it could stall the engine because there’s no slip to allow the engine to idle while the car is stationary. You need to have this checked by a transmission specialist who may have seen this very thing ...
Allison Transmission is collaborating with Cummins Inc to integrate and certify a Cummins B-Series engine with the Allison eGen Flex® electric hybrid propulsion system for the transit market.
An initial proof-of-concept was assembled using the longitudinal engine-transmission package from the Renault LeCar ... The car was sold to competitors in kit form, but to facilitate technical support ...