We believe that the added harmonics and faster shifts caused by the twin disk units put the hub springs under too much stress causing them to break over time. If a piece of a broken spring gets caught between gear teeth it could be a disaster destroying your expensive gear sets. We now offer a modified spring that will never break for those that use twin disk clutches.
When we rebuild your transmission, please tell us if you will be using a twin disk clutch. We will include the modified springs at no extra charge! The picture below shows a couple of examples of broken springs. Far right is an OEM spring, middle and left are broken springs. The broken pieces of these springs can work their way out of the synchro hubs and do damage quickly.
Synchro Ring Mushrooming
This is becoming more of a problem with ridged hub disks like the twin or 4-6 puck disks. What happens is the outer part of the synchro ring at the keys mushrooms out and jams the ring in the synchro hub. We have found a fix for this by tapering the rings to allow for mushrooming without the risk of jamming in the hub.