What Dexter Fortress Threaded Aluminum Oil Cap do I Need for My 10k AL-KO Axles?
Updated 10/28/2025 | Published 03/16/2025
Question:
I have a 2005 Top Hat Industries gooseneck with 10k AL-KO axles. I am looking for a set of new oil caps for the axles. Do the Dexter Fortress Threaded Aluminum Oil Cap for 10K to 16K Axles fit my axles? I have had trouble finding a set that will seal due to the tappered inside of the hub.
asked by: Ethen K
Expert Reply:
Hello Ethen,
I am happy to make sure we get you the right cap. The Dexter Fortress Threaded Aluminum Oil Cap # DX59CR is made specifically for Dexter 10K to 16K axles, and while it might thread into your 2005 Top Hat's 10K AL-KO axles, it likely won’t seal properly. The issue comes down to the inside of the hub, Dexter hubs typically have a straight bore where the oil cap seals, but many AL-KO hubs from that era have a tapered seating surface inside. That taper can prevent the o-ring on the Dexter cap from making full contact, which means you could end up with leaks even if the cap seems to fit.
So while it might technically screw in, it’s not a guaranteed match due to that taper. The better route would be to look for an oil cap designed specifically for AL-KO 10K axles. Can you please respond back to the email with a picture of your axle tag so I can reach out to our friends at Dexter so we can find you the right fit?
(click to enlarge)
Product Page this Question was Asked From
Dexter Fortress Threaded Aluminum Oil Bath or Grease Cap for 10K to 16K General Duty Axles
- Trailer Bearings Races Seals Caps
- Caps
- Oil Cap
- 3.75 Inch O.D.
- 3.75 Inch
- 10000 lbs Axle
- 12000 lbs Axle
- 15000 lbs Axle
- 16000 lbs Axle
- Dexter
more information >
Featured Help Information
Instructions
Continue Researching
- Search Results: oil cap wrench
- Shop: Dexter Fortress Threaded Aluminum Oil Bath or Grease Cap for 10K to 16K General Duty Axles
- Shop: Camco Revolution RV Sewer Hose Extension w/ Swivel Bayonet and Lug Fittings - Brown - 10' Long
- Q&A: Will the Curt Replacement Lifting Nut part # C93NR Work for a Bulldog Jack?
- Shop: Valcrum Hydro-Shield Waterproof Aluminum Oil Bath or Grease Cap for 9K to 16K Axles
- Video: Review of Valcrum Trailer Bearings Races Seals Caps - Caps - VA35JR
- Search Results: trailer jack parts
- Search Results: bulldog trailer jack parts
- Search Results: trailer jack
- Shop: Valcrum Universal Threaded Aluminum Oil Bath or Grease Cap for 9K to 16K Axles - Black
- Shop: Valcrum Universal Threaded Aluminum Oil Bath or Grease Cap for 10K to 16K Axles - Gray
- Shop: Valcrum Universal Threaded Aluminum Oil Bath or Grease Cap for AL-KO 6K to 8K Axles - Black
- Shop: Dexter Fortress Threaded Aluminum Oil Bath or Grease Cap for Dexter 10K HD to 15K Axles
- Shop: RV Interior Lighting
- Search Results: rv interior lights
- Search Results: dexter hub cap
- Video: Review of etrailer Camper Jacks - Trailer Jack - TJD-12000SP-FIP
- Video: A Closer Look at the Gustafson Dinette Light with Inner Fabric Shade
- Video: Let’s Check Out the Dexter Fortress Threaded Aluminum Oil Cap for 9K to 10K Axles
- Q&A: Solution for Needing Replacement Oil Bath Cap 21-36
- Search Results: dexter oil cap
- Video: Review of Dexter Fortress Aluminum Threaded Cap Service Kit 9K To 10 K Dexter Axle - DX24HR
- Q&A: Trailer Hubs Leak Oil After Installing New Seal
- Video: Review of Gustafson Lighting RV Interior Lights - Ceiling Light Fixture - GUS58ZR
- Q&A: Rockwell 10k Trailer Axle Oil Cap
- Video: Valcrum Universal Threaded Aluminum Oil Bath or Grease Cap - Manufacturer Spotlight
- Shop: Gooseneck Hitch
- Q&A: Will the Dexter Fortress Threaded Aluminum Oil Cap Fit with an 8-Lug 15K Axle?
- Q&A: Recommended Aluminum Oil Cap Cover to Replace a Dexter 21-88
- Q&A: What Is The Correct Oil To Use In My Dexter Axles With Oil Lube Bath Hubs?
on Trailer Bearings Races Seals Caps
Kate F.
10/27/2025
Hey Ethen, were you able to track down an oil cap that seals properly on your AL-KO 10K axles? Knowing what ended up fitting could help others with the same tapered hub issue.