In perhaps the best demonstration yet of the TNGA platform architecture's flexibility, Toyota's North American engineering division has added the option of all-wheel drive to two sedans as a mid-cycle enhancement. The 2020 Toyota Camry and the 2021 Toyota Avalon were not "package-protected" for AWD when their designs were first conceived but having a third platform mate (the Toyota RAV4) that does have AWD greatly simplified the engineering and parts-procurement processes. Here's how Toyota added AWD to the mid-cycle-enhanced Camry and Avalon.

A lot of parts are shared with the RAV4, including the 2.5-liter four-cylinder engine, the transmission and transfer case, the rear differential, rear suspension carrier, and rear suspension links. The middle and rear sections of the prop shaft are also shared, with the front section varying in length to accommodate the three different wheelbases. All gear and axle ratios are also shared, which means that relative to the front-drive Camry, the AWD model's overall gearing is shortened by 12 percent to provide the desired launch feel and ensure the engine can tug the roughly 165 extra pounds that AWD adds. That extra mass, friction, and gearing will cost the Camry a bit on the EPA fuel-economy ratings. It's worth noting that the 2.5-liter AWD drivetrain weighs about the same as the Avalon's 3.5-liter front-drive setup, but here the gearing ends up 15 to 20 percent shorter than with the V-6 (which gets completely different transmission ratios). This will be Toyota's first non-hybrid four-cylinder Avalon.

As on the RAV4 AWD LE and XLE trim levels, the Dynamic Torque Control AWD system includes an electromagnetic coupler that disengages torque to the rear wheels above 15 mph whenever all-wheel drive is not needed. The prop shaft continues spinning, however. The max torque split is 50/50 front/rear, and the rear differential is open, so a spinning rear wheel can only be reined in with the brakes.

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To get this three-piece prop shaft and exhaust system to fit required three new floor pan stampings. The front one, spanning the front and rear footwells features a small but noticeable bump on the passenger side. Camry and Avalon each get their own versions of this piece, and each is welded in using the same welding and sealing procedures, so the robots don't need to learn any new tricks. The middle stamping, which runs under the rear seat and over the rear suspension is also new to accommodate the RAV4's saddle-style fuel tank (which reduces capacity from 16.0 to 14.4 gallons) and is shared on both sedans. So is the rear one, which incorporates the spare-tire well, and which required a new structural element to properly engage the tire with the rear differential and prop shafts in a severe rear impact.

The exhaust system does hang down slightly lower, but new front and rear springs are fitted. They're altered to account for the mass difference and to raise the bodywork 0.2 inch to preserve the same ground clearance to this newly positioned exhaust.

Even with all these changes, the exhaust systems had to shrink very slightly, inducing more back-pressure. This lowers the engine's output by 1 hp on both single and dual-exhaust models (from 203 and 206 to 202 and 205 hp) and by 2 lb-ft on single exhaust (Camry LE, SE, XLE) and by 1 on the XSE with dual rear exhaust pipes (from 184 and 186 to 182 and 185 lb-ft—Avalon AWD models get the higher-output dual rear exhaust setup).

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Apart from the small bump out on the passenger floor center tunnel area, owners and passengers will notice very little difference on AWD models. The trunk volume is unchanged, but the revised floorpan elevates the rear seat area by the same 0.4 inch as in the hybrid models, reducing headroom by the same amount in both cars.

The 2020 Toyota Camry—read our review here—enters production in March and will hit dealerships this spring, while the 2021 Toyota Avalon—and that review here—goes on sale this fall. Pricing has yet to be finalized, but we are told to expect the AWD option to be available on four-cylinder Camrys, LE grade and up, as a stand-alone option priced at about $1,500. Avalon buyers will likely face a no-cost option of V-6 front-drive or four-cylinder AWD at the same price on XLE or Limited grades. So expect to spend between $27,425 and $32,460 on a Camry AWD; and $36,830 to $43,130 for an Avalon AWD.