No motion for new trial or request for findings of fact and conclusions of law shall be held ineffective because prematurely filed; but every such motion shall be deemed to have been filed on the date of but subsequent to the time of signing of the judgment the motion assails, and every such request for findings of fact and conclusions of law shall be deemed to have been filed on the date of but subsequent to the time of signing of the judgment.
Tex. R. Civ. P. 306c