I appreciate any guidance in advance.

We've got a E50Z that moves as fast as an earthworm. We've checked the battery, it's good (lift works great too, and checked voltage). Ohm'ed out the foot petal, getting a fair range for output resistance. It does go a little slower/faster when petal is higher/lower. I checked the danaher ac superdrive 3 phase output. It's getting 36v on its input, but only putting out 3-6v on the 3ph AC output. When it is driving, I'm seeing about 130 amps DC on the 36v battery cable when in crawling speed. After going maybe 50 ft or so, it starts error'ing out with a code 52. I'm thinking this may be an overheating indicator? (I've got a thermal camera, I'll check it, camera is from my beekeeping hobby) If I disconnect the 3ph output from the motor, I'm seeing the full voltage coming out of the superdrive.

And one weird thing. Going back & forth, one time it started going faster & then slow & faster again. We were thinking it was the petal sensor (it sat a long time), but now it's stopped doing the faster mode again. Oh, and it doesn't matter if I pick mode 1 / 2 / 3 / 4, same super slow for all of them.

I originally thought it was the battery. But it's got good voltage when trying to drive (1 volt drop from off to moving). Then thought it might be the petal sensor, but it is showing reasonable resistance readings. After that, the superdrive, but it's putting out full voltage when disconnected. Now thinking it might be the encoder or the drive motor itself.

So, questions:
1) Is 130 amps about the right power draw for moving at 1-2 inches/second speed? (would indicate motor issue)
2) Is that speed about right for 5v AC on the superdrive 3 phase output?
3) Could the encoder be the issue?
4) Is it possible to replace either the encoder or the motor without pulling the battery?

Again, guidance greatly appreciated.
Tony

UPDATE:
First, my DC current clamp was having issues. Running diagnostics, the forklift showed that at slow speeds the motor is drawing about 650 amps. It's a 460 amp motor. One cool diagnostic method, we pulled off the battery so we could see the motor. I went back & forth 3 ft a few times. Then I used my thermal camera, and the cables to the motor were 25F warmer than anything else. That confirms the 650 amp reading is accurate. Looks like a bad motor, but I'm open to any additional comments/guidance?