B25-270A 91005-RT4-005  25x89x13.5mm Automotive Bearings Ball Bearings

Product Overview

The B25-270A is a non-standard, single-row deep groove ball bearing with a 25 mm bore × 89 mm outside diameter × 13.5 mm width, identified through its OEM cross-reference Acura/Honda 91005-RT4-005 as an automatic transmission secondary shaft bearing. The bearing is produced from GCr15 chrome steel and is supplied open (no integral seals). Catalogue data consistently describes it as a ball bearing for the AT secondary shaft in 6-speed automatic transmissions (6AT) used across a range of Acura and Honda vehicles.

Critical application correction: automatic transmission secondary shaft, not a generic automotive bearing

The supplier form lists the application as the generic “Automotive bearings.” The OEM parts data is more specific and materially useful for buyers:

• Position: The bearing is listed under “AT SECONDARY SHAFT (6AT)” and “AT Secondary Shaft – Clutch (Low/2ND-5TH)” in Acura/Honda parts diagrams, confirming its role as the ball bearing supporting the secondary shaft within the 6-speed automatic transmission.

• OEM reference: 91005-RT4-005 is the Acura/Honda part number for the “Bearing, Ball (25X89X13.5)”, and this interchange is the most reliable way for buyers to confirm fitment.

• Vehicle fitment: The bearing is documented across 2010–2018 Acura MDX, RDX, RL, RLX, TL, and ZDX models equipped with the relevant 6AT transmission.

The Application field and the listing description should be corrected from a generic “automotive bearing” to “Automatic transmission secondary shaft bearing (6AT)” , with the Acura/Honda 91005-RT4-005 cross-reference added to the old-model or description field.

Structural and cage clarification

The supplier form classifies the bearing as a “Deep groove ball bearing” with a “Steel Cage.” The OEM data confirms the deep groove ball bearing classification (the part is explicitly named “Bearing, Ball”). However, the accessible OEM parts diagrams do not publish the cage material for this specific part number. The supplier’s steel cage specification should be verified against the physical stock rather than assumed; if the stock is a nylon-cage variant, the listing should reflect that.

Weight, load ratings, and speed limits: not published

No accessible public source publishes weight, Cr, C0r, grease speed, or oil speed for the B25-270A / 91005-RT4-005. The OEM parts diagrams provide dimensions, position, and vehicle fitment, but not standard bearing load ratings. These fields should remain blank or be marked “Consult supplier” rather than estimated from a generic 25 × 89 × 13.5 mm deep groove ball bearing, because the non-standard envelope and transmission-specific internal design make a generic estimate unreliable. This is consistent with the pattern across the preceding vehicle-specific bearing listings: OEM transmission bearings are specified by fitment and assembly position, not by published ISO load ratings.

Key Specifications

Performance Features

• Transmission-specific envelope: The 25 mm bore × 89 mm outside diameter × 13.5 mm width is sized to the secondary shaft mounting position in the 6AT transmission, where a standard 6205-series bearing would not provide the correct shoulder dimensions or axial spacing.

• Deep groove geometry: The single-row deep groove raceways carry radial loads and accommodate moderate axial loads in both directions, matching the combined load spectrum of a transmission shaft under gear mesh forces.

• GCr15 chrome steel construction: Rings and balls are through-hardened for rolling-contact fatigue resistance under the cyclic loading of automatic transmission service.

• Open configuration for ATF lubrication: No integral seals; the bearing is lubricated by the automatic transmission fluid (ATF) circuit, consistent with the wet-sump lubrication strategy of the gearbox.

• OEM interchange identification: The 91005-RT4-005 cross-reference allows buyers to confirm fitment against Acura/Honda parts catalogues for 2010–2018 MDX, RDX, RL, RLX, TL, and ZDX models.

Application

The B25-270A / 91005-RT4-005 is used as the ball bearing on the automatic transmission secondary shaft in 6-speed automatic transmissions (6AT) fitted to Acura and Honda vehicles. Published fitments include 2010–2018 Acura MDX, RDX, RL, RLX, TL, and ZDX. In service, the bearing supports the secondary shaft under the radial and moderate axial loads generated by the gear train, and it is lubricated by the transmission fluid. Replacement requires transmission disassembly and should follow the vehicle manufacturer’s procedure for bearing installation and shaft end-play adjustment.

Ordering & Logistics

• Stock: 105 pcs

• Minimum order: 1 pc

• FOB price: US$10 – US$50 per piece

• Payment: PayPal / Western Union / T/T (100% in advance)

• Delivery: 3–4 workdays after payment

• Shipping: DHL / FedEx / UPS / TNT

• Ports: Shanghai / Guangzhou

• Packing: Standard export packing

• Brand: As required (authorized brands only)

• Country of origin: China

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