2004 Club Car - Goes in Reverse but not Forward

[bamachem]

I have a new-to-me 2004 Club car DS Sepex cart I'm having issues with. I purchased the cart locally and it was a great deal because it was in pieces, literally. It had at least two questionable batteries, and came with original Club Car charger. I was told it had an "upgraded controller" but it's a Curtis 1510. Maybe it's just been unlocked to speed setting 4. It's decently quick on the 22" tires, when it runs.

I installed 6 new Trojan T875s, installed custom 2GA battery connectors made from welding leads, and replaced the positive lead to the solenoid with 2GA as well. I charged the batteries overnight and the charger shut off as expected.

After working on a custom winch bumper all morning I decided to go for a ride. It would run maybe 30 seconds and then power would cut out. Let go of the accelerator and reapply and it would run for 20-30 more seconds before cutting out. On a hill, it had a hard time making it up due to the motor/controller cutting out, almost as if it had an over-current issue.

I came home, and decided to clean the solenoid contacts and motor contacts. I used a wire wheel on a drill, then coated each with some dielectric grease before snuggling down the connections. When I was cleaning the post at A2 on the motor, the wire wheel came into contact with either F2 or the motor housing and sparked via electrical arc.

Now the cart will not move in forward, but will run great in reverse. In forward, the solenoid will click in to engage, but barely any power gets to the motor, and the solenoid cuts off after 1 second. Again, all is fine in reverse.

I've gone back and checked all connections, jogged the F-N-R toggle switch, and still can't get any response in FWD. Did I fry the Curtis 1510-5201 controller or is it likely the ADC motor?

Any and all suggestions for troubleshooting would be helpful.