Suzuki: Suzuki Autozam MKII, wheel bearings, suzuki samurai

Question
The transmission on my daughters cars slips and bucks mediately on takeoff. A local transmission expert said it was jumping out of first gear and the bearings were going. I believe him because I can hear the grinding and there is nothing wrong with the wheel bearings.  He said my best option was to replace the transmission or he could repair it but it would cost a lot. I have found a replacement transmission. I have replaced the tranny on twoo other cars but I feel a bit insecure with this one since there is no manual available.
The car was built by Suzuki but sold by Mazda as a Mazda Carol, Autozam MKII. It has an F6A motor and tranny for AA6PA Mazda.
My question is. do you have any advice for me should I undertake the replacement myself?  Or do you know where I might get a manual. There are all manner of manuals for other similar cars but not this one. the plate specs show
Autozam
Model E-AA6PA
Paint TC
Vehicle ID NO. AA6PA-213949
(A002)
The mechanic says he'll do the switch for 400 but my daughter says she can't afford it so I will pay or do it myself.

Answer
The switch is the cleanest simplest way.
Anything can be rebuilt, but unless the vehicle is retained for another 5 to 10 years, it's not usually as financially advantageous.  Make certain that the transmission has all the oil seals replaced - a great many (perhaps most) transmission problems are caused by leakage and insufficient lubricant.
I live in the Colorado mountains in the US. That vehicle has, to the best of my knowledge never been imported here, and I don't know much specific about it - my field of expertise is Suzuki Samurai
Sorry I can't be of more assistance.