I had an interesting problem develop last week. My audi 100 (K reg) started overheating & when I examined the coolant in the overflow box it was a brown colour and the texture of liquid mud. Thinking it was rust from the radiator I flushed it all out & re-filled with anti-freeze.
2 days later the auto started slipping & jerking so I checked the auto fluid level to find the fluid was a brown liquid mud type substance and had gone up by a cm on the dipstick.
You've gussed it, the auto-fluid is mixing with the radiator water - how? Well, the auto fluid is cooled by running the pipes through the radiator, and a small split has resulted in the mixing of the two. I now need a new radiator & potentially a new auto-box: unless the box can be cleaned of the liquid mud & got working again.
I beleive this is the design on all Audi's with auto transmisson - so watch out it could be an expensive repair. Audi main dealer quoted 2800 pounds for a new auto box - car is only worth
1500 pounds. Anyone know if there is a flushing fluid for an auto-box which could clean it out before new auto-fluid is put in? Any guidance is appreciated Mike