How to replace an Eaton Supercharger Coupler

Does your EATON supercharger make a rattling sound, sort of like rocks rattling around? Is the noise very distinct during idle or low speeds and then soften up as you drive your vehicle?

As long as your supercharger is not leaking oil the chances are your coupler is worn and needs to be replaced.

Since the supercharger coupler is made of plastic, over time the holes on the coupler become worn out. Once the supercharger coupler wears out your supercharger will start making a rattling sound mostly at idle or low engine speeds. If you continue to drive for a long period of time with a warn out coupler, it will cause your bearings and seals to go bad and then you will need a rebuild of the supercharger.

Where in the supercharger is the supercharger coupler located?

The Eaton supercharger has a front nose cone and the main supercharger body. Between the two pieces is a supercharger coupler, which is a little plastic round part with several holes in it.

Supercharger Coupler

The purpose of the supercharger coupler is to connect the front nose to the gears of the superchargers so that it can allow the internal parts of the supercharger to spin together. The supercharger coupler prevents the supercharger from gear damage by absorbing the shock load that can be caused by increase throttle, and it forces the flex of the supercharger coupler rather than breaking the teeth on the superchargers gears.

How long does it take?

These supercharger couplers are very simple to replace and are very inexpensive compared to a supercharger rebuild. All together the replacement of the coupler will take around 1-2 hours complete.

What do I need to change out the supercharger coupler?

You only need a handful of common tools like a Standard Wrench, Allen Wrench, and a Spray Bottle or Syringe to get the old supercharger oil out. You will also need a supercharger nose cone service kit, which includes the special supercharger oil, the new supercharger coupler, gasket maker, and a new oil fill bolt.

How to get the oil out of the supercharger

You want to make sure you drain the old oil out of the supercharger. Since these Eaton superchargers do not have an oil drain plug, you normally will have to drain the oil from the oil fill hole. We find that using an old spay bottle works very well and since most people have them laying around the house it does not require you to make a special trip to the store. You can also use a syringe or a baster depending on what is available to you.

Most superchargers have around 4-6 ounces of supercharger oil inside of the supercharger.

How to take the nose cone off?

Now that the supercharger oil is drained, you can begin to undo the screws that hold the supercharger nose cone to the main body of the supercharger. Most Eaton superchargers have around 6-8 bolts that will hold the supercharger nose cone onto the body.

Replace Supercharger Coupler

Once all the bolts are taken off you can now pull apart the supercharger nose cone from the main supercharger housing. The supercharger coupler will be located right on the pins of the supercharger. Just take out the old coupler and replace it with the new one.

Once the coupler is installed you will want to make sure the supercharger nose cone and supercharger main body is clean of any silicone. Make sure to clean the surface and apply the new gasket maker onto the housing. And then put the supercharger nose cone back into the main supercharger body and tighten the bolts that hold the two pieces together.

You will want to torque these bolts to around 18-20 foot-pounds to torque.

How to fill up the supercharger with supercharger oil

You pretty much are almost complete with the coupler change. All that is left is to fill up the supercharger with the special supercharger oil. Be careful and do NOT overfill the supercharger with oil. If you over fill the supercharger oil beyond the recommended oil requirements, it can cause the oil to expand and leak out of the supercharger seals. If this happens you will need to get a rebuild performed.

For proper oil level please see the oil chart.

How often should I change the supercharger oil?

We recommend changing the oil at or around 100k miles depending on usage. Please make sure you do NOT use any other type of oil, including synthetic motor oils. These will cause failure. Only use Supercharger Oil made specifically for Eaton Superchargers.

7 thoughts on “How to replace an Eaton Supercharger Coupler

  1. Hello guys ,my issue is a bit different , mi 99 lightning rattles when I hit the gas on It and White smoke comes from the exhaust pipe . The mechanic said is due to a failure with the supercharger , what do you think. ?

  2. My 03 xttera super charger makes a high whistle under load and a burnt candle smell occasionally ,seems to come from driver side not in exhaust but will come through heater…any thought about what is going on?

  3. Hi ..
    My supercharger used to make intermite sound when cold .Removed the and found thecoupler have play .I have changed the needle and snout bearing also.
    I have started car it become now worst .It sound like countinous ratteling at idle .
    Any idea please .Can wrong oil cause such rattelling ..or i have install the coupler in wrong way

  4. Quite informative! I just bought a factory supercharged ’97 Buick Riviera with only 64,000 miles and it seems to have the telltale coupler rattle at idle. You say if this rattle is allowed to persist it will damage the bearings and seals; I am ordering a new coupler but I’m just wondering, How bad is it to drive the car a bit before I replace the coupling… does the damage occur in a hundred miles, a few hundred miles or a few thousand, or what?


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