I had lately recieved in my new rear subframe, from a 2001 FD, with the 4.30 rear diff. I bought the entire rear subframe, diff, axles, rotors, etc. Anyway, while moving it around, I noticed an odd difference between sides. While laying on the ground just as it would bolt up in the car, if I grab the passenger side brake rotor, and pull it up/down ( as the wheel would travel up-down), its pretty easy to make the suspension go through its travel, only really feels like Im lifting the weight of the hub and rotor/caliper. However, if I try and lift the drivers side rotor up, the suspension does not want to travel, and I will end up lifting the entire subframe up before it does anything. I know it sounds a bit odd, and not even sure if it should be something Im worried about, but I spent a good chunk of change on this setup ( also got the trans), and Im just wanting to make sure nothing is wrong before I bolt it up in my car.

 

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it could be bushing binding on the driver side or the bushings are failed on the passenger side...hard to deduce from the information given.