Mavnai Transmission Oil Pan Gasket for GM 4L60E & 700R4 — 3/16" Thick, Steel Shim, 70A Vulcanized Rubber

This gasket is engineered as an upgraded alternative to cork and conventional rubber gaskets, designed to meet or exceed OE specifications and to replace Moroso 93104. Built around a 0.8mm galvanized hardened steel core and vulcanized twice to a rigid frame, it resists warping, holds bolt threads securely during installation, and provides a longer service life compared with single-material gaskets.

How does the steel shim improve gasket performance?

The internal steel shim stabilizes the gasket body, keeping the sealing surface flat under load and heat cycles. That metal core prevents the gasket from stretching or deforming, which reduces leaks that commonly develop in softer materials over time.

• 0.8mm galvanized cold-hardened steel shim for rigidity
• Prevents warping and uneven compression
• Maintains bolt hole alignment during installation

What makes the vulcanized rubber better than cork or standard rubber?

This gasket uses industrial-grade oil-resistant rubber vulcanized to a steel frame at 70 durometer hardness, giving it a balance of resilience and firmness. The double vulcanization process bonds the rubber to the metal so the gasket resists oil soak, shrinking, and brittle failure much longer than typical cork or soft rubber parts.

• 70 durometer rubber resists oil and temperature breakdown
• Double vulcanization ensures durable metal-to-rubber bonding
• Thicker 3/16" cross-section for improved sealing surface

Is installation straightforward and does it require sealant?

Installation is simplified by the gasket's rigidity: bolt holes stay aligned and the part holds its shape while you work, which speeds up fitting. Because it is designed for smooth, flat mating surfaces, no sealant is required; however, you must ensure the pan and transmission flange are clean and flat to achieve a reliable seal.

• No adhesive or RTV needed on clean, flat surfaces
• Rigid frame keeps bolt holes aligned for faster installation
• Not recommended for pans with raised ridges on mating faces

How durable is this gasket over time and repeated service?

Constructed to be reusable and resistant to cracking, this gasket is less likely to fail under routine service intervals than monomaterial designs. Its thicker profile and reinforced structure give it a higher lifetime value, reducing the need for frequent replacements and lowering long-term maintenance costs.

• Full 3/16" thickness reduces risk of cracking
• Designed for multiple service cycles when properly handled
• Manufactured and tested by an experienced gasket factory

Who is this for: This gasket is aimed at professional mechanics, DIY enthusiasts, and restoration shops working on GM transmissions that use the 4L60E or 700R4 pattern, or anyone replacing a worn Moroso 93104-style gasket. Choose this part if you want a durable, rigid gasket that simplifies alignment during installation, improves long-term sealing performance, and offers better resistance to oil and heat than cork or soft rubber options. If your transmission pan has a raised mating ridge, verify compatibility first; otherwise, prepare flat, clean mating surfaces and install without additional sealant for best results.