Genuine Moroso 93104 Specifications for Reference
The genuine Moroso 93104 is part of Moroso’s Perm-Align transmission-gasket family.
Moroso manufactures its genuine 93104 from:
40-durometer rubber vulcanized to a rigid steel frame
Moroso specifies:
Thickness: 3/16 inch
Quantity: One per package
and states that the gasket:
Requires no sealant
Moroso designs the rigid construction for easier pan removal and reinstallation during transmission maintenance.
Those are specifications for the genuine Moroso product.
Do not automatically attribute Moroso’s exact material specifications to this aftermarket replacement.
Steel-Reinforced Construction
According to the supplied manufacturer information, this replacement uses a:
Steel shim core
laminated with:
High-durometer vulcanized rubber
The steel reinforcement helps the gasket maintain its shape instead of folding, stretching or sagging while the transmission pan is being positioned.
That can make installation considerably easier, particularly when working underneath the vehicle.
The rigid structure also helps keep the bolt holes aligned with the pan and transmission case.
Full 3/16-Inch Thickness
The supplied specification lists:
3/16-inch gasket thickness
That matches the thickness Moroso publishes for its genuine 93104 Perm-Align gasket.
The thicker reinforced construction is designed to provide consistent sealing while resisting the distortion that can affect softer cork and composite gaskets.
Thickness, however, cannot compensate for a severely warped transmission pan.
Both mating surfaces still need to be clean and flat.
Why Transmission Pan Gaskets Leak
A leaking transmission pan doesn’t automatically mean the gasket itself failed.
Common causes include:
- Warped pan rail
- Raised bolt holes
- Overtightened bolts
- Loose fasteners
- Uneven gasket compression
- Dirty sealing surfaces
- Old gasket material
- Excessive RTV
- Damaged transmission case
- Incorrect gasket
- Leak originating somewhere above the pan
Before replacing the gasket, clean the transmission and determine where the fluid is actually escaping.
Automatic transmission fluid can travel along the case and make another leak look like a pan-gasket failure.
Check for Leaks Above the Pan
Potential leak sources on GM automatic transmissions can include:
- Cooler-line fittings
- Electrical connector
- Selector shaft
- Dipstick tube seal
- Servo area
- Output seal
- Input/front pump area
- Vent
- Case fittings
Identify the highest point where fresh fluid appears.
Otherwise, it’s entirely possible to install a beautiful new pan gasket underneath a transmission that continues leaking from somewhere else.
Clean, Flat Surfaces Matter
The supplied manufacturer instructions correctly emphasize using:
Clean and flat mating surfaces
Before installing the gasket, inspect both:
Transmission-case sealing rail
and
Transmission-pan rail
Remove:
- Old gasket material
- RTV
- Oil residue
- Dirt
- Corrosion
- Burrs
The sealing surface should be smooth enough to compress the gasket uniformly.
Check the Pan for Warpage
Stamped-steel transmission pans are particularly vulnerable to distortion from overtightened bolts.
The metal around each bolt hole can become pulled upward.
That creates high spots around the fasteners and low spots between them.
The result can be:
Heavy gasket compression around the bolts
but
Insufficient gasket compression between the bolts
Place the pan on a known flat surface or inspect its rail with an appropriate straightedge.
Correct minor deformation appropriately or replace a badly damaged pan.
No Sealant With Genuine Moroso Perm-Align
Moroso specifically states that its genuine Perm-Align gaskets:
Require no sealant.
Moroso also warns that loose pieces of sealant can enter a transmission and potentially obstruct internal passages or transbrake components.
For this aftermarket replacement, follow its actual manufacturer’s instructions.
If it is also designed for dry installation, don’t add RTV simply because the tube is already open.
A reinforced gasket works by controlled compression.
It doesn’t need to be buried under silicone unless the gasket manufacturer specifically calls for it.
Easy Bolt-Hole Alignment
One of the practical advantages of a steel-reinforced gasket is installation stability.
A conventional flexible gasket can shift while you’re trying to simultaneously hold:
- Transmission pan
- Gasket
- Fasteners
- Your patience
The rigid internal structure keeps the gasket profile stable and helps the bolt holes remain aligned.
That makes starting all the pan bolts easier.
Start Every Bolt by Hand
Once the gasket and pan are positioned, start every fastener by hand.
Do not fully tighten one corner first.
The goal is to establish:
Pan alignment
Gasket alignment
and
Even initial compression
before final torque.
This also reduces the risk of cross-threading a transmission-case bolt hole.
Tighten the Pan Progressively
Moroso’s current Perm-Align installation procedure for its genuine 93104 calls for progressive tightening.
Moroso specifies:
First pass: Hand-tight until the gasket is mildly compressed
Second pass: 60 in-lb
Final pass: 120 in-lb
Then repeat the final sequence to verify even torque.
120 in-lb = 10 ft-lb
Those are Moroso instructions for the genuine Perm-Align system.
If this aftermarket gasket or the transmission pan manufacturer specifies another procedure, follow the instructions supplied with the actual parts.
Don’t Overtighten the Pan
Transmission-pan bolts do not need heroic torque.
Overtightening can:
- Distort a stamped pan
- Crush the gasket
- Damage transmission-case threads
- Create uneven sealing pressure
- Pull bolt holes upward
- Cause future leaks
A torque wrench is a much better tool than tightening every fastener until your wrist announces that it’s probably enough.
Genuine Moroso 42025 Transmission Pan
A natural performance upgrade for this transmission family is the Moroso 42025 GM 700R4 Transmission Pan.
Moroso builds the 42025 from fabricated aluminum and uses a:
One-piece billet rail
that is:
CNC-machined after welding
for improved flatness.
The pan is 2.375 inches deep and includes:
- Magnetic -8AN drain plug
- 1/4-inch NPT port
- Serrated flange hex bolts
Moroso specifically pairs:
42025 Pan
with
93104 Gasket
for the compatible 700R4 / 4L60-family application.
Why a Billet Pan Rail Helps
A rigid billet pan rail is much less susceptible to the bolt-hole distortion commonly found on thin stamped-steel pans.
That gives the gasket a flatter surface to seal against.
This is exactly why Moroso states that its Perm-Align gaskets are recommended for:
Flat-rail cast-aluminum or billet-rail transmission pans.
A reinforced gasket plus a rigid flat pan rail creates a much more controlled sealing interface.
Service the Transmission Filter
If the transmission pan is already removed, inspect the filter.
Moroso recommends:
FT1074 or similar
for its 42025 pan application.
The correct filter depends on the specific transmission and pan configuration, so verify the service part before ordering.
Replacing a pan gasket while ignoring an overdue transmission filter is an excellent way to create another service job sooner than necessary.
Inspect the Pan for Debris
Once the pan is removed, inspect what has accumulated inside.
Look for:
- Fine metallic material
- Friction material
- Large metal fragments
- Sludge
- Burnt fluid
- Water contamination
Some fine material on the magnet can accumulate during normal service.
Large metal pieces or substantial friction material deserve further investigation.
The transmission pan is effectively giving you a free look at what’s happening inside the unit.
Take advantage of it.
Clean the Magnet
If the pan contains a magnet, clean it thoroughly before reinstallation.
The magnet collects ferrous wear material that would otherwise continue circulating in the transmission fluid.
A heavily loaded magnet can also provide clues about internal wear.
Clean it, inspect it and reinstall it correctly.
700R4 vs 4L60
The 700R4 was eventually renamed the 4L60, which is why these names frequently appear together.
The basic naming change did not instantly create an entirely new transmission architecture.
This is also why many service components overlap between:
700R4
and
4L60
However, that doesn’t mean every internal component or calibration is interchangeable across every year.
Always verify the exact transmission before ordering service parts.
4L60 vs 4L60E
The 4L60E introduced electronic transmission control.
The “E” matters.
A 4L60E relies on electronic controls for functions that were handled hydraulically or mechanically on earlier versions.
That distinction becomes especially important for:
- Swaps
- Standalone controllers
- Wiring
- Vehicle-speed signals
- Torque-converter lockup
- Shift control
- Diagnostics
The pan-gasket family overlaps, but the transmissions should not be treated as identical simply because their pans look familiar.
4L65E Compatibility
Moroso also lists genuine 93104 for:
GM 4L65E
The 4L65E is an upgraded member of the same basic transmission family.
That application should be included in the product fitment and SEO data because customers searching specifically for a 4L65E transmission-pan gasket may otherwise miss the product.
Transmission Temperature Matters
Automatic transmission fluid is both a hydraulic fluid and a lubricant.
Excessive heat accelerates fluid degradation and can shorten the life of:
- Clutches
- Seals
- Bushings
- Torque converter
- Valve-body components
Performance vehicles with:
- High-stall converters
- Increased engine output
- Heavy vehicle weight
- Towing loads
- Drag-and-drive use
- Track use
can generate substantially more transmission heat.
A quality gasket stops fluid from leaking.
It does not control transmission temperature.
For demanding applications, consider an appropriately sized transmission cooler.
Moroso Transmission Coolers
Moroso offers external transmission cooling products including:
41200 Transmission Oil Cooler With Filter
and
41205 Heavy-Duty Transmission Cooler/Filter
These can be natural cross-sells for performance 700R4 and 4L60-family builds where additional transmission-fluid cooling is required.
Cooling-system plumbing should always be sized and routed appropriately for the transmission and intended use.
Fluid Level Matters
After pan removal, refill the transmission with the correct fluid according to the transmission builder or vehicle manufacturer’s procedure.
Do not assume the transmission needs exactly the amount that came out.
Capacity can change with:
- Deep transmission pan
- Torque converter
- External cooler
- Cooler lines
- Transmission rebuild
- Converter replacement
Bring the fluid level up gradually and verify it using the proper procedure.
Overfilling an automatic transmission can cause its own problems.
Check for Leaks After Installation
After completing the installation:
- Add the appropriate transmission fluid.
- Start the engine according to the proper procedure.
- Cycle through the required gear positions.
- Bring the transmission to the specified checking condition.
- Verify fluid level.
- Inspect the entire pan rail.
- Inspect cooler connections.
- Inspect the drain plug.
- Recheck after the first drive.
A clean transmission makes spotting a fresh leak considerably easier.
Reusable Design
The supplied product description markets this gasket as a durable reinforced replacement.
A steel-core rubber gasket can potentially be reused when it remains in good condition.
Before reinstalling any used gasket, inspect for:
- Cuts
- Tears
- Hardened rubber
- Permanent deformation
- Separation from steel reinforcement
- Chemical deterioration
- Damaged bolt holes
If there is any doubt about the sealing surface, replace it.
The cost of a gasket is usually considerably lower than the amount of enthusiasm required to remove the pan again.
Important Manufacturing-Claim Clarification
The supplied listing describes this aftermarket gasket as:
Steel-shimmed
High-durometer rubber
Vulcanized
OEM-identical standards
Those claims should remain attributed to the aftermarket manufacturer.
Moroso’s independently verified specification for its genuine 93104 is:
40-durometer rubber vulcanized to a rigid steel frame
Do not combine the two descriptions and accidentally represent the aftermarket gasket as being manufactured to Moroso’s exact construction specification.
What You Get
Product: Transmission oil-pan gasket
Application: GM 700R4 / 4L60 / 4L60E / 4L65E compatible application
Cross-Reference: Moroso 93104 application
Construction: Steel-reinforced vulcanized rubber according to supplier
Thickness: 3/16 inch
Quantity: One gasket
Installation: Rigid bolt-hole-aligned design
Sealant: Supplier states installation without sealant on clean, flat surfaces
Who Should Buy This Gasket?
This gasket is suited to customers servicing compatible:
- GM 700R4
- GM 4L60
- GM 4L60E
- GM 4L65E
- Street performance cars
- Muscle cars
- Hot rods
- Trucks
- Street/strip cars
- Drag-and-drive builds
- Restomods
- Engine/transmission swaps
It’s particularly useful where a rigid reinforced gasket is preferred over conventional cork or soft composite designs.
Final Verdict
This GM 700R4 / 4L60 / 4L60E / 4L65E transmission-pan gasket provides a steel-reinforced, 3/16-inch-thick alternative for customers looking for a replacement compatible with the Moroso 93104 application.
Its rigid construction makes pan alignment easier and is intended to provide consistent compression against clean, flat sealing surfaces.
For performance applications, pair it with a flat transmission-pan rail, service the filter while the pan is removed, inspect the fluid and magnet, and tighten the pan progressively rather than attacking every bolt with maximum enthusiasm.
And if the transmission still leaks afterward, check above the pan before blaming the gasket.
Automatic transmission fluid is remarkably talented at traveling downward.
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