Help
I have a 96 S320 140.000 miles
8 weeks ago the transmission started to slip. I had the car towed to a local indy for repair, that was 5 weeks ago. I was told the transmission has been in and out about 6 times by 2 different shops (my shop had it taken to another shop after they could not repair it). Now I was told the trouble is that the transmission locks up when going into reverse. Whats so different about this transmission that 2 shops are having trouble.

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2009 CLS550 55,000
2004 ML350 144,000
2004 X5 95,000
2002 X5 165,000
1996 320S 155,000 (sold)
1991 190E 192,000 (sold)
1989 300SE 160,00 (sold)
1984 300D 210,000 owned since 85, (sold)
1984 300SD 160,000 (sold)