[Closed] Differential lock for setting vehicle

I am using 3DS Max 2015 version. I am trying to make a differential lock of a vehicle.
Here’s what I want to happen:

1. I want “A” and “B” to have different speed.

2. Here I made a rectangle that serves as a “control bar”

3. The “A” cylinder should be faster than the “B” cylinder if the control bar is in the left position.

4. The “B” cylinder should be faster than the “A” cylinder if the control bar is in the right position.

5. “A” and “B” cylinders should have the same speed if the control bar is in the center.

So I made this:

But I am not having my desired results.
The gear is running at a constant speed. And I created a key by animating a red square from left to right.
This animation key is set between 100 and 130 frames. When the red control bar is animated from the left (100frames) to the right (130frames), the “B” cylinder needs to be faster than 100frames.
Whenever I play the animation and move between 100 ~ 130 frames, the “B” cylinder moves more than what I intended it to be. It seems that “B” cylinder feels like it is already rotating at 100-130 frames when the control bar is still at the 100 frame.
I uploaded my file for anyone to check out. I hope someone can help me, thank you!

https://drive.google.com/open?id=1V4okrzTGj7oHqki4z3-46LcPI4sKNizh