Backhoe John Deere 302A - goes in reverse, but will not go in forward gear

[MyRivers]

Hello,

I'm a newbie and looking for information for my brother. He is working on his John Deere 302A backhoe, which is from the 70's, I believe. He said the problem is that he can do everything in reverse, but nothing in forward, and it's getting hard to get any work done that way. He changed out both of the hydraulic filters, but nothing changed, so he's having a bad day.
He said it has been running fine in forward, but could have been running a little weak in forward, after looking back at the problem. It happened suddenly. If anyone out there has any ideas, please let me hear them. They would be much appreciated.

Thank you!!

 

[Tx Jim]

Check linkage to be sure control valve is shifting into fwd. Also check pressure on RH side on control valve. Pressure should be in the 165# range.