I noticed the left rear is lower than right rear after I bought my 02 Supercrew a year ago. It's only 3/4 inch gap. Didn't really bother me that much. After buying the new four tires on it recently, took it to the alignment shop. They didn't notice it during alignment. I reminded them about the gap. The guy said he can add 3/4 inch shim to left rear to even it out. WOndering what's that? Is it common among your F150's? I thought about the rear spring being weak, but it's pretty young when i got it at 22K a year ago.

 

its normal due to the gas tank and most weight go on that side, its one of those defects. ive learn to deal with it. it gets worse with a full tank of gas