I have a 2005 NH TC40D that the rear mounting bolts for the transmission case keep backing out tighten them several times, the leak finally would not stop found crack in the transmission case, when the tractor was split the top three bolts inside the case that you can not see had backed all the way out and was about to fall into the gear box. The crack was hard to notice when it was bolted in once the bolts were all out the crack opened, the dealer claimed they have only seen cases crack when lifting heavy loads with the bucket, this is not the case here, the replacement case cost $1,600 plus my labor, the dealer wanted over $5,000 to do the repair. Word of warring if your bolts in the transmission case work loose remove the platform and the transmission top inspection plate check those bolts, I would replace them with new and Loctite
