I have recently noticed a couple of problems with the transmission in my 300SD. I was told that the transmission was rebuilt before I got it, and I have changed the fluid and filter a couple times in the 3.5 years I have had it. It mostly worked fine until the last few months, other than sometimes taking a long time to go into gear when it was really cold outside. Now, the first problem is that it won't go into gear at idle anymore, you have to tap the accelerator to get it to move, then it goes into gear with a thud and will start to move. It also sometimes slips on the 2-3 shift, and other times shift firmly, and this doesn't seem to depend on throttle position. Last, it doesn't always go into park when you stop and move the shifter into park, rather if its on enough slope for it to move it will roll back and make a loud banging noise until you step on the brake then it will eventually stay. Any ideas how to fix any of this?