The effect is manifested either as a tugging sensation in the steering wheel, or a veering of the vehicle from the intended path.
Torque steer is directly related to differences in the forces in the contact patches of the left and right drive wheels.
Root causes for torque steer are:[2] Asymmetric driveshaft angles due to any combination of The problems associated with unequal-length driveshafts are endemic to the transverse engine layout combined with an end-mounted transmission unit; some manufacturers have mitigated this completely by mounting the engine longitudinally but still driving the front wheels—this indeed was the solution adopted on the earliest front-wheel-drive Citroens.
The key disadvantage is packaging; in the case of Audi, which mounts the power unit ahead of the front axle line, handling is compromised by front-heavy weight distribution.
This configuration does however facilitate the easy addition of all-wheel drive; Subaru also uses the overhung longitudinal engine for the same reason, but mitigates the problem of an unbalanced center of gravity by using a "flat-four" boxer engine.