PurposeElastohydrodynamic　lubrication　(EHL)　plays　a　crucial　role　in　high-speed　and　heavy-duty　gear　transmission　systems,　exerting　significant　influence　on　efficiency,　vibration,　noise　and　service　life.　This　study　aims　to　investigate　the　dynamic　response　of　gear　transmission　systems　under　EHL　operating　conditions.Design/methodology/approachAn　analytical　methodology　is　proposed　to　investigate　the　influence　of　lubricating　oil　parameters　on　dynamic　transmission　error　(DTE),　dynamic　meshing　force　(DMF)　and　vibration　velocity　of　a　planetary　gearbox.　Herein,　the　oil　film　pressure　and　thickness　are　calculated　by　the　relaxation　iterative　method　to　couple　the　EHL　model　with　the　dynamic　model　of　the　planetary　transmission　system.FindingsThe　results　show　that　the　DTE　decreases　significantly,　and　the　vibration　amplitude　of　DMF　and　vibration　velocity　also　show　notable　reductions　when　considering　the　effect　of　EHL.　In　addition,　with　an　increase　in　oil　viscosity,　the　comprehensive　stiffness　decreases,　while　the　oil　film　damping　in　the　single-tooth　meshing　region　increases　significantly.　This　leads　to　an　increase　in　the　peak-to-peak　value　of　DMF　and　has　a　greater　impact　on　single-double-tooth　alternating　meshing.Originality/valueThis　research　better　reveals　the　lubrication-induced　vibration　mechanism,　which　can　provide　a　dynamic　theoretical　basis　for　the　vibration　control　and　life　prediction　of　the　planetary　gearbox.Peer　reviewThe　peer　review　history　for　this　article　is　available　at:　Link　to　the　cited　article.