Is it normal for BMW E46 M43TUB19 to have a small 'thud' sound everytime the reverse gear is engage?

Is it true that ATF in a BMW has Lifetime Warranty and need not be replace?Is it normal for BMW E46 M43TUB19 to have a small 'thud' sound everytime the reverse gear is engage?If it is a small noise, it is likely normal. I expect a small nudge and accompanying sound each time I shift an automatic transmission from Park to Drive or Reverse. If it feels or sounds particularly harsh, however, I would have a trustworthy mechanic feel / hear this and take their recommendation.



Regarding the "Lifetime Warranty" on the transmission fluid, my understanding is that it does not mean that the fluid does not need to be changed indefinitely. Instead, BMW is implying that you shouldn't need to change the fluid within a reasonably long period of time, vis-a-vis the "lifetime" of a normal ownership of a car. Once again, I would recommend obtaining the advice of an experienced (and trustworthy) BMW mechanic.Is it normal for BMW E46 M43TUB19 to have a small 'thud' sound everytime the reverse gear is engage?it depends is it when you first shift or while you are moving backwards? If it is when you are moving backwards is it regular (like if you keep it a a steady RPM does it happen at regular intervals) or irregular. if it is when you first shift that is normal (that is changing gears) otherwise if it is at regular intervals i would check the clutch and tranny.