<![if gte mso 9]><xml><w:worddocument><w:view></w:view></w:worddocument></xml><![endif]><![if gte mso 10]><style type="text/css"> Style Definitions */table.MsoNormalTable{mso-style-name:"Table Normal";mso-tstyle-rowband-size:0;mso-tstyle-colband-size:0;mso-style-noshow:yes;mso-style-priority:99;mso-style-qformat:yes;mso-style-parent:"";mso-padding-alt:0in 5.4pt 0in 5.4pt;mso-para-margin-top:0in;mso-para-margin-right:0in;mso-para-margin-bottom:10.0pt;mso-para-margin-left:0in;line-height:115%;mso-pagination:widow-orphan;font-size:11.0pt;font-family:"Calibri","sans-serif";mso-ascii-font-family:Calibri;mso-ascii-theme-font:minor-latin;mso-fareast-font-family:"Times New Roman";mso-fareast-theme-font:minor-fareast;mso-hansi-font-family:Calibri;mso-hansi-theme-font:minor-latin;mso-bidi-font-family:"Times New Roman";mso-bidi-theme-font:minor-bidi;}</style><![endif]><p class="MsoNormal">Whenever Igive my Tornado (which is brand new!) a little bit of throttle it seems to just stutter and cogg. It sounds like the spur gear is grinding the pinion. Icheck the spur gear mesh and it is perfect. I also opened both of my diff's up and made sure it had some grease and no debris. Itook the diffs out and twisted them with my hands and they were really smooth. I also can roll the buggy with my hands and Idon't hear anything. Iknow it is the drive train because Iput a different motor and ESC on it to make sure it wasn't a bad motor or ESC.
Anyone have any ideas?</p>

well, cogging is pretty normal when giving only a smal bit of throttle. sounding like the spur is stipping till the car/buggy gets rolling.
since you already checked the drivetrain and found nothing, id say its just the setup. lowering the gearing can reduce cogging, but there is nothing wrong with alittle cogging.