Finally have everything running the way I want, and everything fitting in that removing the cab to plug in the power isn't a hassle. I rearranged some of the electrical components. The receiver and brushless ESC I wrapped in Kapton tape and then copper tape. Took the box off of the receiver and stock heat shrink off of the ESC. Added more magnets so that the body sticks to the chassis better and added some between the cab and body.
I fixed the track chain skipping by removing the plastic I added and inserting a short tungsten slug in the middle of the spring. I measured so that each side had about an 1/8" of give. Also used some cuttable tungsten, and tungsten putty to wrap around the slug and cut piece to keep them centered in the spring. All the tungsten is from my train hobby. The tungsten weights are sold for Pine Derby cars. Anyway, it was a bear to put the chain on but a credit card around the sprung idler helped it slide on. Also put one of the chains on backwards after struggling with it. Everything runs well now, played for about 20 minutes.
Just small details left.
Oh and limited the pump to 80%, much easier to control. Not sure what its called, I just have this Limits setting on the radio.