Baker Drivetrain Grudgebox Installation

ABOUT BAKER DRIVETRAIN GRUDGEBOX

INTRODUCTION

The GrudgeBox is an all spur 6-speed overdrive transmission that delivers uncompromised performance in all gears and significantly more torque capacity than the stock unit. The primary impetus for the design was performance, but the GrudgeBox was also designed for those who spend a lot of time in the saddle looking for that extra gear on the highway. 6^th gear is a true overdrive that is numerically mild to yield a 250 RPM drop as compared to the stock unit. The gearset fits into the stock transmission case with no modifications. It has earned its BAKER pedigree with extensive highway testing and many merciless passes at the dragstrip.

FITMENT

• 2006 – Later Dyna
• 2007 – Later Softail & Touring Models

BREAK-IN

The GrudgeBox requires no break-in schedule. However, we do recommend that you take it easy for the first 20 miles to confirm that there are no issues related to basic function of the transmission and the reassembly of the motorcycle. You will notice that the transmission will shift smoother and operate quieter after about 2500 miles. Like any machine, scheduled oil changes are key to years of trouble-free service. 

FLUIDS

WARRANTY

FEATURES AND GEAR RATIOS

FEATURES

1. 6-Speed overdrive design. The 5^th gear ratio of the GrudgeBox is 1:1 which is equivalent to the stock transmission 6^th gear ratio. The overdriven 6^th gear ratio offers a 250 RPM reduction for highway cruising.
2. Straight cut (spur) gears. Gear School 101. Helical gears are used in most motorcycles and cars these days because they are quieter than spur gears. However, there’s a cost for noise reduction because helical gears give up horsepower. The amount of horsepower given up is proportional to the angle of the helix on a given gear pair. The stock transmission has helical gears in 2^nd through 6^th. The GrudgeBox is configured with all spur gears and no sacrificed horsepower.
   
3. Gear width. Stock transmission gear engagement is typically .500”, GrudgeBox is .700” in 1^st through 4^th with nearly twice the circumferential tooth thickness. Generally speaking, torque capacity of a transmission is the product of the gearset center distance, gear engagement width, and circumferential tooth thickness at the pitch line.
4. Tapered roller main drive gear bearing. We replaced the problematic self-aligning stock main drive gear bearing with a tried-n-true opposing tapered roller bearing pair; patent pending. We did this because any transmission is only as strong as its weakest link.
5. Dog tooth engagement. The dog teeth on the stock 3^rd and 4^th gears have roughly .200” axial engagement with a less-than 1° undercut. This is a formula for gear hop-out. For the GrudgeBox we chose 4° undercuts with .250” axial engagement in all positions to guarantee NO gear hop-out or missed shifts, which translates into NO lost revenue if you are a Grudge hustler.
6. Direct acting shifter pawl. Upshifting with the stock 07-later shifter pawl is much like pushing on a rope. To make upshifts crisp and precise, we developed a direct acting pawl that engages the drum pins with negligible free play and no ropes.

GEAR RATIOS

Why Grudgebox?

GRUDGEBOX – BEHIND THE NAME

Grudge racing is street racing, often done illegally, in which real dollars are bet on a single race. As such, the internal configuration of the engine and drivetrain are a closely guarded secret to gain an advantage over the competitors. The GrudgeBox was conceived to be a high- performance transmission with performance inspired gear ratios but no outward appearance to give away the fact that a thoroughbred torque multiplying machine occupies the inner walls of the transmission case.

The GrudgeBox is available with different bearing door finishes: machined billet, chrome, polish, powdercoat with highlights, and Sleeper. The Sleeper door is available to achieve the aforementioned anonymity. To make the Sleeper door we apply mechanical taxidermy to a stock factory door by milling out all anatomy and bone structure on the stock door to leave a .125” thick shell with stock factory powdercoat. The shell then fits over a billet sub-door, like a 3D puzzle, to yield the Sleeper door which fathered the name GrudgeBox (figure 1). Externally, the GrudgeBox with the Sleeper door gives no indication that a drag racing transmission lives underneath and that may be the difference between winning and losing.

FIGURE 1 | GRUDGEBOX SLEEPER DOOR

REQUIRED PARTS, TOOLS, & REFERENCE MATERIALS

• Factory Service Manual for your year and model motorcycle
• Common hand tools (allen wrenches, sockets, retaining ring pliers, etc.)
• Breaker bar, 1/2" drive
• Torque wrenches, 3/8” & 1/2” drive
• 1-3/16” socket, 6 pt, 1/2” drive
• Red and blue threadlocker
• A new primary cover gasket
• Dial indicator (.0005” increments)
• MAP/Propane gas or heat gun
• Main drive gear & bearing service tool
• BAKER TOOLA-07
• H-D equivalent 35316C
• Inner primary race service tool
• BAKER TOOLB-56
• H-D equivalent 34902B
• Pulley locking tool
• BAKER TOOLC-56
• H-D equivalent 46282
• Pulley nut socket
• BAKER TOOLD-07
• H-D equivalent 47910
• Countershaft bearing service tool
• BAKER TOOLE-07
• Primary drive locking tool
• H-D-48219 (Touring models)
• H-D-47977 (Softail/Dyna)
• Primary fluid, 40 oz. (Touring models) or 46 oz. (Softail/Dyna)
• BAKER recommends Spectro Heavy Duty Primary Chain Case Oil; R.HDPCO
• Transmission fluid, 28-32 oz.
• BAKER recommends Spectro Heavy Duty Platinum 6 Speed Transmission Oil; BD-75140-32

HIGHLY RECOMMENDED ADDITIONAL PART

FIGURE 2 | BAKER ATTITUDE ADJUSTER

WHAT’S INCLUDED IN KIT?

BEARING DOOR EXPLODED VIEW

FIGURE 3 | EXPLODED VIEW, BEARING DOOR

BEARING DOOR PARTS LIST

GEARSET EXPLODED VIEW

FIGURE 4 | EXPLODED VIEW, GEARSET

GEARSET PARTS LIST

TAPERED BEARING EXPLODED VIEW AND PARTS LIST

FIGURE 5 | EXPLODED VIEW, TAPERED ROLLER BEARING

SHIFT SYSTEM EXPLODED VIEW AND PARTS LIST

FIGURE 6 | EXPLODED VIEW, SHIFT SYSTEM

BEFORE INSTALLING YOUR GRUDGEBOX

BEFORE YOU BEGIN

The transmission is a component in the powertrain of your motorcycle. As such, it’s function is highly dependent on other components in the powertrain to perform as designed. If the clutch, clutch actuator, primary, or shift linkage is worn, tired, or compromised in any way, the transmission will not perform as designed. The process of installing the GrudgeBox is the perfect time to assess and freshen up these components to ensure the transmission gives you years of trouble-free service.

TORQUE SPECIFICATIONS

STOCK COMPONENT REMOVAL

Refer to your Factory Service Manual for detailed instructions on how to remove your stock gearset, main drive gear, shifter pawl, and speed sensor from the transmission case. Softails, Dynas, and Touring models are all different configurations and require different methods to accomplish the removal. Ensure that you have the correct Factory Service Manual for your year and model of motorcycle.

BERT TIPS:

Apply heat to the comp sprocket bolt head prior to removal. Failure to do so could result in mangled sprocket shaft threads and halt the installation of your GrudgeBox. Remove the dipstick prior to removing the gearset from the transmission case. Failure to do so will result in a broken dipstick and a trip to the nearest H-D dealer.

TRANSMISSION CASE PREPARATION

Surgically clean the left side of the transmission case in preparation for installing the new GrudgeBox main drive gear and gearset. This surgical cleansing includes the main drive gear and countershaft bearing boss areas, the three inner primary mount bosses, and the shifter pawl boss. See figure 7.

The bearing boss areas must be clean to ensure that no dirt or debris scores the bearing bores during the removal of old bearings and installation of new ones. The three inner primary mount bosses need to be clean so that the tool plate registers flat on the left side transmission case.

FIGURE 7 | SURGICALLY CLEAN THE LEFT SIDE OF THE TRANSMISSION CASE IN THE AREAS INDICATED ABOVE

CAUTIONARY NOTE

There are special tools available from other manufacturers that remove and install the countershaft cup bearing, but they all have one fundamental error – they push on the inside of the cup (from right to left in the motorcycle) for removal and installation. THIS IS WRONG! Cup bearings require that the installation force be applied to the outside of the cup (from left to right). BAKER TOOLE-07 (sold separately) applies removal and installation forces in the proper direction.

INSTALLING THE TAPERED BEARING ADAPTER

TAPERED BEARING ADAPTER INSTALLATION

1. Apply a thin coating of oil to the outer diameter of the tapered bearing adapter. Do the same to the main drive gear bearing bore in the transmission case.	FIGURE 8 | TAPERED BEARING ADAPTER TOOL SETUP, RIGHT SIDE VIEW
2. Use the aluminum cup provided in your kit in combination with the main drive gear installation tool (BAKER TOOLA-07 or H-D equivalent 35316C) to install the tapered bearing adapter. Refer to the section on installing the main drive gear bearing in your Factory Service Manual. The tool will be set up in a similar manner, but with a few key differences. The tapered bearing adapter will take the place of the traditional main drive gear bearing, and the included aluminum cup will take the place of the bearing driver. See figures 8 and 9 for the proper tool setup.	FIGURE 9 | TAPERED BEARING ADAPTER TOOL SETUP, LEFT SIDE VIEW
3. Assemble the tool with the stepped down portion of the tapered bearing adapter facing toward the inside of the case; see figure 10. Make sure that the adapter is square to the bearing bore and snug the tool nut. If the adapter is not square to the bore, loosen the nut and realign the adapter. Leave the nut snug. Do not press the adapter into the case.	FIGURE 10 | TAPERED BEARING ADAPTER ORIENTATION IN CASE, TOP VIEW
4. The tapered bearing adapter has a tighter press fit into the transmission case than the stock bearing. To ensure successful installation of the tapered bearing adapter and longevity of the installation tool, you must heat the transmission case as shown in figure 11. Use a MAP/propane torch or a heat gun as shown in figure 12.	FIGURE 11 | APPLY HEAT AROUND THE MAIN DRIVE GEAR BEARING BOSS AREA
5. Apply heat evenly around the boss of the main drive gear bearing bore from the outside of the case as shown in figure 14. DO NOT heat the boss from the inside of the case and keep heat away from the tapered bearing adapter that is staged and ready for installation. The bearing bore boss should be heated to at least 200°F. BAKER recommends using an infrared thermometer to verify that the case is adequately heated; see figure 13.	FIGURE 12 | USE MAP/PROPANE GAS OR A HEAT GUN TO HEAT THE CASE
BERT TIP: You may see some discoloration where the case is heated. Restore color by rubbing a little bit of WD-40® or another thin oil into the powdercoat.	FIGURE 13 | USE AN INFRARED THERMOMETER TO VERIFY THAT THE CASE IS HEATED TO AT LEAST 200° F
6. Immediately after the case is heated, tighten the tool nut to draw the tapered bearing adapter into the case. This operation must be done quickly with no interruptions while the case is hot. If the support plate on the other side of the case starts to bend, stop, loosen the nut slightly, and reheat the case. The aluminum cup should be about flush with the bearing boss when the tapered bearing adapter is fully seated; see figure 14.	FIGURE 14 | TAPERED BEARING ADAPTER FULLY SEATED IN CASE
BERT TIP: Do not over tighten the nut after the tapered bearing adapter is bottomed out. Doing so may damage the tool or main drive gear bearing bore landing in the case. 7. Remove the installation tool. You will know the tapered bearing adapter is seated into the bore when the beveled retaining ring groove is fully visible; see figure 15.	FIGURE 15 | TAPERED BEARING ADAPTER VISUAL INSPECTION
8. Install the beveled retaining ring (VHO-334STPA) with the bevel facing outward. Make sure that the retaining ring fully seats into the groove; see figure 16.	FIGURE 16 | BEVELED RETAINING RING WITH BEVEL FACING OUTWARD

INSTALLING THE C/S BEARING & MAIN DRIVE GEAR

COUNTERSHAFT BEARING INSTALLATION

1. It is now time to install the new countershaft bearing that was provided in your kit. It is important that this step be done AFTER installing the tapered bearing adapter. This is to avoid cooking your new countershaft bearing while heating the case in that step.
2. Wipe out the countershaft bearing bore with a clean rag. Apply a thin coating of oil to both the bearing bore and the outer diameter of the countershaft bearing.
3. Use a countershaft bearing tool (BAKER TOOLE-07 or equivalent) to press the bearing into the transmission case. You want to press on the outside of the ‘cup’, just as you did during removal. See the appropriate tool instructions and your Factory Service Manual for details.

MAIN DRIVE GEAR INSTALLATION

1. Before installing the main drive gear, apply a thin coating of transmission oil to the tapered bearing races and the main drive gear O-ring; see figure 17. A thicker oil could give you a false reading when checking endplay.	FIGURE 17 | LIGHTLY OIL BEARING RACES BEFORE INSTALLING THE MAIN DRIVE GEAR
2. Each kit comes with four spacers for setting up end play in the tapered roller bearings: .102” (white), .104” (green), .106” (blue) and .108” (red) thick. The most commonly used spacer (.104”, green) is pre-installed on the main drive gear. The .102”, .106” and .108” spacers are included for cases where bearing end play is outside of the acceptable range with the pre-installed .104” spacer; see figure 18. Apply a thin coating of transmission oil to the main drive gear O-ring each time you change the spacer.	FIGURE 18 | MAIN DRIVE GEAR WITH PRE-INSTALLED SPACER AND TWO EXTRA SPACERS; LUBE O-RING
3. Follow the Factory Service Manual to install the main drive gear using BAKER TOOLA-07 or H-D equivalent 35316C. If the H-D equivalent tool is used, you will need to use pulley spacer 33334-GB from your kit for extra spacing while pressing the tapered bearings together. If you need to use the pulley spacer (33334-GB), temporarily remove the O-ring. Remember to re-install it after the end play is set. 4. Gently slide the assembled main drive gear through the case. Take the loose tapered roller bearing (HR32910J) and slide it over the main drive gear, letter side facing out. Slide the pulley spacer onto the gear if needed (O-ring groove facing bearing), followed by the remaining press tools; see figure 19.	FIGURE 19 | IF USING H-D TOOLING, THE PULLEY SPACER IS NEEDED TO EXTEND THE LENGTH OF THE INSTALLATION CUP
BERT TIP: Apply pressure to the main drive gear during this step by reaching your left hand through the top of the transmission case. Failure to do so (i.e. allowing the gear to flop around) will damage the bearing races. 5. With the tooling installed, snug the assembly by hand while making sure the installation tool cup is properly aligned and not skewed to the side of the tapered bearing. Hold the bolt on the inside of the case using the proper socket and ratchet. Tighten the main drive gear tooling on the primary side of the bike until it is fully seated and tight. Refer to the main drive gear tool instructions and figure 20.	FIGURE 20 | INSTALLING THE MAIN DRIVE GEAR
6. Do not remove the installation tool yet; leave everything tight. Measure the amount of end play in the main drive gear assembly using a dial indicator with .0005” increments as shown in figure 21. Total axial end play (pulling / pushing on the gear) must be between .0005” and .002”. It is extremely important that your bearing end play is within this range, as anything too tight or too loose may lead to transmission failure. Measuring end play is tricky. The end play measurement can easily be skewed if radial or rotational forces are applied, so try to keep all movement in the axial direction (parallel to the mainshaft). A correctly set up tapered roller bearing should be very tight. When your measurement is between .0005” – .002”, try spinning the main drive gear. If it spins freely with no drag and no excessive noise, setup is complete and you may proceed to the next step.	FIGURE 21 | CHECKING AXIAL END PLAY IN THE MAIN DRIVE GEAR TAPERED ROLLER BEARING Watch Class #4 on the BAKER Drivetrain YouTube channel for a video tutorial on setting up end play in the main drive gear bearing.

7. Remove the tooling used to install the main drive gear along with pulley spacer if you had to use it. If necessary, reinstall the O-ring (OR568M52) that you removed from the pulley spacer in step 3.
8. Put some transmission fluid on the outer diameter and O-ring of the pulley spacer. Install it onto the main drive gear with the O-ring facing inward (toward the bearing); see figure 22.	FIGURE 22 | INSTALLING THE PULLEY SPACER AND THE MAIN DRIVE GEAR SEAL
9. Put some transmission fluid on the lip of the main drive gear seal and install it. Make sure the seal is flush with the transmission case all the way around the bearing boss; see figure 23.	FIGURE 23 | MAIN DRIVE GEAR SEAL INSTALLED FLUSH WITH CASE

INSTALLING THE GEARSET

SHIFTER PAWL INSTALLATION
1. If you removed the stock centering pin to clean the case, reinstall it with red threadlocker. Install the GrudgeBox shifter pawl along with the new seal, washer, and 7/16” retaining ring just like a stock shifter pawl is installed. Do not remove the zip tie because it is placed on the pawl to keep the active plate retracted during gearset installation into the case; see figure 24.	FIGURE 24 | LEAVE THE ZIP TIE ON THE SHIFTER PAWL UNTIL AFTER THE GEARSET IS INSTALLED AND THE BOLTS ARE TORQUED
GEARSET INSTALLATION
2. The time has come to stuff the gearset (figure 25) into the transmission case. Before that is done, take time to ensure no debris or tarantulas have found their way into the case. Check that the two bearing door dowels came out of the case with old bearing door. Locate the new bearing door gasket onto the dowels of the GrudgeBox bearing door. Generously apply transmission lube to the last 6” of the mainshaft, end of the countershaft, countershaft bearing, tapered roller bearings, and the bearings/seal in the main drive gear. Do not remove the black rubber cap from the end of the mainshaft. Its function is to protect the seal in the main drive gear as the gearset is installed.	FIGURE 25 | GRUDGEBOX GEARSET READY FOR INSTALLATION INTO THE CASE
3. Carefully install the gearset into the transmission case. It is helpful to have a second set of hands on the left side of the motorcycle to grab onto the mainshaft as it passes through the main drive gear. The person on the left side can help the process along by gently rotating the main drive gear back and forth; this helps the 5th gear on the countershaft find home with the main drive gear. It is rare, but sometimes the fork rods need to be jostled to find home on the left side of the transmission case.	FIGURE 26 | TORQUE SEQUENCE FOR GRUDGEBOX BEARING DOOR BOLTS

FINISH LINE

WIRING DIAGRAM FOR IGNITION KILL SHIFT DRUMS