BD Diesel Double Stack Cooler And Diesel Race Parts Allison Cooler Lines - Diesel World

BD Diesel Double Stack Cooler And Diesel Race Parts Allison Cooler Lines

Is your truck used primarily as a daily driver? Weekly towing workhorse? Or maybe a competition-only drag racer or sled puller? In any case, it’s certain that the automatic transmission used to transfer all of that horsepower and torque to the ground has undergone its fair share of abuse. Stop and go traffic, long steep mountain passes towing 15,000 lbs or hot, quick laps at the drag strip can all be extremely hard on a transmission and lead to hot fluid temperatures. In both stock and built transmissions, extreme fluid temperatures can lead to premature parts failure such as burnt clutches and fried torque converters, so keeping transmission fluid temperatures in a “safe zone” can pay dividends in the long run.

BD Diesel Double Stack Transmission Cooler

The newest transmission cooler system from BD Diesel of Abbottsford, British Columbia, Canada, should fill a large void in the performance diesel market, offering a completely universal system for both daily driver and weekend tow rigs, along with full competition-only drag and sled pull trucks. Using their already popular Xtruded core design from their air-to-air intercoolers, the Double Stack Xtrude transmission cooler comes complete with a 800-cfm electric fan, wiring harness, hoses, fittings and universal mount brackets. The unique stacked design allows for the use of two identical coolers to be mounted in a relatively compact system for maximum cooling surface in a minimum space. The electric fan kit is wired into the system to be triggered on/off as needed, based on transmission temperature, offering excellent cooling even at low speeds when consistent outside airflow across the coolers doesn’t exist.

1 The BD Diesel Xtruded Double Stack Transmission Cooler kit is a universal system capable of cooling transmission temperatures by up to 350% over stock, BD claims. The dual cooler design comes outfitted with a thermostatically controlled 800-cfm fan to keep air flowing over the cores, even at slow speeds or when the cooler is installed in a poor air circulation area of the vehicle like in the bed of a race truck or inside the frame rail.

2 Planning to install the Double Stack cooler on a 2002 Chevrolet Duramax already equipped with a built Allison transmission and large Titan replacement fuel tank, there was very little room under the truck inside the frame rails to position the cooler and fan assembly, so with some minor changes and the addition of the new high-flow replacement cooler lines from Alligator Performance, the cooler would soon find its home behind the grille directly in place of the OEM transmission cooler.

3 BD Diesel spent a lot of time developing a truly unique and universal transmission cooler system that could not only work well in a daily driver application, but with its stacked cores and universal brackets, make a great upgrade for competition-style trucks that don’t see much airflow across the coolers to keep hot fluid temps at bay. Vehicles such as dedicated drag trucks or sled pull trucks could benefit greatly from the monstrous cooler and electric fan.

4 BD Diesel offers their double stack cooler for both ½- and 5/8-inch cooler lines, and by using the supplied fittings and couplers, you can basically tee into your factory hard lines and loop fluid through the new Xtruded Cooler mounted in a position on the truck that makes the most sense for your specific application.

5 Since our truck was already in need of transmission cooler lines due to a couple of leaking joints on the factory lines, the BD Xtrude Cooler will be used in conjunction with the 5/8-inch performance cooler line kit manufactured by Diesel Race Parts, a division of Alligator Performance. The new DRP cooler lines use quality AN-style fittings and 2,325-psi burst-rated hose to ensure a leak-free perfect fit for the stock-style cooler, but thanks to the 5/8-inch fittings already found on the BD cooler, the DRP lines will thread right on, making for an extremely easy upgrade/install.

6 While in a basically stock application, the factory trans oil cooler can be sufficient. Once running at higher horsepower levels, the performance-built Allison transmission may see higher than stock fluid levels due to the higher torque multiplication of the triple-disc torque converter. On average, day driving would produce fluid temperatures around 110 degrees above ambient temps on the highway and as much as 140 degrees above ambient in stop and go city driving. It was nothing to see the built Allison run trans fluid temps of more than 230 degrees on the hottest July day.

7 After disconnecting the factory cooler lines from the bottom side of the stock cooler, it may be a good idea to cap the open ends of the cooler lines. Pulling the lines out of the truck is sure to be a complete mess and be prepared to be wearing at least a quart or two of lovely red trans oil all over yourself by the time you’re done. The capped lines will help keep fluid leakage and mess to a minimum.

8 With the cooler lines disconnected, it was just a matter of unbolting the factory cooler from its four mounting points. The new BD cooler is going to go directly in place of the stock cooler and use the factory holes and hardware, after some custom mounting brackets are fabbed up out of some ¾-inch strap steel.

9 On Duramax/Allison trucks, transmission fluid is run through a cooler housed inside the truck’s radiator. While avoiding extreme heat is always the biggest factor in a transmission’s lifespan, fluid that never warms up to safe operating temperatures can be hard on transmission parts as well, thus the fluid being run through the radiator. This system helps get the transmission fluid up to true operating temps quicker in cold winter mornings, but can also cause excessive heat buildup when coolant temps begin to rise in a heavy towing situation.

10 On the transmission side of things, the factory coolers use a unique push/pull lock-style connection that requires the removal of a metal C-style clip found under the plastic yellow collars. By popping the yellow collars off of the connection with a small pick tool, you’ll be able to see the metal clip that keeps the cooler lines tight within their fittings. The same pick tool can be used to remove the clip and then the cooler lines can simply be pulled straight out. Transmission fluid level should be below these fittings, but remember the lines will be full of fluid, so be prepared to spill some as you disconnect these lines.

11 Following the instructions supplied with the new DRP high-flow lines, we opted to cut the factory cooler lines with some hose cutters on the soft hose sections to make removing them easier. While we’ve heard the stock hard lines can be snaked out of the truck without cutting them, it seemed much simpler to just cut them and fish them out from each end.

The universal brackets supplied by BD allow endless mounting options to fit any vehicle’s specific requirements. While most will find the space needed under the truck inside the frame rails, the coolers could also be mounted inside the truck bed on drag race and sled pull applications. With more than 260 square inches of surface area and 40,000-btu/hr cooling capacity, the Double Stack cooler can offer up to a 350% temperature drop compared to a stock cooler, according to BD. BD claims their Micro Extruded bar technology offers efficient airflow across the core and turbulent oil flow inside, which offers the best cooling characteristics. The 5/8-inch inlet and outlet offers maximum flow with little restriction to fluid flow and ensure a leak-free connection tested to 300-psi of pressure.

Diesel Race Parts Allison Replacement Cooler Lines

Since the factory GM Allison transmission lines are prone to failure and leaking after racking up thousands of miles of on- and off-road abuse, Diesel Race Parts, an affiliation of Alligator Performance Diesel, developed their own resolution with a complete replacement performance hose kit. Using your choice of either ½- or 5/8-inch extremely heavy-duty 2,325-psi rated hose and the required fittings to connect your Allison to the factory cooler, leaks can be a thing of the past. Using quality AN-style fittings with O-ring and washer style junctions, once installed and secured, your stock or built Allison can keep moving your truck down the road worry free. DRP offers kits for both the 2001-05 and 2006-10 Duramax/Allison-equipped trucks, and while they’re designed to install directly to the stock fluid cooler, they can also be used with some aftermarket coolers depending on their mounting location and fitting sizes.

By running the larger high-volume 5/8-inch cooler line repair kit from DRP and mounting the new BD Diesel Double Stack cooler in the factory location (custom mount brackets had to be fabricated to do this) the two kits matched right up together and made for a relatively easy install that was completed in just one day out in the garage. It should be noted that, while the installation of the replacement cooler lines is fairly straightforward, be prepared to make a mess on the shop floor. Dropping a tarp under the truck may help, but with oil being trapped inside the factory cooler lines, when it comes time to remove the lines all together you may cause some fluid to be lost and spilled all over the place. Unfortunately, there just may be no way to get around the messiness of this job.

12 Since the BD Double Stack cooler is being placed directly behind the grille where airflow across the core won’t be an issue, the electric fan and shroud were removed from the coolers, which eliminated the need to do any wiring. But some new mounting brackets had to be fabricated out of some strap steel since the universal BD brackets were designed for under-truck or in-bed cooler mounting. On this particular truck, two 2-inch-long straps and two 5 ½-inch straps were made up to mount the cooler in the factory locations on the core support.

13 Once the mount brackets had been completed and the cooler was hard mounted in its final position, holding the factory cooler next to it you can plainly see the massive surface area increase for better fluid cooling. A quick measurement showed the OEM cooler at 50 square inches of surface area, while just one of the BD coolers had 130 square inches, which is doubled due to the stacked core design bringing total surface area up to 260 square inches.

14 The only real modification needed to fit the larger coolers and new lines was the removal of the center mount clip on the back side of the grille shell. The taller coolers would be directly in the way of this mount clip and the factory bracket that received the clip was removed when the stock cooler was tossed aside. The grille shell is just plastic, so it cuts easy and won’t really affect the structural fitment of the grille shell.

15 With our BD cooler fully installed, it was time to finish up our install by installing the new DRP AN-style fittings into the transmission and radiator. The new fittings are a high-quality fitting with 0-rings and washers on the mounting surfaces that ensure leak-free connections. You’ll notice two different style of 90-degree fittings for use on the transmission; this is done for clearance issues and helps make the install a bit easier.

16 After routing the DRP high-flow lines through the engine bay following the same path the factory lines took, they just needed to be threaded onto the fittings at the transmission end. Remember to use a wrench on both the hose end and the fitting to prevent any counter torque repositioning your fittings or stripping the threads in the aluminum case of the transmission.

17 The new lines were also routed right to their original location where they would’ve been threaded into the stock cooler, but since our BD cooler has the same 5/8-inch AN-style inlet/outlet as the new DRP lines, we were able to thread them right into place, making for an easy installation.

The 2002 Chevrolet truck that these two kits were being installed on had previously been upgraded with an Alligator Performance Stage 5 transmission kit (now with more than 30,000 trouble-free miles above 500 hp) so the high-volume 5/8-inch lines will offer the best flow and further increase the transmission and cooler’s performance. While the BD Double Stack system mounts easily under the truck inside the frame rails with a universal bracket system, the test truck had a larger than stock Titan replacement fuel tank that took up the space needed to install the new cooler, so it was decided that with some minor modifications, the Double Stack core would fit nicely behind the grille in the stock cooler’s location. Since this location offers great airflow across the core, the electric fan was removed before installation and some small metal brackets were fabricated out of some strap steel to hold the new cooler from the factory mounting holes.

Test Results

18 The last line installed was the shortest hose in the kit, which runs from the new BD cooler directly behind the grille to the topside of the radiator. This connection at the radiator needs to be handled with care as it can be easy to strip the radiator’s threads, and a large washer and double-stacked O-ring need to be used on the fittings to ensure a tight fit and leak-free seal. DRP includes picture instructions of this connection to be sure you get all the parts positioned correctly.

19 With the new Double Stack cooler and high-flow DRP cooler lines fully installed, the grille shell, intercooler pipe and intake system were reinstalled. It’s vital that the fluid level be checked and filled as needed before the truck is taken out for a drive. Remember the removal of the stock cooler and lines would’ve caused the system to lose a small amount of fluid and it’s going to need to be replaced, along with some additional fluid to fill the additional capacity of the larger coolers. After a full week’s worth of city and highway driving, our test truck has experienced more than a 60-degree drop in fluid temperatures. This should be even more substantial in a towing situation when there’s a much larger load on the engine, transmission and drivetrain.

Before installing the new Double Stack cooler kit and DRP cooler lines, data was recorded so a true before and after temperature comparison could show just how much improvement the system upgrades would have. Under normal day to day city and highway driving, the test vehicle’s transmission fluid had been running around 110 degrees above the outside air temperature and had seen as much as a 145-degrees over ambient. So during the hot summer months at 100 degrees, it was nothing to see transmission fluid run in the 208 to 230-degree range, and this was in normal city driving, not towing. After installing the new BD cooler system and replacing the leaking factory cooler lines with the high-flow lines from DRP, fluid temperatures have dropped an average of 60 degrees, where a much more manageable 150-160 degree fluid temperature is common during daily driving. The extreme abuse of heavy towing has also shown a substantial drop in fluid temperatures, where while even traveling slow up slick mud/snow roads during hunting season, the Allison kept under 200 degrees with 14,000 lbs behind the truck. Cool enough! DW


BD Diesel

Alligator Performance