Duo-Cone Floating Face Seal for Caterpillar D6 / 320 Excavator - Replaces 9W-6668 - Heavy Duty Mechanical Seal Group

Don't Let a $50 Seal Ruin a $10,000 Final Drive

Your final drive is leaking oil. You can see it pooling inside the sprocket and dripping down the track frame. Every hour the machine runs, the gears inside are starving for lubrication. If you don't fix this now, you're looking at a $10,000–$15,000 final drive rebuild.

The fix is this seal. It takes 2 hours to install and costs a fraction of what a dealer charges.

What Is a Duo-Cone Seal?

A Duo-Cone (or "floating face seal") is a precision mechanical seal used in tracked equipment final drives. It consists of:

• Two cast iron seal rings — precision-ground mating surfaces that create a metal-to-metal seal
• Two Toric O-ring energizers — rubber rings that press the metal faces together and allow the seal to "float" with shaft movement

The seal sits between the rotating hub and the stationary housing, keeping gear oil inside the final drive while keeping dirt and water out.

Symptoms of a Failed Duo-Cone Seal

• Oil visible on the inside of the sprocket or track frame
• Oil dripping from the final drive area
• Final drive running hot (due to low oil level)
• Grinding or whining noise from the final drive
• Track tension problems (contaminated oil in the track adjuster)

What's Included

• 2x Precision-ground cast iron seal rings (matched pair)
• 2x Toric rubber O-ring energizers
• Complete seal group — ready to install

Technical Specifications

• Cat Part Number: 9W-6668 (also cross-references 7M-0481)
• Type: Duo-Cone / Floating Mechanical Face Seal
• Material: Hardened cast iron rings, nitrile rubber energizers
• Condition: Brand New

Compatible Caterpillar Equipment

Excavators

• Cat 315 / 315B / 315C / 315D Excavator
• Cat 320 / 320B / 320C / 320D / 320E Excavator
• Cat 322 / 322B / 322C Excavator
• Cat 324D / 324E Excavator
• Cat 325 / 325B / 325C / 325D Excavator

Dozers

• Cat D5 / D5G / D5K Dozer
• Cat D6 / D6G / D6K / D6M / D6N / D6R / D6T Dozer

Loaders

• Cat 953 / 963 Track Loader
• Cat 939 Compact Track Loader

This is one of the most universal Cat final drive seals. Verify your parts manual lists 9W-6668 or 7M-0481 before ordering.

Why Buy From Trenchwell?

• Save 50%+ vs Dealer: Dealers charge $180–$320 for this seal. We sell it for $119.
• Complete Seal Group: You get both metal rings AND the rubber energizers. No separate orders needed.
• Protect Your Final Drive: A $119 seal protects a $10,000+ final drive. This is the cheapest insurance on your machine.
• Ships Fast: Lightweight item, ships quick in a padded envelope.

Installation Tips

Critical: The mating faces of the seal rings must be absolutely clean and coated with clean gear oil before assembly. Any dirt or scratches on the seal faces will cause an immediate leak. Handle the polished faces with clean gloves only.