Where to get a front pump for a 42RH (A500)

It's got two solenoids on it. And the spring that broke was the 3-4 accumulator spring that's in the valve body. Got one in town for a few bucks. Shouldn't make a huge difference, but maybe I'll get lucky. I figured I should probably blow apart the valve body, but haven't convinced myself yet since this rebuild is turning into a second full time job when I get home. 8 hours to pull the damn trans out, 5 hours to blow it apart and get the clutches swapped, and another 5 hours yesterday fighting trying to get it back together. Not looking foward to trying to get it back in the truck...

Where is the lock up apply piston? Is it just in the valve body somewhere? I did some reading up yesterday on similar issues and read about some possible electronic things to look at. Sounds like the TPS and speed sensor are about all the computer uses to determine lock up. Seems kind of weird though, the speedo works fine, so I assume the speed sensor would be okay and even if the TPS is flakey, it shouldn't be locking up at under 5 mph pulling into a garage. I guess worst case I may just pull the pin out of the connector for lockup if the rebuild doesn't fix things while I sort out the electronics. At least I won't have to drop the trans again to replace solenoids if it comes down to that.