A standard tranny that pops out of gear?. What gear? If it is dropping out of high gear, it is either the "cogs" on the
gearset that engage the slider ring being worn, or the bellhousing alignment. If it is dropping out of an intermediate gear, then it is either the "cogs"
worn from previous gear grinding or harsh engagement (often due to blocker rings Known as "Synchro's" getting weak) or the gear's fit is ever so
slightly loose where the gear rides on the mainshaft. If the particular gear is running even a tiny bit crooked or wobbly, the slider ring that engages
the gear cogs will "walk" off the contact area. This is due to (as the shaft rotates with a crooked gear) deep engagement, then shallow engagement,
deep ,shallow, deep, shallow, until the shifter ring is actually pushed off the cogs it engages with. Often you can see the cogs worn into funny
shapes, eventually resulting in a gear-jumping tranny even after the alignment is corrected. If the "cogs" are still shaped correctly to encorage
engagement, then usually a bushing or bellhousing alignment will be a permenant cure. (Only IF the cogs are still in shape) The shaft centerline HAS
TO BE on the same centerline as the crankshaft. VERY VERY VERY IMPORTANT!!!!! The old "backyard" method of bellhousing alignment IS
NO GOOD. IT IS HARMFUL NONSENSE. There are people who swear that they can "dial-in" the bellhousing or torque convertor by rotating,
then tightening a bit, then rotate, then tighten, then rotate ETC. They are only kidding themselves. IT DOES NOT ALIGN! The ONLY way to
align a Stude housing is to put a dial indicator on a magnetic base on the flywheel surface and the dial plunger in the bellhousing hole, rotate the
crank and check the "offcenter" reading. Move the housing to line up with center, no more than .004 to .006 runout, and drill new dowel pin holes
to hold bellhousing in place. IF YOUR MECHANIC DOES NOT DO THIS, IT WILL EAT TRANNYS!!! When we make our GM Automatic
Trans Conversion Kits, we use a large diam hardened, precision ground shaft bolted in the main bearings of a bare engine block, and running
through the center bearings of a GM trans case. That is why our alignment piece that comes with every kit, grabs the crankshaft tightly during
installation; It is important to align the shafts. David LeVesque (cardboard boat builder extraordinaire) see WWW.GCBR.COM