I had this problem when I did the extended travel coil overs from Radflo. I suspect that the shocks were built with too much extension in them as could be the case with yours. You got to figure all of these are being assembled by hand - there's bound to be an assembly mistake, order misread, etc.
At full droop mine would bind and would create an issue when driving. Aftermarket axles were of no help as the inner CV joints were much less tolerant of articulating. Diff drop really wasn't much of a help, and really only served as a band-aid that
slightly alleviated the binding (never liked diff drop kits anyways). I ended up going to a machine shop with my OEM's and having them cut back the inner CV joint by about 1/2" and re-machining the notch grooves for the CV boot and clamps.
Adjusting the coil over lift height will not help much as the shock will still allow bind during down travel no matter what.
Here's a discussion of my issue over on the "other" forum:
Toyota 120 Platforms Forum
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2007 4Runner Sport Edition V6 4X4 - Natural White -
Perf: Doug Thorley Long Tube Headers | 4.56 Gears ARB Front / TrueTrac Rear
Off Road: Fr: Bilstein 6112 w/1/2" Toytec Spacer / Rr: MT ICON Long Travel | JBA UCAs | VTX Rogue 17x8.5 -10 | GY Duratrac 285/70R17 |
Rear Diff Breather Mod | 1" Toytec Body Lift | Custom Cut Axle Joints
ICE: Auto Pumpkin 10.1" Android |
3.5" Tweeter Mod Exterior: Quad Bi-Xenon HID Retrofit
2019 4Runner Limited 4x4 - MGM - Hers |
Ironman4x4 FCP's & UCA | Fuel Rebel 20x9+1 | GY Duratrac 275/60R20 | Victory 4x4 FLRR