSAC GF5/GF6A lubes.
Where did you buy your lubegard. Rock auto?
I got it from Amazon, and funny enough, I still have 2 quarts of the stuff.
The esters in lubegard trans protectant did a great job of cleaning out the 6 speed in our grand caravan a while back.
I have no doubt about it, I use 4 oz. of Lubegard Platinum in my BW44-44 transfer case in the Ram 1500 along with Amsoil ATF just to boost the cleaning abilities of the fluid. When I dumped the factory MobilfluidLT it was clean, but I wanted to rinse it out, lol. When I do my next change I won't add Lubegard to it.
The Lubegard engine additive is a different story though. I only used it with ACEA A3/B4 engine oils. I doubt that it can add anything to those as they already have a beefy additive pack. I think that it can help "lesser" oils, however, it can't improve upon a good quality synthetic. Engine oil formulation is tricky, and you risk destroying the balance that exists in a fully formulated oil when you add Lubegard to it. I guess that's why I've seen people claim that Lubegard quieted down their HEMIs after they added a 15oz bottle to their Quaker State or Pennzoil 5W-20 filled engine. The HEMI is set to cook itself to death from the factory, at temps of 220F~230F just driving around town. So of course in that scenario, Lubegard added to a weak oil will quite the notorious "HEMI tick." I installed a 180F thermostat and removed 8 of 12 grille shutters, so now I'm hovering at 185F~190F all day long. When towing, oil temperatures average 210F. So I'm barely hitting full operating temperatures. I hope this makes sense.
Honda dropped the ball on reliability because they cut too many corners. I wouldn't buy a Honda, even if prices were sane. They always seemed overpriced to me. The 6-speed transmission in the Grand Caravan is made by Hyundai and is known to be very reliable. The downside is that it's set to constantly cook the ATF at 200F~210F when driving gently, never mind when you step on it. I just changed with 3 drains and fills, each, the ATF in our Hyundais to AMSOIL "ATL" fluid. They run really well, but the fluid I drained at close to 40K miles on each was dark brown on the 2018 and pitch black on the 2017, and they are both driven gently (look in my sig).