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Peterbilt 320 (1987-1995) Transmission Filter Kit: A Maintenance Guide

Keep your heavy-duty transmission shifting smoothly by understanding when and why to replace your filter kit.

3 minutes to read 1987-1995 Peterbilt 320
Difficulty
2/5
Est. Time
1.5 hrs
DIY Doable?
✅ Yes
Shop Labor
$150-$450
⚠️ Drivable, but... — Driving with a suspected clogged filter is not recommended, as it can lead to severe and expensive transmission damage.
Key Takeaways
  • Regularly changing the transmission filter is a critical preventative maintenance task for the hard-working Peterbilt 320.
  • Symptoms like harsh shifting, gear slippage, or transmission overheating strongly suggest a clogged filter that needs immediate attention.
  • You must verify your truck's specific transmission model (e.g., Allison) before ordering a filter kit to ensure a correct fit.
  • Quality aftermarket kits from brands like ATP are a reliable and cost-effective choice for these older trucks.
The transmission filter kit is a critical maintenance item for your 1987-1995 Peterbilt 320. Your truck's transmission, often an Allison automatic in these vocational models, relies on clean fluid to operate. The filter traps harmful debris like metal shavings and clutch material that naturally wear off over time. This prevents contaminants from clogging sensitive components like the valve body and solenoids, ensuring proper hydraulic pressure for smooth shifting and preventing premature wear. A clean filter is essential for the longevity and performance of your hard-working truck's transmission.

Is Your Peterbilt 320 Showing Signs of a Clogged Transmission Filter?

Because the Peterbilt 320 is a vocational truck often used in demanding stop-and-go applications like refuse collection, its transmission works hard. A clogged filter restricts fluid flow, which can lead to serious and expensive problems. Watch for these warning signs that indicate it's time to service your transmission.

Common Symptoms of a Failing Transmission Filter

  • Harsh or Delayed Shifting: If gear changes become rough, jerky, or delayed, it could mean dirty fluid is interfering with the transmission's internal controls.
  • Gears Slipping: A drop in hydraulic pressure from a clogged filter can cause the transmission to slip out of gear, a potentially dangerous situation.
  • Transmission Overheating: Restricted fluid flow prevents proper cooling, causing the transmission to run hot. Overheating is a leading cause of transmission failure in heavy-duty trucks.
  • Whining or Grinding Noises: Unusual noises from the transmission area can signal that the fluid pump is struggling to pull fluid through a clogged filter.

Don't Ignore the Signs

Continuing to operate your truck with a severely clogged transmission filter can lead to catastrophic transmission failure, resulting in costly repairs and significant downtime.

Choosing the Right Aftermarket Transmission Filter Kit

For a vehicle from the 1987-1995 model years, new aftermarket parts are the most common and practical choice. Finding new OEM parts can be difficult and expensive. High-quality aftermarket brands provide a reliable and affordable solution.

Brand Spotlight: ATP
ATP (Automatic Transmission Parts) is a well-known brand that produces filter kits designed to meet or exceed original specifications. Reviews often point to good quality and fitment. Many ATP kits include their "3rd Hand" pan gasket, which has special holes to hold bolts in place, making installation easier for both DIY mechanics and professionals.

Pro Tip: Match the Part to Your Transmission

The most critical step is to identify the exact transmission model in your Peterbilt 320. These trucks were often equipped with Allison automatic transmissions, but other configurations may exist. The filter kit must match your specific transmission model to ensure proper fit and function. Check your vehicle's service manual or the transmission casing for identification numbers before ordering.

Estimated Costs for Transmission Filter Replacement

Part/Service Estimated Cost
New Aftermarket Transmission Filter Kit $94 - $131
Shop Labor $150 - $450
Total Estimated Cost $244 - $581

Note: Costs are estimates and can vary based on your location, the specific parts required, and your mechanic's labor rates. Fluid cost is additional.

Frequently Asked Questions

How often should I change my transmission filter?

For a heavy-duty truck like the Peterbilt 320, it's best to follow the service intervals recommended in your transmission's service manual. If you don't have the manual, a general guideline for vehicles in severe service is to inspect or change the fluid and filter every 25,000 to 50,000 miles. Regular changes are key to preventing problems.

What's included in a typical transmission filter kit?

A kit usually contains the transmission filter(s) and a new pan gasket. Some kits may also include O-rings or seals required for the job. The ATP brand, for example, is known for including all necessary components for a filter change.

Is an aftermarket filter kit a good choice for my Peterbilt?

Yes. For vehicles of this age, quality aftermarket parts from reputable brands like ATP are a perfectly acceptable and cost-effective option. They are designed to function just like the original parts and are often the only readily available option.

Were there any recalls for the 1987-1995 Peterbilt 320 transmission?

Searches of the NHTSA database did not show any specific recalls related to the transmission filter or widespread transmission failures for the 1987-1995 Peterbilt 320. Recent Peterbilt recalls are for much newer models and different issues.

Technical Specifications

The key specification is matching the filter kit to the exact transmission model installed in your truck (e.g., Allison HT/MD series, etc.). Part numbers vary by transmission, not by the truck model itself. The kit should include the filter and a pan gasket.

Wrenchy
Article researched & written by
Go-Parts' AI research assistant. Every article is backed by live web research, verified OEM data, and real technician knowledge — so you get accurate, up-to-date information you can trust.
Meet Wrenchy → Updated Jul 21, 2026

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.

Year Coverage
This article covers the Transmission Filter Kit for:
  • Peterbilt 320: 198719881989199019911992199319941995
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