GMC 12637710 Seal Assembly, Crankshaft Rear Oil

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At the time of publication, the rear crankshaft seal is supplied as an assembly consisting of the oil seal and housing. The manufacturer recommends using special studs EN 46109, seal alignment tool EN 47839 and handle J 42183 to ensure correct alignment of the seal. These tools are available through SPX Tools. Disconnect the cable from the negative battery terminal. Remove the driveplate. Remove the oil pan. Remove the retaining bolts, then remove and discard seal housing from the engine (Rear crankshaft seal housing bolts). It may be necessary to use a knife to cut the sealant away from the joint between the rear crankshaft seal housing and the engine block. There are specific points provided at the corners for prying the seal housing. Use care not to scratch the machined faces of the cylinder block, rear crankshaft seal housing or oil pan when scraping old gasket material from components. Thoroughly clean the mounting surfaces of the oil pan, rear crankshaft seal housing and engine block of old gasket material and sealer. Wipe the gasket surfaces clean with a rag soaked in brake system cleaner. Install the two dowels into the oil seal housing bolt holes (Alignment dowels installed in the rear crankshaft seal housing bolt holes). Apply a 1/8-inch wide bead of RTV sealant around the sealing area of the oil seal housing, passing on the inside of the bolt holes. Install the special alignment tool (EN47839) on the rear of the crankshaft, attaching it with the two supplied screws. Install the new oil seal housing over the alignment tool and studs onto the rear of the engine block. Remove the guide studs but leave the alignment tool in place. Install the housing bolts and tighten them to the torque. Remove the alignment tool. The remainder of installation is the reverse of removal. Add oil as necessary, run the engine and check for leaks.

Remove the crankshaft pulley. Note how the seal is installed-the new one must be installed to the same depth and facing the same way. Carefully pry the seal out of the cover. If you don't have a seal removal tool, thread a self tapping screw partially into the seal, then use pliers as a lever to pull it from the engine. If the seal is being replaced with the timing chain cover removed, support the cover on top of two blocks of wood and drive the seal out from the rear with a hammer and punch. Caution: Be careful not to scratch, gouge or distort the area that the seal fits into or a leak will develop. Installation: Apply clean engine oil or multi-purpose grease to the outer edge of the new seal, then install it in the cover with the lip (spring side) facing IN. Drive the seal into place with a seal driver or a large socket and a hammer. Make sure the seal enters the bore squarely and stop when the front face is at the proper depth. Note: Don't let oil get on the rubber part of the seal or on the part of the crankshaft pulley that touches the seal. The seal must be installed dry. Check the surface on the pulley hub that the seal rides on. If the surface has been grooved from long-time contact with the seal, the pulley should be replaced with a new one. Lubricate only the inside of the pulley hub with clean engine oil and install the crankshaft pulley. The remainder of installation is the reverse of removal.

Be careful not to scratch, gouge, or distort the area that the seal fits into, as it may cause a leak.

Don't let oil get on the rubber part of the seal or on the part of the crankshaft pulley that touches the seal. The seal must be installed dry.