got a pic?
there are stickies in the forum that has a PDF for identifying.
however for 1990, assuming you have a 740 A or a 740B your drive should be a DP-B. maybe a DP-A.
pull the drive and get the serial number from the casting (between the steering helmet pin and the bellows)
most likely the shift linkage needs adjusting. could have also broke the splined sleeve connecting the trans to the lower.