How to find the right Automotive Replacement Manual Constant Pinion Seals AI guide

Written by an AI model from its trained knowledge.

What the AI looks for in Automotive Replacement Manual Constant Pinion Seals

What the part is: Constant pinion is the older, mostly British, name for the input or clutch gear shaft. Its seal sits in the front bearing retainer behind the clutch. Many listings and catalogs file the same seal under 'input shaft seal', so search both terms with your gearbox code.
Exact dimensions: Match shaft diameter x housing bore x width exactly to the old seal or the OE part number. Older gearboxes often had running changes, and a seal that is close but not exact will leak or will not seat.
Lip design and direction: Match single or double lip, and any helix or directional marking, to the original. A directional hydrodynamic lip fitted to the wrong rotation pumps oil out instead of back in.
Shaft surface: Replace the seal only if the shaft journal has no wear groove you can feel. Otherwise fit a repair sleeve or a seal that rides on a slightly different track. A new lip on a grooved shaft leaks quickly, and the oil ends up contaminating the clutch.
Lip material: Use nitrile for standard gear oil. Use FKM (Viton) or polyacrylate if the original was, or if the gearbox runs hot. The wrong elastomer hardens or swells and fails early with some gear oils and temperatures.

Genuine OE / OE supplier: For classic or low-volume gearboxes, the OE part number is the most reliable way to match the seal.
National: A wide US catalog of shaft seals that can be cross-referenced by dimensions.
SKF (Chicago Rawhide): Large dimensional seal range, plus Speedi-Sleeve repair sleeves for grooved shafts.
Corteco: Freudenberg's aftermarket brand, strong on European and older vehicle applications.
Elring: Good coverage of European gearbox seals.

Functionally yes. It is the seal on the input (clutch) shaft at the front of the gearbox, so cross-check both category names using the gearbox code.