I have no idea what brands of automotive parts cleaning solution are available in Armenia but any standard solution should be fine – it doesn’t require anything special. Just make sure not to put the clutch plates in it and I would also avoid flushing it through the needle roller bearings in the epicyclic geartrain assembly.

The most critical thing is to have your torque converter re-manufactured otherwise there is a strong risk of you cross-contaminating your nice clean transmission fluid with the debris that previously got trapped in the torque converter. As failure of the TC lock-up clutch is extremely common in the 5L40-E this will also be replaced as part of the converter’s re-manufacturing process.

Phil