My backseat is out now, so can someone give me a measurement from the top of the back seat to the inside of the tailgate? I'm looking to get a storage box for the back and need an idea how deep I can go with the backseat installed. Thanks!
Here are my measurements, but read my caveat before using them:
Measured at the top of the tailgate, the distance from the inside edge of the tailgate to the back seat is 25", less 2" for the depth of the latching mechanism, thus a box this height could be about 23" deep in my jeep.
The top of the seat is approximately 7" higher than the top of the tailgate.
Measured at the top of the seat, the distance to the plane of the inside edge of the tailgate is 23", less that 2" for the latching mechanism, for a net of 21". (The rear seat back is angled back a bit, hence the shorter dimension.) A box this height could be no more than about 20" deep in my jeep.
Caveat
My dimensions are going to be different than every other LJ.
I drilled new holes in the factory rear seat brackets and moved my factory rear seat forward 1.5-2" before I built my interior cargo rack for my LJ. I did this so that the gear I needed to fit behind the seat would fit better and because I was more concerned about storage than leg room for passengers. I cannot recall the exact distance I moved the rear seat forward, but my recollection is that since the LJ has 2" more rear seat leg room than the TJ that I moved the seat forward an amount that corresponded to the most logical place to drill new holes that would put the seat closest to the legroom provided in a TJ. It wasn't exactly two inches, but close.
Further Caveat
Pay attention to the angle of the rear window of your soft or hard top.
When I built my rear storage rack, which is close to the height of the top of the rear seat seatback, I determined that after the rear seat was relocated 19" was the maximum depth so as not to have the rack or cargo ever hit the angled rear window of my hard top. (The taller the box, the shorter the dimension from front to back must be in order to clear the rear glass.) My rack is 17" deep to provide yet one more inch clearance fore and aft.
Suggestion
Move your rear seat mounting brackets, if necessary, to allow the box you really want to fit the new space rather than try to find the one and only box in the world that will fit the space you currently have.