Extension Housing Gaskets Buying Guide — Cheap OEM Replacement Parts for Sale | REVXSC
Looking for cheap extension housing gaskets that won't fail in 6 months? Whether you're chasing ford 4r70w extension housing gasket leak, transmission tailshaft gasket replacement, how to replace extension housing gasket, best gasket for transmission extension housing, rtv vs gasket transmission tail housing, this guide covers what to buy, what to skip, and how to make sure the part you order actually fits your truck or car. Every extension housing gasket sold at REVXSC ships with a verified year/make/model/engine fitment table — no guessing.
What extension housing gaskets actually do
In one sentence: the thin gasket that seals the joint between the transmission main case and the rear extension housing to prevent fluid leaks. When they wear out, you'll typically feel it before you see it — your car starts telling you something is wrong, and ignoring it gets expensive.
Signs you need new extension housing gaskets
- transmission fluid leaking from the housing joint
- wet fluid film on the rear of the transmission
- drips on the driveway behind the engine
- fluid level dropping without visible front leak
- gasket visibly cracked or pinched on inspection
If you tick more than one box, replace before it leaves you on the side of the road. The repair gets a lot cheaper when you catch it early.
Also known as
Depending on the shop manual, region, or supplier you're reading, extension housing gaskets are also called: tail housing gasket, tailshaft gasket, rear extension gasket, extension housing seal, trans tail gasket. They all refer to the same component — when you're cross-referencing OEM and aftermarket part numbers, watch for these naming variations so you don't double-order the same item.
How much should you pay?
Online direct-ship from REVXSC undercuts dealer parts counters significantly. We carry quality replacement extension housing gaskets from Pioneer, Fel-Pro, Mahle, Victor Reinz, ATP, ACDelco, Mr. Gasket, Dorman — every listing shows the price, the fitment chart, and real product photos. No mystery part numbers.
Featured extension housing gaskets in stock right now
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OEM vs aftermarket: which to choose
For extension housing gaskets, the brand actually matters. Pioneer and Fel-Pro supply major automakers as OEM suppliers — when you buy their boxed retail product, you're getting the same engineering and tolerances. Choose paper or fiber gaskets for OE-style sealing or rubber-coated metal gaskets for higher-temperature and severe-duty applications..
Install: DIY or shop?
Difficulty: intermediate. Bay time runs about 90–240 minutes with the right tools. Lifespan you should expect: Replace any time the extension housing is removed.
How REVXSC keeps prices low
Every listing includes a year/make/model/engine table.
ACDelco, Bosch, Dorman, Dayco, FEL-PRO and more.
Ships from US warehouses with real tracking.
No knockoff boxes, no rebranded junk.
Extension Housing Gaskets shipping to every US state
REVXSC ships extension housing gaskets same-day from US fulfillment to every state. Whether you're chasing salt-corroded extension housing gaskets in the Midwest, heat-fatigued parts in the Southwest, or just need a fast OEM-grade replacement, every order ships from the US with tracking. We deliver to:
Common questions Americans ask about extension housing gaskets
How much does an extension housing gasket cost?
The gasket itself is cheap at $5-$20 from Pioneer, Fel-Pro, or Mahle. The expensive part is the labor since the driveshaft, crossmember, and sometimes the entire trans must come down. Shop bills typically run $200-$500.
Where is the extension housing gasket located?
It seals the joint between the main transmission case and the rear extension housing that the driveshaft slides into. You can see the seam clearly from underneath, usually right above the rear transmission crossmember.
What causes the extension housing gasket to leak?
Heat cycling, age, and overtightening all crack the gasket over time. A bent driveshaft or worn tailshaft bushing transferring side load into the housing also stresses the gasket beyond its design.
How long does it take to replace the extension housing gasket?
DIY plans 2-4 hours including dropping the driveshaft and supporting the transmission. Shop labor is typically 1.5-3 hours depending on access. Doing it with a fluid change and rear seal is the smart move.
Can I use RTV instead of a gasket on the extension housing?
Some shops do, but always check the service manual. Some Ford transmissions specifically call for a paper gasket and using RTV alone will leak. When in doubt, install the gasket the manufacturer specifies.
Do I need to drop the transmission to replace the gasket?
Usually not, but you do need to support the trans, remove the crossmember, drop the driveshaft, and unbolt the extension housing. On 4x4s the transfer case must come off first, which adds significant time.
Should I replace the tail seal and bushing while I am in there?
Absolutely. The labor is mostly the same and both parts are cheap. Bushings are typically the root cause of new seal leaks, so doing seal-bushing-gasket together is the proper service.
What torque spec for the extension housing bolts?
Most Ford 4R70W and similar units call for 25-35 ft-lbs in a cross pattern. Always check your service manual since over-torque crushes the gasket and under-torque leaves it weeping fluid.
Why is my transmission leaking after replacing the gasket?
Either the housing flange is warped, the bolts were not torqued evenly, or the leak is actually from the tail seal or pan and you misidentified it. Clean everything, recheck with dye, and confirm before opening it up again.
Top US searches for extension housing gaskets
Most-searched phrases from American shoppers comparing extension housing gaskets this year — all of these are served by what REVXSC stocks:
This guide is updated as our extension housing gaskets inventory and fitment data change. Last reviewed 2026-06-28.