Stock LUV diff gears are 4.10 in 4x4 models. Your options are pretty limited though, as I think 4.10 and 4.56 are the only thing you are going to find for the front diff. You can find 4.56 gears in Isuzu Troopers up 1986 for sure, and some 1987s had the same front axle as the LUV. I have not done the swap myself but I think the third members should swap across, but if not the gear sets would.
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95 Isuzu Trooper Daily Driver
86 Isuzu Trooper reliable backup
77 LUV 2wd stock beltway blaster (resting)
79 4x4 LUV project: 2.6L, 5spd, 31s (eventually)
MEPR: Man, my 4x4 makes all other LUVs look good
