727 steel front planetary gear.. need help

[darryn smith]

Hello just joined the forum does anybody run steel front planetary gears in there 727 bb and have they had any trouble. Who makes a good one. Have stripped 2 alluminium oem ones getting tired of pullen auto out.. No one makes them in Australia. Thanks dazza

[John_Kunkel]

Welcome to the board.

Spline failures in the front planetary are often the result of mismatched splines. The pressure angle of the spline on the output shaft was changed in '76 and again in '94, if the later planetaries are installed on an earlier output shaft the mismatch of spline angles will cause the splines to fail much easier due to reduced contact surface. An easy way to check is to install the planetary on the shaft and then shine a strong flashlight from the backside and view from the frontside...any discrepency in the spline angles will show in the light that comes through.

If however, the failures are simply due to too much power the steel is the way to go; there are several American builders that offer steel planetaries, I would recommend John Cope at Cope Racing Transmissions, I'm pretty sure he will ship to OZ. The quality is the same no matter the source.

[darryn smith]

Thanks john, 727 is 1968 factory 4 planetary front and rear, billet drum 6 clutch, non leak servos,  alloy rear 4 clutch drum bolt in sprag, its stripping on first to second manual change  car is 68 charger very heavy, 3.23 lsd 28inch tall mickey thompson  2500 stall, add 500 stroker and a f1r procharger and 10lbs boost a lot torque on such a small piece of alloy...on utube BLACK BLOWN 68 CHARGER, . I shall call cope. This is a great sight tuff cars enjoy checking on whats going on in other guys sheds...Dazza

[metalstorm440]

I am using the A&A planets that cope will probably be selling you and they work great and cope I am sure will spend the time to be sure you are getting what you need.