That is my concern now. $1200 gambling. Hmmm... think think think.
sounds to me like you have an interferance issue , this has to do with timing OR someone dropped something into the engine and that may be the noise you are hearing.. i lean more towards interference. Idoubt its the torque converter of which its main purpose is the transfer of engine power smoothly to the transmission .I am in USA. I bought a 2005 RR L322 off Copart auction for cheap. It was $375 but with the broker fee, copart fee, all kinds of fees, it ended up $1436. It has 125K mileage on it. It has a BMW M62 4.4L engine with a 5HP24 transmission as you all know.
So, troubleshooting began. There is no check engine light on dash or scanned (using a Launch X431) on the engine and transmission modules. Then I noticed that the starter was removed and in the trunk. I tested the starter. It was spinning. Then I tried to hand-crank the engine after removing the fan clutch (special tool but cheap but still was not easy but I did it). Engine did not turn. Conclusion was that they removed the starter and found it working and concluded the engine has seized and stopped there. Then I removed the spark plugs (and spraying WD40 which might not have helped) and wiggled the crankshaft back and forth by brutal force and eventually got it free. (However, I did notice a lot of metal cracking noise from either engine or transmission or torque converter.) After a few dozens turn by hand cranking and engine finally turns freely (clockwise). Then I put back all spark plugs and the starter (****, that was tight space there, the shield did not help either), I was available to start the engine but I continued to hear metal cracking noise randomly. At that time, I was able to shift to D and R. The car moved. I did not take it out for a drive around thou. I did notice when I shifted, the engine speed dropped down a lot and sometimes died. Also, I continued to hear metal noise while I revved up the engine.
Next day, I decided to change the engine oil and transmission filter + oil because I wanted to see if there is any metal pieces or shaving in the pans. Engine oil was black anyway. No shaving in the engine oil pan. But there is quite a lot of metal shavings on the magnets and around in the transmission pan:
View attachment 283385
Moving on, I put everything back and started the engine. Oil changes did not help and I continued to hear metal cracking noise and now the engine seems to die because of something in the torque converter dragging it or locking it up. Whole time there was no CEL. Not knowing what I could do next, I have stopped here.
I have a feeling the torque converter has broken fins on its turbine and initially locked up the engine. I, by brutal force, broke it free and the loose pieces continued to damage inside while I revved up the engine, to the extent that now the engine could not keep idling and has still a lot of metal cracking noise when I run it. What should I do next? The metal shavings (or pieces) should have gone into the transmission by now and the torque converter need to be replaced and the transmission needs to be rebuilt or replaced?
I am a DIYer and quite equipped and enjoy bringing this car back to life. If this is kept under $1500 USD, it might still be worth it. Afterall, the engine has a lot of oil leaks. I believe the valve cover gasket, PCV, chain guide cover gasket and God knows what still need to be repaired after this.
Or just sell the car for parts?