1978-1981 Dodge D400 Transmission Filter Kit: A Mechanic's Guide
Keep your D400's automatic transmission shifting strong by understanding this critical part.
- Your D400 likely has the durable A727 TorqueFlite transmission; verify this by its 14-bolt pan before buying a kit.
- Symptoms like whining, delayed shifting, or fluid leaks point to a clogged filter that needs immediate attention.
- Aftermarket is the only option; brands like Wix are well-regarded for their quality, especially the included gasket.
- This is a messy but manageable DIY job; the biggest key to success is keeping everything clean to prevent leaks.
Is Your Transmission Filter Clogged?
On a workhorse truck like the D400, the transmission will let you know when it's having problems. A clogged filter starves the internal parts of clean fluid, which can lead to major failures. Watch for these signs:
- Whining or Buzzing Noises: A whining sound that changes with engine RPM can be the transmission's pump struggling to pull fluid through a blocked filter.
- Delayed or Rough Shifts: If your truck hesitates for a moment before engaging Drive or Reverse, it's a classic sign of low hydraulic pressure, often caused by a clogged filter.
- Slipping Gears: If the transmission seems to slip out of gear, or the engine RPMs flare up during shifts, it's a serious symptom that the transmission isn't getting the fluid pressure it needs.
- Fluid Leaks: A clogged filter can cause pressure to build up, forcing red transmission fluid past gaskets and seals.
- Burnt Smell: A distinct burning smell indicates the transmission fluid is overheating, a condition made worse by a restricted filter.
Pro Tip: Check Your Fluid
Regularly check your transmission fluid. It should be bright red and clear. If the fluid on the dipstick looks dark brown, black, or smells burnt, it's time to service the transmission and change the filter.
Choosing the Right Aftermarket Filter Kit
For a vehicle from this era, finding a new OEM Mopar filter kit is highly unlikely. The aftermarket is your only practical choice, and it offers good quality options. The main difference between kits is often the quality of the filter media and, most importantly, the pan gasket.
Your D400 almost certainly has the A727 transmission, which can be identified by its irregular-shaped 14-bolt pan. Always confirm this before purchasing.
Brand Quality
When shopping for a filter kit, you'll encounter different brands. Here's a general breakdown:
- Wix: Often considered a premium aftermarket brand, Wix is well-regarded by professional mechanics for its quality construction and reliable filtration. Their kits typically come with a high-quality gasket, which helps prevent leaks after the service.
- Premium Guard: This is a standard replacement brand that offers a cost-effective solution. While functional, pay close attention to the included gasket. Some mechanics prefer to buy a separate, higher-quality gasket when using budget-friendly kits.
Warning: Verify Fitment
Online parts catalogs can sometimes have conflicting information for older vehicles. Cross-references show that Wix part number 58707 is often associated with the A727 transmission. However, always use a tool to verify the part number with your specific vehicle's details before ordering.
Estimated Replacement Costs
Replacing the transmission filter is a common maintenance item. Prices are estimates and can vary by location and your specific truck's condition.
| Part Type | Estimated Cost |
|---|---|
| New Aftermarket Filter Kit | $17.22 - $18.68 |
| Shop Labor | $100 - $200 |
| Total Estimated Cost | $117 - $219 |
Frequently Asked Questions (FAQ)
Can I replace the transmission filter myself?
Yes, this is a very common DIY job. The main challenges are the mess from the transmission fluid and ensuring the pan and transmission mating surfaces are perfectly clean before installing the new gasket. It involves draining the fluid, removing about 14 bolts, dropping the pan, replacing the filter, and reinstalling everything.
How often should I change the transmission filter?
For a classic truck like the D400, a good rule of thumb is to change the fluid and filter every 30,000 miles for regular use. If you tow heavy loads or operate in extreme conditions, consider doing it more frequently.
What kind of fluid should I use?
The A727 transmission originally used Dexron/Mercon or Chrysler's ATF+. Modern equivalents like ATF+4 are often recommended, but you should always consult your service manual or a trusted mechanic for the correct fluid type to avoid damage.
Are there any recalls or TSBs for the D400 transmission filter?
No, searches of the NHTSA database and other official sources show no recalls or Technical Service Bulletins (TSBs) specifically for the transmission filter kit on the 1978-1981 Dodge D400.
Technical Specifications
Fits Chrysler/Dodge A727 (TorqueFlite 8) automatic transmissions. Kit includes one filter (felt or dacron type) and one 14-bolt pan gasket.
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The information in this article is provided for general reference and educational purposes only. Vehicle specifications, procedures, and part compatibility can vary by production date, trim level, and region. Always consult your vehicle's factory service manual and verify part numbers before purchasing or performing repairs. Safety-critical components such as airbags, seat belts, and braking systems should be installed by a qualified professional.