Borg Warner — Velvet Drive Output Flange — 4-Inch Coarse 10-Spline — 4547BA
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Borg Warner Velvet Drive Output Flange — 4-Inch Coarse 10-Spline — 4547BA
The Borg Warner / Velvet Drive 4547BA is a 4-inch output flange coupling for applicable Velvet Drive 71C and 10-17 series marine transmissions. Its 10-tooth coarse spline connects the transmission output shaft to the propeller-shaft coupling, helping restore a secure driveline connection during transmission, seal, or shaft-alignment service.
Compatible Applications
- Velvet Drive 71C marine transmissions using the 4-inch, 10-tooth coarse-spline output configuration.
- Applicable Velvet Drive 10-17 and 1017 family transmissions with the matching output shaft and flange arrangement.
- Not a universal fit for every Velvet Drive 71 or 72 series transmission. Confirm the transmission model, output flange diameter, spline count, and existing coupling configuration in the applicable service documentation before ordering.
Part Details
- Brand: Borg Warner / Velvet Drive
- Part number: 4547BA
- Official product type: Marine transmission output flange / coupling
- System: Marine transmission and propeller-shaft driveline
- Flange diameter: 4.00 in / 101.6 mm
- Internal spline: 10-tooth coarse spline
- Configuration: Four-bolt output flange
- Alternate references: W4547BA, BW4547BA, Crusader R148014, and PCM R148014
Reference Dimensions
The following dimensions are published reference measurements for the equivalent Alto ALT23324 coupling:
- Hub dimension: 1.375 in / 34.9 mm
- Internal reference dimension: 1.184 in / 30.1 mm
- Overall reference dimension: 1.940 in / 49.3 mm
- Flange hub diameter: 2.325 in / 59.1 mm
- Bolt circle: 3.250 in / 82.6 mm
- Bolt-hole reference: approximately 0.390 in / 9.9 mm
Replacement and Related Parts
- Equivalent replacement reference: Alto 23324 / ALT23324
- Related rear output seal: 71C-110 / ALT23421
- Related coupling nut: 4775L / ALT23321
- A larger 5-inch coarse-spline coupling may be used on certain 72C configurations, but it is a different fitment and should not be substituted for this 4-inch flange.
Fitment and Installation
Before ordering, compare the existing flange diameter, spline count, transmission model, and output-shaft arrangement. When replacing the flange, inspect the output-shaft splines, retaining nut, rear output seal, coupling face, and bolt holes. Clean the flange and propeller-shaft coupling faces, install the retaining hardware according to the applicable Velvet Drive service procedure, and complete final shaft alignment.
When This Part Needs Replacement
- Worn or damaged internal splines
- Excessive movement between the flange and output shaft
- Corrosion or pitting at the rear seal contact surface
- A damaged or distorted coupling face
- Damaged bolt holes or flange hardware
- Persistent rear transmission oil leakage associated with a worn sealing surface
- Damage found during transmission removal or propeller-shaft alignment service
Technical FAQ
- Is 4547BA the 4-inch coarse-spline flange? Yes. The identifying configuration is a 4-inch flange with 10 internal coarse-spline teeth for applicable 71C and 10-17 applications.
- Will this fit every Velvet Drive 71 or 72 transmission? No. Similar transmissions can use different flange diameters, spline counts, or output-shaft arrangements. Verify the existing assembly before ordering.
- What is the aftermarket equivalent? Alto 23324, also referenced as ALT23324.
- What should be inspected during installation? Check the output-shaft splines, retaining nut, rear output seal, flange face, bolt holes, and final propeller-shaft alignment.
- Can the larger 5-inch 72C coupling be used instead? Not without confirming the complete transmission and driveline configuration. The larger coupling is a different fitment from this 4-inch 4547BA flange.
Parts Desk Insights
- Best use case: Replacing a worn or damaged 4-inch, 10-tooth coarse-spline output flange on an applicable Velvet Drive 71C or 10-17 transmission.
- Most common mistake: Matching the flange by diameter alone and overlooking the 10-tooth coarse spline or the transmission’s exact output configuration.
- Fitment guidance: Confirm the 4-inch diameter, 10-spline count, transmission model, and existing coupling arrangement before ordering, especially when working on a Velvet Drive 72 or reduction transmission.
Shipping information
In-stock and OEM parts: ship same or next business day.
Locally warehoused items: ship within 1-3 business days.
Special-order items: timeline confirmed after order.
Returns & warranty
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Important:
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