Beginning in 2004 General Motors and then Daimler-Chrysler (now two separate companies) announced intentions to partner in the development of a special two-mode hybrid drive system for larger SUVs and trucks. The system was originally derived from heavy-duty GM transit buses before GM, Daimler-Chrysler, BMW (beginning later in 2005) decided to co-develop the system for passenger vehicles.

Now after five years of collaboration several reports are speculating that both luxury makers, BMW and Mercedes-Benz, are no longer pursuing two-mode hybrid technology. The reports are based heavily on the fact that both automakers have recently released mild hybrids (2010 Mercedes-Benz S400 Hybrid and 2010 BMW ActiveHybrid 7 sedans) on a shared hybrid-drive system between the two automakers, and do not contain Two-Mode Hybrid technology.

The remaining partner outside of the original creator of the technology, GM, is Chrysler. Chrysler's recent five-year plan did not include any electric-drive vehicles. The report was compiled and driven largely by Chrysler's new owner - Fiat.

According to Greencarreports, the final area of consideration for the end of this partnership lies within the physical research facility itself. The Two-Mode Research and Development facility had been located in Troy, Michigan, but ended in June of this year.

GM has since moved most of its staff back to the Warren engineering center.

GM has as recently as last month indicated its plans for a future involving the Two-Mode Hybrid system at a technical event at the Warren facility. This announcement, coupled with the other announcements and product plans by all of the co-developers, leaves speculators to believe that GM has ultimately retained the technology for itself alone.

The Two-Mode Hybrid system features the combination of an electric continuously variable transmission (eCVT) with two electric motors, four fixed gears, various clutches and planetary gearsets, heavy-duty electronics, and originally, a nickel-metal-hydride battery pack.

The recent event at the Warren lab hinted towards future use of lithium-ion battery technology in the Two-Mode Hybrid system, but it is unclear at this time when the lithium-ion batteries will replace the heavier nickel-metal-hydride batteries currently used in GM's Two-Mode Hybrid system.

The lighter lithium-ion battery technology is the same technology featured in the yet-to-be-released Chevy Volt.