Manual Transmission problems of the 2005 Lotus Elise

Manual transmission popped unexpectedly out of 5th gear during hard driving causing driver to select wrong gear in attempt to regain control of vehicle. The placing of the transmission into 3rd gear by mistake led to catastrophic over-revving of the engine with engine failure (total loss). Dealer had been advised regarding the popping out of gear prior to the fatal event and was unable to find problem. The engine was replace and in spite of dealer assessment the problem has continued. The problem now has worsened to grinding of the gears on simple driving. A local transmission specialist has advised defective transmission. The manufacturer has been advised, but reports to me that they do not believe there is a problem. Their engineers cannot conceivable think of a way the gearbox /transmission can "pop" out of gear if properly placed into the gear. The problem has been observed by two other independent drivers who have had the problem occur with their use of the vehicle. I as the owner have purchased another transmission to replace the defective transmission. The manufacturer has been notified and has reported no interest in seeing the defective part, nor any willingness to participate in fixing the issue. Issues remain: manufacturer unwilling to investigate the complaint as well as recognize that the problem could exist. Safety concern remains for those not expecting the sudden loss of control which can lead to an accident or as in my case the destruction of the engine.

1) at first 1st to 2nd up shift and 3rd to 2nd down shift was grinding at about 5000 rpm. Shifting progressively got worse shifting from 1st to 2nd and 3rd to 2nd. Now 3rd to 2nd down shifting grinds at every rpm and 1st to 2nd shift is very difficult. Diagnosed by mechnanic as synhro failure. 2) 2nd gear synchro failure. Can't upshift well and down shifting from 3rd to 2nd grinds gear and destroys gear. Unsafe when you can't get into gear. 3) Lotus USA and the dealership autostrada USA have denied warranty claim. They won't fix the transmission. My car is still under bumper to bumper warranty.