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A main valve and method assembling for use on a machine is disclosed. The main valve may comprise a body, a free wheeling valve, a bypass valve, a flow divider valve, a free wheeling pilot valve, and a flow divider bypass pilot control valve. Each valve may be disposed inside the body. The body may

A main valve and method assembling for use on a machine is disclosed. The main valve may comprise a body, a free wheeling valve, a bypass valve, a flow divider valve, a free wheeling pilot valve, and a flow divider bypass pilot control valve. Each valve may be disposed inside the body. The body may define a plurality of ports and channels between the valves. The free wheeling valve may be operable between a free wheeling mode and a drive assist mode. The bypass valve may have a flow dividing mode that permits fluid communication between the free wheeling valve and the flow divider valve, and a bypass mode that permits fluid communication between the free wheeling valve and first and second bypass channels.

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1. A main valve comprising: a body defining a supply port, a first exit port, a second exit port, an intermediate channel, a flow divider channel, a first bypass channel, a second bypass channel, a free wheeling pilot channel, and a bypass pilot channel;a free wheeling valve disposed in the body and

1. A main valve comprising: a body defining a supply port, a first exit port, a second exit port, an intermediate channel, a flow divider channel, a first bypass channel, a second bypass channel, a free wheeling pilot channel, and a bypass pilot channel;a free wheeling valve disposed in the body and fluidly connected to the supply port, the free wheeling valve operable between a free wheeling mode that blocks fluid flow out of the first and second exit ports by blocking fluid flow between the supply port and a bypass valve, and a drive assist mode that permits fluid flow out of the first and second exit ports by permitting fluid from the supply port to flow to the bypass valve;the bypass valve disposed in the body and fluidly connected to the free wheeling valve by the intermediate channel, the bypass valve fluidly connected to the first and second bypass channels and a flow divider valve, the bypass valve having a flow dividing mode that permits fluid communication between the free wheeling valve and the flow divider valve, and a bypass mode that permits fluid communication between the free wheeling valve and the first and second bypass channels;a flow divider valve disposed in the body and including a flow divider inlet fluidly connected to the bypass valve by the flow divider channel, a first flow divider outlet fluidly connected to the first exit port, and a second flow divider outlet fluidly connected to the second exit port, the flow divider inlet in fluid communication with the first and second flow divider outlets;a free wheeling pilot valve disposed in the body and fluidly connected to the free wheeling valve by the free wheeling pilot channel; anda flow divider bypass pilot control valve disposed in the body and fluidly connected to the bypass valve by the bypass pilot channel. 2. The main valve of claim 1, wherein when the bypass valve is in the flow dividing mode, the bypass valve substantially blocks fluid communication between the bypass valve and the first and second bypass channels. 3. The main valve of claim 1, in which the free wheeling pilot channel includes a first branch and a second branch, wherein the free wheeling valve is fluidly connected to the free wheeling pilot valve by both the first and second branches. 4. The main valve of claim 3, wherein the flow divider bypass pilot control valve is fluidly connected to the free wheeling valve by the first branch of the free wheeling pilot channel. 5. The main valve of claim 1, wherein the flow divider bypass pilot control valve is fluidly connected to the free wheeling valve by the free wheeling pilot channel. 6. The main valve of claim 1, in which the body includes a tank port and a tank channel extending between the bypass valve and the tank port. 7. The main valve of claim 6, wherein the tank channel is disposed in the body to extend between the free wheeling pilot valve and the tank port. 8. The main valve of claim 1, further including a first anti-cavitation valve disposed in the body. 9. A method of assembling a wheel assist drive system on a machine having first and second wheel motors and a primary pump for circulating a hydraulic fluid, the method comprising: providing a main valve that includes: a body defining a supply port, a return port, a first exit port, a second exit port, a return inlet port, a supply channel, an intermediate channel, a flow divider channel, a first exit channel, a second exit channel, a first bypass channel, a second bypass channel, a return channel, a return outlet channel, a free wheeling pilot channel, and a bypass pilot channel;a free wheeling valve disposed in the body, the free wheeling valve fluidly connected to the supply port by the supply channel, the free wheeling valve operable between a free wheeling mode that blocks fluid flow out of the first and second exit ports by blocking fluid flow between the supply port and a bypass valve, and a drive assist mode that permits fluid flow out of the first and second exit ports by permitting fluid from the supply port to flow to the bypass valve;the bypass valve disposed in the body and fluidly connected to the free wheeling valve by the intermediate channel, the bypass valve fluidly connected to the first exit channel by the first bypass channel, the bypass valve fluidly connected to the second exit channel by the second bypass channel, the bypass valve fluidly connected to a flow divider valve, the bypass valve having a flow dividing mode that permits fluid communication between the free wheeling valve and the flow divider valve, and a bypass mode that permits fluid communication between the free wheeling valve and the first and second bypass channels;a flow divider valve disposed in the body and including a flow divider inlet fluidly connected to the bypass valve by a flow divider channel, a first flow divider outlet fluidly connected to the first exit port by the first exit channel, and a second flow divider outlet fluidly connected to the second exit port by the second exit channel, the flow divider inlet in fluid communication with the first and second flow divider outlets;a free wheeling pilot valve disposed in the body and fluidly connected to the free wheeling valve by the free wheeling pilot channel; anda flow divider bypass pilot control valve disposed in the body and fluidly connected to the bypass valve by the bypass pilot channel; andfluidly connecting the main valve to the first and second wheel motors and primary pump. 10. The method of claim 9, in which the machine comprises a motor grader. 11. The method of claim 10, in which the motor grader comprises a pair of rear wheels and a pair of front wheels, and in which the first and second wheel motors are coupled to the pair of front wheels. 12. The method of claim 9, wherein the main valve further includes including a first anti-cavitation valve disposed in the body and in fluid communication with the first exit channel and a second anti-cavitation valve disposed in the body and in fluid communication with the second exit channel. 13. A wheel assist drive system for use on a machine having a primary pump and first and second ground-engaging members, the wheel assist drive system comprising: a hydraulic first wheel motor operably coupled to the first ground-engaging member;a hydraulic second wheel motor operably coupled to the second ground-engaging member;a main valve including: a body defining a supply port, a return port, a first exit port, a second exit port, a return inlet port, a supply channel, an intermediate channel, a flow divider channel, a first exit channel, a second exit channel, a first bypass channel, a second bypass channel, a return channel, a return outlet channel, a free wheeling pilot channel, and a bypass pilot channel;a free wheeling valve disposed in the body, the free wheeling valve including a first free wheeling valve inlet fluidly connected to the supply port by the supply channel, a second free wheeling valve inlet fluidly connected to the return port by the return outlet channel, a first free wheeling valve outlet fluidly connected to the first free wheeling valve inlet, a second free wheeling valve outlet fluidly connected to the second free wheeling valve inlet, the free wheeling valve operable between a free wheeling mode that blocks fluid flow out of the first and second exit ports by blocking fluid between the supply port and the first free wheeling valve outlet, and a drive assist mode that permits fluid flow out of the first and second exit ports by permitting fluid from supply port to flow out of the first free wheeling valve outlet;a bypass valve disposed in the body, the bypass valve including a bypass inlet fluidly connected to the first free wheeling valve outlet by the intermediate channel, a first bypass outlet fluidly connected to the first exit channel by the first bypass channel, a second bypass outlet fluidly connected to the second exit channel by the second bypass channel, and a third bypass outlet, the bypass valve having a flow dividing mode that permits fluid communication between the free wheeling valve and the flow divider valve, and a bypass mode that permits fluid communication between the free wheeling valve and the first and second bypass channels;a flow divider valve disposed in the body and including a flow divider inlet fluidly connected to the third bypass outlet by a flow divider channel, a first flow divider outlet fluidly connected to the first exit port by the first exit channel, and a second flow divider outlet fluidly connected to the second exit port by the second exit channel, the flow divider inlet in fluid communication with the first and second flow divider outlets;a free wheeling pilot valve disposed in the body and fluidly connected to the free wheeling valve by the free wheeling pilot channel; anda flow divider bypass pilot control valve disposed in the body and fluidly connected to the bypass valve by the bypass pilot channel; anda controller operably coupled to the free wheeling valve and the bypass valve, the controller being configured to:determine an activation status of the free wheeling valve;operate the bypass valve in the bypass mode when the free wheeling valve is in the free wheeling mode; andoperate the bypass valve in either of the bypass mode and the flow dividing mode when the free wheeling valve is in the drive assist mode. 14. The wheel assist drive system of claim 13, in which the main valve further includes a first anti-cavitation valve disposed in the body and in fluid communication with a first exit channel. 15. The wheel assist drive system of claim 14, in which the main valve further includes a second anti-cavitation valve disposed in the body and in fluid communication with a second exit channel. 16. The wheel assist drive system of claim 14, in which the body further includes an anti-cavitation channel extending from the first anti-cavitation valve to the free wheeling pilot channel. 17. The wheel assist drive system of claim 13, in which the free wheeling pilot channel includes a first branch and a second branch, wherein the free wheeling valve is fluidly connected to the free wheeling pilot valve by the first branch, and is fluidly connected to the free wheeling pilot valve by the second branch, the first branch separate from the second branch. 18. The wheel assist drive system of claim 13, in which the controller is further configured to operate the free wheeling valve in free wheeling mode when the free wheeling pilot valve and the flow divider bypass pilot control valve are de-energized. 19. The wheel assist drive system of claim 13, in which the controller is further configured to operate the free wheeling valve in a drive assist mode when the free wheeling pilot valve is energized and the flow divider bypass pilot control valve is de-energized. 20. The wheel assist drive system of claim 13, in which the flow divider valve has a first flow mode in which a greater flow of fluid is provided to the first wheel motor, and a second flow mode in which a greater flow of fluid is provided to the second wheel motor, and controller is further configured to operate the bypass valve in flow dividing mode and the flow divider valve in either a first or a second flow mode when both the free wheeling pilot valve and the flow divider bypass control valve are energized and traction control is active.