Choosing the Right Transmission Filter Kit for Your 1973-1978 Buick Regal
Keep your classic Regal's automatic transmission shifting smoothly by selecting the correct filter kit.
- You must identify if your Regal has a TH350 or TH400 transmission by its pan shape before buying a kit.
- Symptoms like slipping gears, delayed shifts, or whining noises point to a likely clogged filter.
- Quality aftermarket brands like Wix and ATP are reliable choices for this repair.
- Changing the filter and fluid is a messy but straightforward DIY job that can save on labor costs.
First, Identify Your Transmission: TH350 or TH400?
Before you buy a transmission filter kit for your 1973-1978 Buick Regal, you must know which automatic transmission is in your car. During this era, GM primarily used two different Turbo-Hydramatic transmissions: the TH350 and the heavy-duty TH400. They use different filters and gaskets, so getting the right kit is essential. The TH400 was typically paired with big-block V8 engines, while the TH350 was used with small-block V8s and V6s.
The easiest way to tell them apart is by looking at the shape of the transmission oil pan. 🎬 Watch: How to visually identify your TH350 or TH400 transmission
- TH350 Pan: Mostly square with one corner cut off at an angle. It has 13 bolts.
- TH400 Pan: Has an irregular shape, often compared to the shape of Texas or an abstract kidney. It has 13 bolts.
Symptoms of a Clogged Transmission Filter
A transmission filter doesn't fail suddenly. It clogs over time, restricting fluid flow. If you notice any of these symptoms, your filter may need changing:
🎬 See these 6 warning signs of a clogged transmission filter- Delayed or Erratic Shifting: The car hesitates before going into gear or shifts at the wrong times.
- Transmission Slipping: The engine RPMs might go up, but the car doesn't accelerate as it should, feeling like it's momentarily in neutral.
- Whining or Buzzing Noises: A struggling transmission pump, starved for fluid, can make unusual noises.
- Burnt Smell: Restricted fluid flow leads to overheating, which can burn the transmission fluid and create a distinct smell.
- Fluid Leaks: In some cases, increased pressure from a blockage can cause seals and gaskets to leak.
Choosing the Right Aftermarket Filter Kit
For a vehicle from the 1970s, new OEM parts from GM are generally not available. The aftermarket is your primary source. Quality aftermarket kits are reliable and widely used for these transmissions. The main components are the filter itself and the pan gasket.
Brand Quality Tiers
Based on general reputation and user feedback, here’s how the available brands stack up:
| Tier | Brands | Assessment |
|---|---|---|
| Tier 1: Recommended | Wix, ATP | Both brands have a strong reputation for quality and fitment in the aftermarket community. Wix is well-known for its filtration products across the board. ATP specializes in transmission components and is a trusted choice; their gaskets are sometimes designed to help with installation. You can be confident using kits from these brands. |
| Tier 2: Standard | Premium Guard, Pioneer Cable | These brands provide a functional, budget-friendly option. While less is known about their specific reputation for this application compared to Wix or ATP, they are established aftermarket suppliers. For a standard daily driver, these kits will perform the job. |
A Note on Gaskets
The kit will come with a new pan gasket. Some mechanics prefer to use a separate, high-quality rubber gasket instead of the cork or paper ones included in some kits. ATP is known for a "third hand" gasket that has undersized bolt holes to hold it in place during installation, which can be very helpful. Regardless of the type, ensure the pan surface and transmission mating surface are perfectly clean before installation to prevent leaks.
Estimated Costs for a Transmission Filter Kit Replacement
| Item | Estimated Cost |
|---|---|
| Aftermarket Transmission Filter Kit | $11 - $57 |
| Transmission Fluid (4-5 quarts) | $25 - $50 |
| Shop Labor | $85 - $150 |
| Total (DIY) | $36 - $107 |
| Total (Installed at a Shop) | $121 - $257 |
Frequently Asked Questions
How often should I change my transmission filter?
For a classic car like a '73-'78 Regal, a good rule of thumb is to change the transmission fluid and filter every 30,000 to 50,000 miles, or sooner if you notice any performance issues. Regular changes are the best way to extend the life of your transmission.
Is this a difficult job to do myself?
For a DIY mechanic with some experience, this is a manageable job. The difficulty is low, but it is messy. You'll need a large drain pan, sockets, a scraper for the old gasket, and a torque wrench to properly tighten the pan bolts. The biggest challenges are avoiding a big fluid spill 🎬 Watch: The best way to change your TH350 fluid and filter and ensuring a leak-free seal on the new gasket.
What kind of transmission fluid should I use?
These GM transmissions originally used DEXRON fluid. You should use a modern fluid that is compatible with or listed as a replacement for DEXRON-II or DEXRON-III. Always check the fluid bottle to confirm compatibility.
My kit came with a rubber O-ring. Where does it go?
The small O-ring is for the filter's pickup tube. When you pull the old filter out, the old O-ring may stay up in the transmission housing. Make sure you remove the old one before installing the new filter with its new O-ring to ensure a proper seal.
Helpful Videos
Technical Specifications
The primary specification difference is the transmission application: General Motors TH350 or TH400. The filter and gasket are specific to each transmission type and are not interchangeable. The TH350 kit uses a square-ish pan gasket, while the TH400 kit uses an irregularly shaped gasket.
We Have This Part in Stock
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.
- 🎬 Helpful Videos
- 🛍️ Shop This Part
- First, Identify Your Transmission: TH350 or TH400?
- Symptoms of a Clogged Transmission Filter
- Choosing the Right Aftermarket Filter Kit
- Brand Quality Tiers
- A Note on Gaskets
- Estimated Costs for a Transmission Filter Kit Replacement
- Frequently Asked Questions
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