727 Tranny Leaks

[Bob Kincaid]

Have a 727 behind a BluePrint 408 Crate Engine. In a '73 Dart Sport. Plenty of power etc. Of late the rear Trans Seal leaks and fluid leaks out where the speedometer cable goes in. On a 250 road trip at 70mph (turning about 2700 rpm), I can lose a quart of fluid. BTW it blew off one of the rubber hoses where tranny lines connect to radiator about two years ago. Replaced hose and used extra clamps and no further problems there. This Tranny has been rebuilt twice since I bought the in 2006. It has had seals replaced in the last 5 years. I hesitate to take it to Ammco as they don't have the best rep for Classic Cars. Any ideas or suggestions on what to try next?

 

[mopowers]

Any ideas or suggestions on what to try next?

Didn't you say the "rear Trans Seal leaks and fluid leaks out where the speedometer cable goes in?" I'd start with replacing those. They're are simple and cheap to replace.

 

[Dubob]

Also be aware of the bushing in the tail shaft of the transmission. If it’s worn it can let the driveshaft yoke walk and leak. Don’t know how thorough the rebuild was. Make sure the selector shaft seals aren’t leaking. They’ll let fluid move and can be hard to diagnose.

 

[moparlvr166]

If you remove the tail housing to replace the tail bushing, you might as well replace the O-ring for rear band pin and make sure the 2 screws under the mount that holds the cover plate to access the snap ring, holding the extension housing to rear bearing.