on those give it a shot and change all the transmission fluid with a BG flush. I have cured a few trannies on the Bmw RR with that surging. It might work and it might not. But consider it diagnosis. If it fails then you need a new transmission. This requires all sixteen quarts, not the pan, pull the pan and chances are it may not shift at all. also have them check to make sure the radiator isn't stuffed. There is a bulletin about the transmission having issues after the radiator gets plugged, open the drain **** and if very little flows out then its plugged.

2004 is a completely different transmission and trans ecu.

 

My take on transmissions...

Its moving parts.

The fluid cleans the moving parts and takes the particles to the filter.

Eventually the particles build up on parts as well...

Why would you want to keep changing the fluid?

When you get into a trans and see the black fine powdery build ups on the parts, that's metal.

Changing the fluid helps reduce these buildups.

Changing the fluid helps keep the fluid clean and fresh.

Take some fluid out of a fresh bottle, dab it on white clean rag. Then take some out of your trans. If there is a major difference in the color and tranparency then you should do a trans fluid change. Look at your fluids...they say allot. Wipe the surface of components. If they are covered in black dirt (metal) then you should probably think about some maintenence

Why would you want the same contaminated slop running through your trans gears?

Wait till the powdery slop builds up in your trans cooler and your trans doesnt cool efficiently anymore.

Be proactive not reactive