D4 7U dozer

Hi , can anyone Help . Have removed top off gear box and wanting to know if gears can be removed from transmission from the top with out splitting dozer . The second shaft (counter shaft ) front gear is flopping side to side ,I only had top gear and reverse as they are straight through. Not sure if this gear slides on a keyway , spline or bearing stuffed. Its the gear closest to clutch . Looks like i could disconnect clutch and can get to bolts holding shaft ,can any one help not much info...

D4 7U dozer

D4 7U dozer