It happens at 2000 RPM after it shifts once. One shift would be into 3rd as it takes off in 2nd. I ordered 2 bolts this morning from the local MB dealer. $7.50 for 2! I'll try the 12 point socket over the old bolt next Tuesday. I dont think there's enough room to grind 2 flats on the bolt. Thought about heat but there's the rubber boot that's too close. I let it soak 30 min with PB blaster. I will do this bolt 1st because the axle will be flush with the flange to the differential. We initially thought the flange being loose and slightly at an angle was binding up the bolt so I reinstalled 2 bolts to realign the flange but to no avail! Thanks all for the insights! The saga continues. So as to not have a completely wasted day, I did adjust the parking brake shoes and replaced the original woven fuel line from the tank to the fuel pump!

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81 300CD (sold) 1972 280 SEL 4.5 (sold) 1966 250 S 4 spd (sold) 1974 450 SL (sold) 86 BMW 325ES (sold), 1973 280C (sold) 1988 300 SE.