PAI 131655 Gear Housing Gasket – Cummins ISX ISX15 QSX X15

The PAI 131655 is a premium aftermarket gear housing gasket (also known as front timing cover gasket) for Cummins ISX, ISX15, QSX, and X15 heavy-duty diesel engines. This gasket seals the front gear housing cover to the engine block, preventing oil leaks from the timing gear train area. Manufactured by PAI Industries to meet or exceed OEM specifications, this gasket provides a reliable seal to maintain proper lubrication and protect critical engine components.

Signs You Need a New Gear Housing Gasket

• Oil leak from front of engine near timing cover area
• Visible oil seepage around gear housing perimeter
• Oil dripping onto serpentine belt or accessories
• Low oil level with no other visible external leaks
• Oil residue or buildup on front engine components
• Failed emissions inspection due to oil contamination
• Gasket replacement required during front seal or gear train service

Specifications

Cross References

This gasket replaces or is equivalent to the following part numbers:

• Cummins: 3680876, 3681145, 4026694, 4089757, 4101883, 4985562
• Interstate McBee: M-4026694, M-4089757, M-4985562
• PAI: 131655

Engine Applications

This gear housing gasket fits the following Cummins engine models:

• Cummins ISX – All 11.9L and 15.0L variants (1997-2016)
• Cummins ISX15 – 14.9L (2010+)
• Cummins QSX15 – Industrial/Off-Highway applications
• Cummins X15 – EPA 2017+ (CM2350/CM2450)

Vehicle Applications

Cummins ISX/ISX15/X15 engines are found in Class 8 trucks from major manufacturers:

• Freightliner: Cascadia, Coronado, 122SD, 114SD (2001+)
• Kenworth: W900, W990, T880, T680, T800, C500 (2001+)
• Peterbilt: 389, 579, 567, 386, 387, 388, 367, 365 (2001+)
• International: LT, HX, LoneStar, ProStar, 9900i (2001+)
• Western Star: 4900, 5700XE (2001+)
• Volvo: VNL, VNX Series (with Cummins ISX option)
• Mack: Pinnacle, Anthem (with Cummins ISX option)

When to Replace

The gear housing gasket should be inspected and typically replaced when performing major front-of-engine service including front crankshaft seal replacement, timing gear service, accessory drive repair, or any time the gear housing cover is removed. Oil leaks from this area can contaminate the serpentine belt and accessories, potentially causing belt slip or premature failure. Early detection and replacement of a failing gasket prevents more extensive repairs and maintains proper engine oil levels.

Installation Notes

Thoroughly clean both the gear housing cover and engine block mating surfaces before installation. Remove all old gasket material and debris. Inspect the gear housing cover for warping or damage. Install the gasket dry (no sealant required on gasket surfaces). Apply RTV sealant only at corners where the oil pan meets the block per Cummins service recommendations. Torque gear housing bolts to Cummins specifications in the proper sequence.

Verify your engine serial number and CPL/CM code before ordering to confirm fitment for your specific ISX/X15 configuration.

Handling Time
At All Pro Truck Parts we do our best to ship all orders the same day for orders placed before 12:00 PM Central Standard Time. Same-day shipment is never guaranteed. For standard UPS shipping, you will typically receive your package in 1 - 5 business days. Shipping times are never guaranteed and All Pro Truck Parts is not responsible for lost or delayed shipments by the carrier. Carrier times vary by distance from shipment origin and may change without prior notice. Shipping price is calculated from package dimensions and weight. Calculated rates for orders will be available at checkout. Orders placed after 12:00 PM CST on Fridays will not be fulfilled until the following business day, Monday morning barring a holiday.

Next Day Air Shipments
The cutoff time for UPS Next Day Air is 12:00 PM CST. Orders for Next Day Air placed after 12:00 PM CST will ship the following business day.

Incorrect Shipping Prices
All Pro Truck Parts reserves the right to cancel any order in the event shipping rates are calculated incorrectly at checkout. We will notify you at your provided contact information to give you the option to pay the correct amount, or allow you to cancel the order for a full refund.

Shipping Destinations
All Pro Truck Parts ships within the United States only. We do not currently offer international shipping.

Damaged Shipments
All Pro Truck Parts is not responsible for damage that occurs in transit - responsibility for damaged shipments lies with the carrier. However, we are glad to assist by filing a claim with the carrier on your behalf.

If your package arrives damaged, please do the following:

1. Refuse delivery if the package is visibly damaged at the time of arrival, and note the damage with the driver.
2. If the damage is discovered after delivery, photograph the outer packaging BEFORE opening the box, then photograph the contents showing the damage.
3. Keep all original packaging, including boxes, packing materials, and labels. Carriers may require an inspection before approving a claim.
4. Notify us within 48 hours of delivery by submitting a damaged shipment report at help.allprotruckparts.com/damaged-shipment.

Once a claim has been filed, resolution is determined by the carrier. Refunds and replacements for damaged shipments will only be issued after the carrier approves the claim. Failure to report damage within 48 hours, discarding the original packaging, or opening a visibly damaged package without photographing it first may result in the carrier denying the claim, in which case we are unable to refund or replace the item.

Shipping Services

• UPS Shipping Services
• UPS Ground
• UPS 2nd Day Air A.M. (commercial addresses only)
• UPS 2nd Day Air
• UPS 3 Day Select
• UPS Next Day Air Saver
• UPS Next Day Air
• UPS Next Day Air Early

Returns
All Pro Truck Parts offers lifetime returns for any reason on NEW, UNOPENED items in the original packaging, with exceptions (see restocking fee, excluded categories, used items, sale items and special order items below).
To be eligible for a return, your item must be unused and in the same condition that you received it. It must also be in the original packaging.

Restocking fee and return shipping
Returns of new, unopened items are subject to a 20% restocking fee, which is deducted from your refund. You pay the shipping to send the item back, and shipping costs are not refunded.

Excluded categories
Engines cannot be returned. If one is defective, see defective parts (warranty) below.

Used items (if applicable)
Items marked as USED at the time of sale will be accepted for return up to 30 days from the date of sale.

Defective parts (warranty)
A part that fails is handled through the manufacturer's warranty process, not as a return. The manufacturer reviews the claim and decides whether the part is defective for the application it was purchased for. If you need a part right away, you will need to purchase a replacement rather than wait on the warranty review. Start a warranty claim at help.allprotruckparts.com.

Sale items (if applicable)
Only regular priced items may be refunded. Sale items cannot be refunded.

Special order items (if applicable)
Special order items may be eligible for a refund. The decision to accept a special order item for refund is left solely to the All Pro Truck Parts management team.

How to start a return
Start your return online at help.allprotruckparts.com/returns with your email or phone number and order number. Questions? Text us at (903) 527-5854 or email sales@allprotruckparts.com.
Ship your return to: All Pro Truck Parts, 3948 Interstate 30 W, Caddo Mills TX 75135, United States.
You are responsible for paying the shipping costs to return your item. Shipping costs are non-refundable. If you are shipping an item over $75, we advise using a trackable shipping service or purchasing shipping insurance. We don’t guarantee that we will receive your returned item.

Refunds
Once your returned item is received and inspected, we will send you an email to let you know we received it and whether your refund is approved.
If approved, your refund will be processed and credited to your credit card or original method of payment within 7 business days. For orders paid on our card terminal, text or email us to start the refund.

"Free Shipping" orders
If we paid the shipping on your order ("Free Shipping"), the cost of shipping it to you will be deducted from your refund when the item is returned and inspected.

Exchanges
We only replace items if they are defective or damaged. If you need to exchange it for the same item, start it at help.allprotruckparts.com/returns or text or email us, and send your item to the return address above.

Read our full return policy.