A two‐dimensionalk‐space simulation of long‐wavelength trapped ion mode turbulence is used to investigate Bohm (macroscopic) versus gyro‐Bohm (microscopic) scaling behavior in tokamaks. A nonlinear two‐field model of dissipative trapped ion turbulence evolving trapped ion and trapped electron density fluctuations shows gyro‐Bohm‐like scaling in contrast to earlier simulation work by Saisonetal. [Plasma Phys.20, 1 (1978)]. In fact, nearly all features of trapped ion mode turbulence and transport originally posited by Kadomtsev and Pogutse [ReviewsofPlasmaPhysics(Consultants Bureau, New York, 1970), Vol. 5, p. 379] are recovered. However, the widely used Kadomtsev–Pogutse one‐field approximation to the two‐field dissipative trapped ion model is unexpectedly found to be unrepresentative with much different fluctuation levels and diffusion. Transformation to a new field basis diagonalizing the linear part of the two‐field equations clarifies the importance of the damped branch not contained in the one‐field equation. The two‐field collisionless trapped ion mode equations are transformed into a parameterless single equation for a complex field providing a perfect scaling relation for the dependence on the driving curvature drifts.