C-ONE Sports Diff. cushion Brand C-ONE Motorsport (Japan) Website C-ONE.co.jp Part number CB5229-ST205 A common problem of all GT-Four models is a worn out rear diff. mount. You can upgrade the flimsy stock mount to a beefier version - several aluminium and rubber options are available. I decided against an aluminium one to prevent extra drivetrain stress (specially when I put my carbon prop. shaft in) and went for the rubber C-ONE version. The stock worn mount next to the fat ass C-ONE mount Related links How to replace the rear diff. mount Modifications - Chassis Top