Toyota truck unit Hino Motors Ltd will join in the pact to jointly develop small commercial trucks of the future, including connected vehicles and fuel cell technologies, the automakers said.

Connected vehicles can share internet access and data with devices outside the vehicle, making them more efficient.

Under the deal, Toyota will acquire 39 million treasury shares in Isuzu, worth 42.8 billion yen ($393.89 million), taking a 4.6% stake, the automakers said.

Toyota and Isuzu in 2018 dissolved a previous, 12-year capital tie-up that had focused on diesel engines.

The move on Wednesday comes as traditional automakers face growing competition from tech giants and other rivals developing electric and driverless cars.

Toyota Motor President Akio Toyoda said the push for electric vehicles and carbon neutrality gave the companies a reason to get together again.

"We had tried to jointly develop small diesel engines together... but we didn't really identify specific projects much, and we decided to split and find our own ways," he told a news conference. "But then EV became a new common ground for us again, where common research and development could take place."

For Isuzu, the new partnership with Hino made "perfect sense for our customers," said its President Masanori Katayama, adding that the two companies account for 80% of the commercial vehicles market in Japan.

"Certainly, this partnership of Isuzu and Hino will make sense in revolutionising logistics business overall," he said.

While Isuzu and Hino remain competitors, they could also work together in some of the areas that users are most interested in, the Toyota president said.

The three companies will also set up a new joint venture, Commercial Japan Partnership Technologies Corporation, with Toyota owning 80% and the others owning 10% each.

The company, which will begin operation in April, will implement projects such as introducing fuel cell electric vehicle trucks at events in Fukushima prefecture.

Toyota shares fell 2.2%, mostly in line with the broader Tokyo stock market, but shares of Isuzu Motors Ltd ended up 5.4%. Hino Motors Ltd finished Wednesday trade down 1%.

($1 = 108.6600 yen)

(Reporting by Chang-Ran Kim, Eimi Yamamitsu; Editing by Christopher Cushing, Kim Coghill and Gerry Doyle)

By Eimi Yamamitsu