Photo 2/31 | 001 Ppe Duramax Engine Oil Pan | The factory stamped-steel lower oil pan is quite the sight to behold. Why engineers choose to place certain indentations in the places they do will forever be a mystery to us. We’re sure they have their reasons, however.
Photo 3/31 | 002 Ppe Duramax Engine Oil Pan | Since we had our LB7 Duramax out of the chassis for a rebuild, we decided this would be the best and easiest time to install PPE’s aluminum lower oil pan. Once the factory lower pan is detached, there are two studs in the upper pan that need to be removed. Since the studs are threaded into the upper pan, a pair of pliers made quick work of the job.
Photo 4/31 | 003 Ppe Duramax Engine Oil Pan | Located inside the lower oil pan is the low oil level sensor. The PPE pan has provisions for reusing the factory sensor. The first step in transferring the unit is to press the plug through the hole in the side of the pan. This plug seals with an O-ring and is held in place by a clip on the outside of the pan.
Photo 5/31 | 004 Ppe Duramax Engine Oil Pan | The sensor housing itself is bolted to a pedestal that is cast into the pan. Use caution not to overtighten these bolts.
Photo 6/31 | 005 Ppe Duramax Engine Oil Pan | The lower oil pan is sealed to the upper pan with a bead of silicon. We applied the same gray Clevite silicon we used to seal the rest of the engine’s critical surfaces, but any high-temperature sealant will work.
Photo 7/31 | 006 Ppe Duramax Engine Oil Pan | Once the silicon was applied, we carefully lowered the pan into place, ensuring the sealant wasn’t displaced in the process.
Photo 8/31 | 007 Ppe Duramax Engine Oil Pan | PPE replaces the factory bolts with Allen head fasteners. We started all the bolts by hand before tightening them mechanically. It’s worth noting that if you’re doing this install with the engine in the chassis, you’ll want to snug two or three of the bolts first to aid in holding the unit in place.
Photo 9/31 | 008 Ppe Duramax Engine Oil Pan | Extensions and a 3/8-inch-drive 6mm Allen socket are critical to ensuring the install goes smoothly. Without these tools, it will be somewhere between frustrating and impossible to properly tighten all the bolts.
Photo 10/31 | 009 Ppe Duramax Engine Oil Pan | PPE’s aluminum oil plan fits perfectly in the chassis of both two- and four-wheel-drive vehicles. The transmission fluid cooler lines are a tight fit, but they retain plenty of clearance. As mentioned previously, the pan can be installed with the engine in the chassis by removing the crossmember that spans below the pan (seen here).
Photo 11/31 | 010 Ppe Allison Transmission Deep Pan | The Allison 1000 transmission is fantastic by all accounts. However, its stamped pan leaves quite a bit to be desired. Fortunately, companies like PPE have addressed these with replacement cast-aluminum pans.
Photo 12/31 | 011 Ppe Allison Transmission Deep Pan | Before doing anything else, the transmission needs to be drained of its fluid. Fortunately, the Allison transmission has a drain plug—unfortunately, it’s recessed…more on that in a moment.
Photo 13/31 | 012 Ppe Allison Transmission Deep Pan | With the fluid drained, the 12 mounting bolts can be removed. As you get down to the last bolts, it’s critical to support the pan with a free hand, assistant, or transmission jack. The pan needs to be lowered straight down slowly.
Photo 14/31 | 013 Ppe Allison Transmission Deep Pan | And here’s why it’s critical to lower the pan slowly…despite draining the recessed plug, more than 2 quarts of fluid are left in the pan. If you’re not careful, these can end up coating your driveway or worse.
Photo 15/31 | 014 Ppe Allison Transmission Deep Pan | PPE offers a couple different versions of its Allison transmission pan; we opted for the deep variety that holds an additional 4 quarts of fluid than the factory version. Note the addition of cooling fins, temperature probe ports, and a flush-mounted drain plug on PPE’s version.
Photo 16/31 | 015 Ppe Allison Transmission Deep Pan | On the inside of the pan are a series of cast fins. These fins aid in heat dissipation, drawing heat to the cooling fins on the outside of the pan, and act as baffles as well.
Photo 17/31 | 016 Ppe Allison Transmission Deep Pan | Included with the pan is a new internal filter element. To remove the old filter, simply pull straight down. You’ll also want to ensure the orange O-ring is removed from the valvebody before installing the new filter. Beware, the filter and valvebody also contain fluid that is waiting to drench you and anything under it upon removal. You’ve been warned.
Photo 18/31 | 017 Ppe Allison Transmission Deep Pan | The Allison 1000’s pan gasket is a reusable steel and rubber unit. We gave ours a quick wash, inspected it for damage, and then reinstalled it on the new pan. You’ll want to use a bolt or two as guides to keep the filter in place while situating the new pan in the transmission.
Photo 19/31 | 018 Ppe Allison Transmission Deep Pan | Once all the bolts have been started by hand, they can be torqued to the required 15 ft-lb. You’ll need to use a crisscross tightening pattern to ensure even pressure on the gasket.
Photo 20/31 | 019 Ppe Allison Transmission Deep Pan | With the installation complete, it’s time to refill the transmission with fluid. We opted for Amsoil’s Signature Series fully synthetic automatic transmission fluid. Due to the pan’s increased capacity, we poured in nearly 14 quarts of fluid. Thankfully, Amsoil sells it in gallon jugs.
Photo 21/31 | 020 Ppe Allison Transmission Deep Pan | Functional bits aside, PPE’s deep transmission pan looks dead sexy as well.
Photo 22/31 | 021 Ppe 14 Bolt Differential Cover | Found under most ’01-and-newer Silverado 2500HD and 3500HD pickups, along with ’03-to-current Dodge/Ram 2500 and 3500s is the AAM11.5 full-floating rear axle. Known as the corporate 14-bolt in GM circles, this axle is incredibly stout, however, its Achilles heel is the stamped-steel cover.
Photo 23/31 | 022 Ppe 14 Bolt Differential Cover | Installation of PPE’s cast-aluminum cover begins easily enough with the removal of the 14 retaining bolts. Since these axles use a gasket instead of silicon to seal them, be ready with a catch pan, as fluid will begin seeping out immediately.
Photo 24/31 | 023 Ppe 14 Bolt Differential Cover | With all but two upper bolts removed, you can give the cover a little pry to slowly drain the fluid. This ensures a controlled release of the old fluid, instead of a sudden dump.
Photo 25/31 | 024 Ppe 14 Bolt Differential Cover | Now is a good time to give the rear axle gears a quick inspection. Look for abnormal wear marks, chipped teeth, or signs of water intrusion.
Photo 26/31 | 025 Ppe 14 Bolt Differential Cover | Once the old gasket is completely removed, the mating surface can be cleaned of any residual oil by wiping it with brake cleaner and a rag. We used a wire wheel to remove the old gasket, but any non-destructive method of your choosing can be used.
Photo 27/31 | 026 Ppe 14 Bolt Differential Cover | A new gasket is provided with the cover and needs to be installed with the writing facing up. Also seen here are the internal casting fins that help dissipate heat from the gear oil. The cover also comes with fill and drain plugs and two pre-tapped ports for temperature probes.
Photo 28/31 | 027 Ppe 14 Bolt Differential Cover | Before the new cover can be installed, the factory parking brake bracket needs to be trimmed. Following the diagram in the instructions, we placed the bracket in a vise and made the necessary cuts with an angle grinder.
Photo 29/31 | 028 Ppe 14 Bolt Differential Cover | After all the bolts were started by hand, we proceeded to torque them to the required 15 ft-lb in the crisscross pattern required. New Allen-head bolts are provided and a 3/8-inch-drive 6mm Allen socket is still your best friend.
Photo 30/31 | 029 Ppe 14 Bolt Differential Cover | PPE provides a nice big fill port on the front of the differential cover. While squeeze-bottle-type gear fluids would fill directly from the bottle, we needed to use a pump to top the differential off with the required 5 quarts of Amsoil Severe Gear 75W-90 fluid.
Photo 31/31 | 030 Ppe 14 Bolt Differential Cover | Aside from the improved appearance, the PPE heavy-duty rear differential cover provides added protection from impact, holds nearly 2 extra quarts of fluid, and helps keep that fluid cooler under heavy use.