Garage Cabinets, Garage Storage, and Garage Organization

Hi i have a 2 door E 1996 looks stunning drives great other then gearbox issues.
The car drives well in all forward gears but struggles to go into reverse gear when warm or hot.....
When in reverse she shudders a lot and seems to be lacking in power (struggles to reverse up hill or over curb... sometimes even with no gradient)

Does any one have a clue what is wrong with ...experienced similar...know what i can do about it?
Changing the gearbox is an option but i really hate to loose the original gearbox but if that is sensible i will consider.... repair is preferred but i want it to be back to perfect..... who to go to? quality of parts? If you were to go get an engine rebuild i understand this is commonly done with inferior parts....is this the same for gearboxes??

Any advise recommendations would be much appreciated...

Thanks
Aman
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