As Tesla ramps up production of the Model 3 and continues to deliver cars to its long list of reservation holders, many buyers are wondering when they will be able to configure Model 3s with "D" all-wheel drive or with the smaller base battery pack.

We can't yet address the smaller battery packs, but CEO Elon Musk left a clue for buyers waiting for all-wheel drive models when he responded to reservation holder Brandon Ledford on Twitter.

Ledford asked for more specific information on when his AWD model might be available, and Musk said Tesla won't build all-wheel drive models until after it reaches its full production rate for the Model 3 configurations now available.

Musk says the problem is that adding any further configurations would make production so much more complicated that it would jeopardize the company's ability to produce the Model 3 at the levels it has long promised.

Previously, the CEO had said that all-wheel drive cars would become available this spring, but struggles getting the initial line up to speed have pushed that date back.

The latest timeframe Musk has given to investors indicates that Model 3 production should crest that magic 5,000 per week number sometime this summer.

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If it doesn't happen by the promised June 30 deadline, then sometime in July, August, or perhaps September.

All-wheel drive models could thus become available just in time for the snow to fly in parts of the U.S. this fall.

Tesla has also said that all-wheel drive models will add the option of air suspension, a feature so popular with Model S buyers that it now comes standard.

2017 Tesla Model 3, 2017 Los Angeles Auto Show

2017 Tesla Model 3, 2017 Los Angeles Auto Show

An all-wheel drive version would also enable Tesla to build a Performance version of the Model 3, as it did with the Model S. 

Before that, though, Tesla will need to satisfy legions of buyers waiting for less expensive versions of the Model 3—Musk's long-promised $35,000 competitor to the BMW 3 Series.

Because Tesla has historically produced its most feature-rich models first, leaving production of base models until later, the AWD "D" Model 3s will likely take priority over the smaller, lower-range battery models.

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So far, all Model 3s produced have had the long-range battery, rated at 310 miles, which adds $9,000 to the base price.

Musk's Tweet should give those buyers some indication how long it will take to get their Model 3s as well.

In other words, the company will ramp up production of basic long-range, rear-wheel drive Model 3s to the promised level, then it will add the "D" models—and then sometime after that, and not before, will it add the smaller-battery version.