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BAKER Direct Drive 6-Speed |
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RPM Reduction compared to stock 5-speed with a 25/36 Front and 32/70 Rear - 363rpm |
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Warranty - 5 Year/50,000 Mile
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Case Modification for Installation
 Generally, no modification is required. The DD6 was designed to fit both stock and aftermarket cases. That being said the DD6 instruction book suggests the following as a precaution. "The internal walls of cases 'float around' occasionally in H-D and aftermarket castings, this is not an indication of poor quality, but rather, is inherent of the casting process." The instruction guide then suggests the installer checks for any potential interference points removing them with a die grinder if necessary.  Once clearance checks have been made and the gear set is able to rotate unimpeded inside the transmission housing you can proceed with the remaining steps outlined in the installation manual.
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Additional Parts Required
If you're installing the DD6 kit on a bike with electronic speedometer you will need a speedo reclibration box. The BAKER recalibration box (PN 95E-56A seen here) retails for $135.00 and features a push button system that dials in your speedometer and keeps it calibrated for an accurate reading every time.  Additionally, FLH/FLT models will require the use of the BAKER Oil Spout Spacer Kit when reusing the stock oil spout PN 62419-93 (sliver) or 62429-93 (wrinkle black) The BAKER Oil Spout Spacer (PN 109-56) retails for $29.00 |
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Side Cover Compatibility
Compatible with all stock and aftermarket side covers.
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Gears
The DD6 is silent in 4th through 6th and strong in 1st through 3rd. The BAKER DD6 gearset was designed with spur cut 1st - 3rd gears and helical cut 4th - 6th gears. Spur cut gears were selected in 1st, 2nd and 3rd for added strength in the torque ranges while helical cut gears were used in 4th, 5th and 6th for noise reduction.  Unlike spur cut, helical gears have inherent noise reduction characteristics. The helical gears yield a contact ratio of 2.5, as compared to 1.8 for a spur gear. Higher contact ratio means more of the gear teeth are in mesh with less resultant chatter and noise. 1 degree dogs with lead in chamfers were utilized to increase shiftability. |
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Gear Ratios
Overall - 10.60 or 9.69 (1st)*, 7.19 (2nd), 5.25 (3rd), 4.05 (4th), 3.23 (5th), 2.81 (6th)
*1st gear is a no cost option
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Shift System
The shift system that comes with the DD6 kit utilizes a 'fixed spindle' radial ball bearing mounted shift drum.  The fixed spindle drum design eliminates any chance of binding or imposed friction about the axis of drum rotation. The fixed spindle drum system combines with three hard chrome plated shift forks and a newly designed 'anti-overshift' ratchet pawl to achieve a superior shifting transmission. To aide the rider in finding neutral a redundant neutral detent was added. |
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Bearing Door
3 door options are available with the DD6 including Chrome, Polished and Wrinkle Black. The bearing door is the same width as stock and therefore does not cause any fitment issues when used with stock exhaust pipes. Unlike the Screamin Eagle transmission, the speedo sensor remains in the stock location in the transmission case and not on the bearing door. The BAKER DD6 bearing door is also compatible with all stock and aftermarket side covers. |
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Additional Notes
The DD6 has superior shift quality. With its direct drive technology, 6th gear is 1:1. In order to achieve rpm reduction vs. the stock 5-speed the primary is overdriven with a 28 tooth compensating sprocket. Why achieve the rpm reduction this way? By making 6th gear 1:1 and overdriving the primary there is less parasitic power loss making the DD6 99% efficient in 6th gear. The picture below illustrates this point.
BAKER Direct Drive 6-Speed Powerflow
99% Efficient
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RPM Reduction compared to stock 5-speed with a 25/36 Front and 32/70 Rear - 390rpm |
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Warranty - 1 year (If Installed By HD Dealer) |
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Case Modification for Installation
Irreversible case modification is required with drilling and die grinder work. Removal of the right side fork rod boss is necessary in order to install the Screamin' Eagle gear cluster. The kit provides you with a template or 'drill plate' that mounts to the bearing door flange with two socket head cap screws as seen in the picture above. There is a special note in the instructions that states the following in regards to the installation of the drill plate. "Be sure drill plate is properly oriented. Improper orientation will result in damage that requires replacement of the transmission case."  Removal of the fork rod boss is to be completed as follows... "Starting with a 3/8-inch drill bit, alternately use progressively larger bits to enlarge the fork shaft hole. Finish the drilling operation with a 3/4-inch drill bit. Remove all remaining material up to the edge of the drill plate with a die grinder or a similar tool. Remove the drill plate." *Note* Once the right side fork rod boss has been removed, converting back to a 5-speed is impossible without the purchase of a new transmission case. |
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Additional Parts Required
The Screamin Eagle 6-Speed requires the use of either the Mechanical SE side cover (PN 38752-04) which retails for $199.95  or the Hydraulic SE side cover (PN 38753-04A) which retails for $299.95. *Note* The hydraulic side cover release kit is not compatible with 1990-98 touring models.
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Side Cover Compatibility
Only compatible with Screamin Eagle side covers. Not compatible with stock or any other aftermarket side covers. |
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Gears
Reports of noisy 4th and 6th gears are common, particularly when the transmission / engine is warmed up. This is due to the inherent noise characteristics of the spur gear design.The Screamin Eagle 6-Speed utilizes spur cut gears in 1st through 6th.
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Gear Ratios
Overall - 10.11 (1st), 6.96 (2nd), 4.95 (3rd), 3.87 (4th), 3.15 (5th), 2.80 (6th)
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Shift System
The Screamin Eagle 6-Speed utilizes a  Cast drum with roller detent and live spindle. The pillow blocks rotate around the drum on needle bearings. The shift system combines with three cast shifter forks and the late model shifter pawl (PN 35146-03).
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Bearing Door
The Screamin' Eagle bearing door comes in chrome finish and maintains the overall stock width of the transmission in combiniation with the SE side cover. The speedo sensor has been added to the top face of the bearing door as apose to the stock location on the transmission case. The SE side cover is the only side cover that will work with this bearing door.
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Additional Notes
The Screamin' Eagle 6-Speed has good shift quality overall. Since it is a true overdrive design the gearset is around 92% efficient so expect some power loss. With all 6 gear pairs being spur cut the rider should expect a certain level of noise especially in Twin Cam applications while in 4th or 6th gear.
Conventional Overdrive Powerflow
92% Efficient
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