Hello all, I am a little stuck in diagnosing my transmission flaring issue and I thought I could run it past all of you and hopefully get some suggestions of where to look next. I just bought the car off the original owner. It looks 100% like new and has been very well maintained. That said, The previous owner said that about 15 years ago the automatic transmission has flaring quite a bit between 2nd and 3rd. Being that we live in a small town without a Mercedes dealer, the local trans shops were not able to diagnose it. A couple shops thought it might be the transmission modulator. Anyway, the car has been doing this for 15 years and the trans fluid looks like red cool aid and has no burnt smell at all. Here are the things I have read about to check and have performed... 1. Trans modulator holds good vacuum testing with banjo fitting disconnected at intake manifold (plus it does not leak trans fluid when disconnected at trans) 2.With engine running, there is very good vacuum at the disconnected banjo fitting at the trans.
3. When driving the car with the vacuum banjo bolt at trans disconnected there is no difference in shifting.
This is the part that I don't understand. Can the trans modulator still be bad even if the diaphragm holds vacuum? The fact that it makes no difference if it is connected or not leads me to believe that it is the modulator. Does anyone agree? As far as I can tell, there is no adjustment I can make that will adjust the amount of flaring between gears (Like the diesel version). Any suggestions would be greatly appreciated. Thanks a lot for your time.
-Spencer