MK3 1.8 Autobox jerking since fluid change

I have a MK3 golf 1.8 auto with ADZ engine. The oil cooler failed and contaminated the ATF fluid with water. I have replaced this, drained the fluid, dropped the sump, replaced filter and cleaned all the crap out. When I first refilled with new fluid, I removed the plug in the sump which I thought must be a fluid level due to the height of the pipe inside the sump. Box was rough and sometimes wouldnt pick up 1st gear, in fact it kept snatching and releasing. I added a further half litre of fluid and the drive was much improved. This morning, went to pull away, and again the car was snatching to get 1st gear. Any ideas why this would be, as there is no dipstick how do I know how much fluid to put in. Filler pipe clearly states Dexron Fluid, it has a red plug that you remove for filling purposes Sad

Hello, Sounds low. In fact water is a far better contaminant than engine oil. I would sujest a phone call to a local transmission repair shop. They will have all the latest information, and if you ask nicely may help you. Be prepared however to pay for a professional flush. I work with a lot of hydraulic systems, and due to the design of this hydraulic transmission doubt that it was possible to get "all the crap" out . The major shops should have a special machine they hook up wich alows them to run your transmission under load. Some water is absorbed by the fluid , as well as a lot of water contaminated fluid is inside the torque converter. Their machine changes, filters, and analises your entire fluid contents. It takes at least an hour. I do not know where you live but it is minus 5 C where I am . If you were here, you would be lucky if it would shift at all. Allan