seal..etc., it is CRITICAL that the crankshaft be BLOCKED from moving forward.  If you do NOT block the crankshaft, you run the risk of the crankshaft moving forward a small amount. This can result in a HIDDEN thrust washer moving downwards and off its two locating pegs. If that happens, the washer will not align back on those two pegs as you tighten the 5 flywheel (or clutch carrier) bolts, and you run the risk of MAJOR DAMAGE to the thrust washer….and even MAJOR damage to the engine casting.   The crankshaft will begin to freeze up as you tighten those 5 bolts. There is another similar thrust washer located rearward of the engine casting, and it can also come off its pegs.  I install it oiled, which acts like mild glue when installing the flywheel (clutch carrier) You REALLY do NOT want any of these problems happening. If you forgot or did not know about blocking the crankshaft, and you want to know IF the crankshaft has moved, there is a link near the end of this article, which will give you the information. The dimensions need to be as shown, in order to know that the crankshaft has not moved. The only way to see and get the hidden thrust washer back in place, if it has moved off the pegs,