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Message: <blockquote data-quote="SPeace-ATL" data-source="post: 1574114" data-attributes="member: 36465">SHIFTER STOPS:I contend that it is not that the factory T45 (or even T5) shifter moves the shift forks too far, but that once the transmission gets all "loosened up" the slider can move further than necessary even if the shift rail did not push it that far due to slack in the forks, etc.  Shifter stops can limit the movement of the shift rail, but the forks, fork pads and other things can still allow the problem to happen.  Even WITH the shifter stops.Look closely at the shifter.  Under that Shifter Block in the shifter housing is a finger that sticks down into the "H" pattern to guide the shifter.  This also limits how far the shifter can move...  Yes, T45 forks love to break, but they don't break from the shifter pressing them too far.  These weak forks and weak shift plates are actually a different discussion. I'm not knocking shifter stops for these two transmissions.  Just be sure to adjust them properly.  Too loose and they don't do anything, and too tight and the synchro slider fails to fully engage causing premature synchro wear and popping out of gear.Okay, what goes on when the slider seems to have moved too far and the keys get stuck?   This is pretty common for the T-5/T-45/T-56 3-4 and the T-45 5-R and the T56 5/6 synchro.  Have you ever opened one of these and found the ends of the 3 stamped keys in the synchro hub to be completely sheared off?What has happened is when the slider moves a little too far the factory stamped steel keys in the synchro hubs tend to "pop up" on the side where the slider has uncovered the keys.  Having shifter stops can help this over-travel, but it may not solve the issue because once the parts are worn some, the fork pads have worn down, and all has become pretty loose you can't fully control the play in the synchro slider by limiting the motion of the shift rail. I have observed in bench testing that the cause of these synchro jams is often from the 3 stamped steel keys popping up.  If the slider moves a little too far in one direction it uncovers a little too much of the key on the other side of the slider.  the tips of those uncovered keys "live" in 3 notches in the synchro ring.  when they all 3 pop up simultaneously, the synchro ring is allowed to rotate.  At that point the synchro gets stuck in a gear.  The slider can't return to the neutral position because the keys can't et back in to the 3 notches in the ring.  The driver continues to "work" the shifter lever until they get it out of gear, but that process sheared off the tips of the 3 keys.  At this point, the opposite gear from the one that got stuck has no further synchro action.  Example, T45 stuck in reverse, keys shear off, then fifth gear has no synchro action. Stuck in third, the keys shear off and fourth gear has no synchro action.  Sometimes this process actually breaks the forks themselves.I have noticed that the aftermarket solid keys available for these synchros tend to not pop up when the slider moves more than necessary.  If they don't pop up, they don't release the synchro ring to rotate, they don't get jammed, and the problem of shearing off the keys doesn't happen. All these years people have been blaming the stock shifters for breaking the forks by pushing to far, but I contend that the original stamped steel synchro keys are the root cause of this problem.  For this reason I highly recommend the solid keys  in the 3-4 synchro hubs of the T-5, T-45 as well as the T-56.  Likewise, for the 5-R slider for the T-45 as well as the 5-6 slider in the T56.  All of these locations use the same original stamped steel keys...   While solid keys are available for the T-45 and T-56 1-2 sliders the stamped keys in those positions really don't give much trouble.   Note that the early Corvette T-56 1-2 synchros do have solid keys there from the factory. Stan</blockquote>