I had the 450+ settings with the line pressures maxed in the tune. It was... interesting. It felt neither like an auto or a manual, I have yet to be able to make a shift as hairy as that 4R made all the time. It was snappy, but being in other J-Modded cars using the more common mild to middle settings I wouldn't say mine shifted that much harder, but what it did was shift way faster in addition to it, and not in a way I'd call refined, it almost felt like things were going to break just puttering around town, and it made tuning shift points frustrating. Gave the car character though
Years ago a buddy and I did that on a 5.0 AWD explorer he had. In that situation, given that it couldn't spin the tires when it shifted, yes it did break things pretty quickly. About 5K miles after doing it, he was driving the car down the highway and all of a sudden the trans started locking up randomly. Luckily he got it to the shop, and we had a spare one to swap in, which we then did the mild j-mod to instead of the 450+ setting.
-91 Cougar LS, coming soon, complete overhaul
with a 427" Windsor.
-90SC 5-speed, MP2, coated rotors, double intercooler, 15%OD, ported heads, comp stage 1 cam, 85mm TB, 90MM LMAF, 80# injectors, soon to be transplanted into...
-90 XR7 5-speed black on black w/sunroof
-98 Mark VIII LSC, Procharger P600b, TR3650 swap and 3.73s.
-70 Torino GT Fastback project car. Needs EFI and a manual trans, but I'm not sure what motor to go with yet.
-"Your buddy Mike is INSANE!" -ClintD's dad