Clutch Player: Dual Disc Clutch

Installing a South Bend Dual Disc Clutch in a 2006 Dodge Work Truck

Many diesel owners like to shift their own gears, especially those that depend on their trucks for hauling heavy loads. One such person is Roy Dorn: he’s a general contractor from Sale Creek, Tennessee, and he relies on his 2006 Dodge 3500 4WD truck to transport tools and materials to the homes he builds and remodels in southeastern Tennessee. With the loads he tackles on a regular basis, the factory single disc clutch, dual mass flywheel and basic hydraulics were definitely the weak link in his otherwise strong, 205,000-mile Dodge.

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Since upgrading to EFILive, tuning and improving the airflow with an AEM intake system (see the June 2015 issue of Diesel World for the details), Dorn knew that he would be pushing the limits of the factory clutch. Rather than waiting for the clutch to burn up, he wanted to be pro-active and replace it with an upgraded clutch that would easily handle any loads. So he contacted the experts at Beans Diesel Performance, who suggested replacing the factory setup with a South Bend Clutch SDD3250-GK Street Series dual disc clutch kit, capable of handling between 550-650 horsepower and up to 1,400 lbs-ft of torque. The kit comes with a new single mass flywheel, dual-friction clutch discs, 3,250-pound diaphragm style pressure plate, clutch fork, throw out bearing, installation hardware and upgraded hydraulics.

INSTALLATION

We took Dorn’s truck up to Bean’s Diesel Performance in Woodbury, Tennessee, to install the South Bend clutch kit. BDP technician Marty Meraz handled the installation in about eight-and-a-half hours. An experienced DIYer—with the proper tools and equipment—could complete the clutch upgrade in a full day,
either in a garage or on a flat driveway, but working on the ground will make the job a lot more difficult. Fortunately, the team at Bean’s has multiple truck lifts. DW

1 Marty Meraz started by removing the shifter console and 4WD selector lever before removing the G56 shift lever. Notice the leaked transmission fluid from the torn shift boot: we’ll address an inexpensive replacement boot later.

2 After lifting the truck into the air, Meraz drained the old fluid from the transfer case to keep it from spilling during the clutch swap.

3 Then, he unbolted the rear drive shaft from the rear axle and carrier-bearing mount before removing the drive shaft.

4 On the front side of the transfer case, Meraz unbolted the front drive shaft and secured it to the frame with a bungee cord; then he removed the linkage from the transfer case.

5 The slave cylinder was easy to unbolt and remove from the driver side of the G56 transmission.

6 Before removing the transmission crossmember, Meraz supported the weight of the transmission and transfer case with a muffler jack. Then, he removed the crossmember and secured the transmission assembly with a transmission jack, running a ratchet strap around the transmission to prevent it from moving around.

7 With the transmission secure, Meraz removed the bell housing bolts with an impact gun and the long extension with a wobble-socket to allow him to work at an angle and reach all of the mounting bolts. Then, the transmission assembly could be moved back to disengage the input shaft from the clutch and then lowered out of the way.

8 When he removed the pressure plate, Meraz noticed that there was some fairly significant heat build-up evident on the flywheel and pressure plate.

9 The factory dual-mass flywheel bolts to an intermediate flex plate with eight bolts. These bolts can only be reached through the access port on the front side of the motor plate using a baring tool to rotate the engine. Once all eight were unbolted, he removed the flywheel.

10 The flex plate had to be removed from the crankshaft to install the new single-mass South Bend Clutch flywheel.

11 When he removed the flex plate, he found an oily mess thanks to a leaking rear main seal.

12 Rather than removing the seal from the housing (see arrow) with a screw or pick tool, Meraz and the crew at BDP recommended removing the housing and changing its seal, then reinstalling it with a new gasket to avoid the possibility of damaging the crankshaft.

13 After the seal was replaced, Meraz installed a new camshaft seal O-ring in the motor plate and reinstalled it on the engine.

14 Then, he installed the new flywheel using red thread locking compound on the mounting bolts and torqueing them to 100 ft-lbs as directed in the SBC installation manual.

15 Next, he used the supplied clutch alignment tool to position the clutch discs and intermediate plate before installing the pressure plate and torqueing those mounting bolts to 45 ft-lbs.

16 Meraz then turned his attention to the transmission, where he removed the old shift fork and flywheel. Before installing the new SBC replacement parts, he removed the spacer from behind the pivot ball and cleaned the inside of the bell housing with brake cleaner. Then, he installed the new throw-out bearing and shift fork in the bell housing.

17 The next step was for Meraz to reinstall the transmission: he moved it into position and then lifted it with the transmission jack and aligned the input shaft with the pilot bearing in the flywheel and the clutch discs.

18 Do not try to suck the transmission up to the engine with the bolts, as you could damage the case if the input shaft is not properly aligned. Meraz made sure the transmission was fully seated against the motor plate, and then installed the mounting bolts and hand threaded them into the motor plate before tightening them with an impact gun.

19 Meraz then reinstalled the transmission crossmember and then both drive shafts using red thread locking compound on the bolts. The transfer case was then refilled with Schaeffer’s Supreme All Trans synthetic transmission fluid, which is recommended by BDP for long life lubrication.

20 After lowering the truck, Meraz crawled under the dash to disconnect and unbolt the clutch master cylinder from the pedal and firewall. Then, he was able to pull the old hydraulic assembly out of the engine bay.

21 Looking at the old-versus-new clutch hydraulics, it is easy to see the larger diameter SBC cylinders as well as the stainless braided hose and heat shielding.

22 Meraz fed the new clutch slave cylinder down to the transmission before mounting the master cylinder to the firewall and connecting the piston to the clutch pedal.

23The SBC remote clutch reservoir can be mounted directly to the firewall above the master cylinder with the included sheet metal screws.

24 Climbing under the truck one more time, Meraz installed the slave cylinder on the transmission in the same way the old slave mounted.

25 Be sure to secure the clutch line safely away from any moving parts.

26 Meraz used a Doorman CV boot to replace the torn and leaking factory boot on the shifter—a cost-saving successor to the original Dodge boot. He secured it to the housing and shift lever with zip ties.

27 After applying a bead of sealant to the shift housing, Meraz reinstalled it in the top of the transmission.

28 Then, he finished up the process by installing the shift levers and console pieces.

Most people would expect that the heavy pressure plate and dual disc clutch capable of handling up to 650 horsepower and 1,400 lbs-ft of torque would be a pain in the leg to drive. That’s not the case with the SDD3250 Street Series clutch from South Bend Clutch. Thanks to the improved hydraulics, it offers nearly the same feel as the factory clutch, but with much better holding power. While it’s not recommended for competitive use, it’s a great clutch for manual transmission owners with performance upgrades that are making more power, as well as those who like to use the full capability of their trucks and tow heavy loads on a regular basis. If your G56 still sports the factory clutch, you owe it to your truck to check out the offerings from South Bend Clutch.

SOURCES
Beans Diesel
Performance
615.563.7800
www.bdpshop.com

Schaeffer’s
Specialized Lubricants
800.325.9962
www.schaefferoil.com

South Bend Clutch
800.988.4345
www.southbendclutch.com