If you want to add a little more strength to your rearend and get an added dose of style, then you'll want to check out a cap support rearend cover like the Perfect Launch cover we got from Proform Parts. These covers are designed to stiffen up the main cap area, helping gears to last longer and reduce the amount of ring deflection. The covers include two bolts to stabilize bearing main caps, fluid capacity and magnetic drain plugs, and mounting bolts, and they feature a black painted finish. Proform has them for the 10- and 12-bolt rears and they can be installed in just a few minutes with no special tools required. 1. Here is the 12-bolt version of the Perfect Launch cap support cover from Proform Parts and the other stuff required for installation. The cover is made of thick cast aluminum and coated in a satin black finish. The key feature of this cover is the two load bolts that thread through the cover and put pressure on each main cap, adding support and reducing ring gear and cap deflection. The cover comes with the mounting hardware, but you will need to get a tube of silicone and two quarts of axle fluid. 1. Here is the 12-bolt version of the Perfect Launch cap support cover from Proform Parts 2. Obviously, the old rear cover needs to be removed and the gasket surface and gear area cleaned thoroughly. A gasket scraper followed by some Scotch-Brite took care of the gasket surface. We used a few cans of brake cleaner and some rags to wash out all the old fluid. While we had access, we inspected the gears and Posi unit, which all checked out. We knew this car is equipped with some low rear gears, but we were able to get an exact ratio by counting the teeth on the ring (41) and pinion (9) and then dividing the ring number by the pinion. Ergo, 41 divided 9 is 4.55555556 or 4.56:1. 2. Obviously, the old rear cover needs to be removed and the gasket surface and gear area 3. Proform recommends using silicone in place of a gasket to limit cover deflection, so we laid down a bead on the cover. Before we put the cover up into place, we backed off the cap support bolts so they wouldn’t interfere with installation. The provided mounting hardware should be tightened to 25 lb-ft. It’s not shown in the photo, but we needed to get a longer bolt to go through the brake line distribution block. 3. Proform recommends using silicone in place of a gasket to limit cover deflection, so w 4. After the cover is tightened up, the bearing cap support bolts can be threaded in till they contact the caps. These do not need to be super tight—as a matter of fact, 10 lb-ft is all that’s required, so don’t get all macho or you could distort the bearing caps. Proform recommends adding a little silicone under the lock nuts before threading them on to prevent any fluid from seeping out from the threads. The lock nuts don’t need to be super tight either, so go easy. 4. After the cover is tightened up, the bearing cap support bolts can be threaded in till 5. The new cover has a filling hole and a drain plug for easy service in the future. The new fill hole is a bit higher than the factory one so make sure to pull the factory plug and fill the diff through the new fill hole till it runs out of the factory fill hole. We used Royal Purple’s 75-90 Max-Gear. This stuff combines synthetic oils with Royal Purple’s proprietary Synerlec additive technology. All viscosities of Max-Gear are formulated with hypoid friction modifiers necessary for use in clutch or cone-type differentials. No additional additives are necessary. 5. The new cover has a filling hole and a drain plug for easy service in the future. The 6. After all is said and down. SOURCES Royal Purple One Royal Purple Lane Porter TX 77365 888-382-6300 http://www.royalpurple.com Proform Parts Roseville MI 800-521-1005 www.proformparts.com By Calin Head Enjoyed this Post? Subscribe to our RSS Feed, or use your favorite social media to recommend us to friends and colleagues!