Is your d4 light flashing, is your cel on? If it is you have a code for the transmission. Honda will usually help with a transmission replacement us the numbers in the back of your owners manual, but you first have to take your van in to dealer and have it checked out.
Do some research on stall testing the transmission this can tell you if you have a slipping clutch pack. You may also consider draining the fluid threw a paint strainer and seeing if you get any debre out of the fluid.
As for the shock take a look at your engine mounts.