Sadly for me and my checkbook, I've done everything on my 300TE SLS except replace the valve. System works perfectly knock on wood.

Just because foamy fluidy stuff is coming out the bleed valve, don't assume the pump is working. Nothing's returning to the tank right?

I finally figured out that to check the pump, you must disconnect the high pressure supply hose where it junctions the metal line that goes to the leveling valve. That connection is under the hood, passenger side, near the coolant expansion tank. Disconnect it carefully.

Fill the hydraulic fluid reservoir with fluid, place the supply hose in a bucket, turn on the engine, and run it up to about 2500 rpm. Watch the fluid level.

If nothing's coming out the supply hose except foamy junk, pump is bad.

Also, the hose from the reservoir to the pump can disintegrate over time and close up. That's low pressure into the pump, so it doesn't take much to block that hose.

However, if level of hydraulic fluid in the reservoir is clearly lowering and the fluid going into the bucket is not foamy but clear normal colored fluid, pump OK.