I have an L3830 with a BH90 sub-frame mounted backhoe.
When I put the backhoe on I remove the lower 3PH arms (and pull the center draw-bar out). You will need to disconnect the upper arms from the lower arms -- mine has a round wire loop keeper at these connections. Then follow the lower arms under the tractor (thay split into a "Y") and remove 2 bolts on each side. You do not need to remove the upper 3PH arms, just raise the 3PH to the top height and let the arms hang straight down.
I remove and reinstall my 3PH arms every time I put the backhoe on or off.
After doing it a couple of times it's not a big deal -- maybe 10 minutes total.
I hope this helps.
KW