D35 pig pull

The d35 has a significant steering pull to the left any reason why

 

Only when accelerating?
That's called torque steer... iirc

 

it does it with some of the d series

 

Torque. The engine twists, this puts downward force on one side of the frame, and lifts upwards on the otherside. When you're using the beam or solid front axle, the twisting causes the steering rack to move, basically bumpsteer but caused by torque.

 

Does it only pull when accelerating?

 

Torque steer is with FWD cars only, though it's very similar to what's occurring in the D-series and other powerful RWD cars.

 

D15 comes also an AWD/4WD

 

When spawned on grid map full throttle gets extreme pull to the left until i hit a bump still full throttle then some times i notice a pull

 

Yes, you're right, but I just tested it and it doesn't seem to matter whether it's 2WD or 4WD. What DOES matter it seems is the front suspension, as I suspected. Using the Solid Front Axle, it veers to the left on acceleration, but if I switch to the Offroad Independent suspension it accelerates almost perfectly straight.

Try it if you'd like.