While driving my (automatic transmission) 1970 280SL it suddenly popped from 4th gear to neutral; it would then only drive in reverse or 2nd gear---no upshift to 3rd or 4th. Shop tells me I need a new transmission ($4200. from M/B); since this is not a transmission shop, I told them not to do anything and I would take it to a tranmission shop to confirm their diagnosis. Obviously, I'm looking for alternatives to spending this much money. If I go for a rebuilt, I see 3 names that are coming up: Adsit in Indiana, Peter Schmid in Calif., and Sun Valley in Calif. (I'm in N.Y.). Has anyone had any experiences with any one of these outfits? Any one better than the other, or should I go for the best price? Am I jumping the gun in assuming that my problem can only be remedied by a rebulid instead of something else (a friend suggested I may only need a torque converter[?})? Any suggestions? As always, thanks.