I believe there is a diagram of the 3 speed column on the LMC trucks site (
www.lmctrucks.com ). It should be helpful in your search . Is the play in the column itself or in the suspension components ? Have someone turn the steering wheel while you watch the steering shaft under the hood . Then get under the truck and have them turn the wheel back and forth . See if there is any noticeable looseness in any of the components ( idler arm , drag link , etc. ). This may help to figure out the problem . Good luck !