What is the difference between a kia transmissions and a honda civic transmission?

What is the difference between a kia transmission that has to be replaced in 6 months and a honda civic transmission that can last for 350K miles?

Quality of parts. Kia is cheaply made.

Umm don't flatter that honda. Drive it like you stole it and it turns to the same poop. Those also arent ford transmissions lol, ford doesn't usually use 12mm fasteners, they have 13mm. In fact you have it the other way around, the big 3 farm out their small platform power plants to the import companies.
think of it like this, a couple companies split the cost of research, tooling, etc to bring the product to you cheaper. If the company had to foot the whole bill for launching a new platform, not model, the price can run up to a billion before 1 single vehicle is sold. This means they have to charge more per unit to turn a profit.
most modern vehicles are designed to need a complete restoration in roughly 11 to 14 yrs with normal use, and the companies obsolete the parts long before then. There goal is to get them to be more trouble free the first 5-7 yrs, then go away. This forces a traffic jam in the car chain and increases sales. More lower income people are forced to buy new or near new cars and replace them more often. Those cars have to come from somewhere. They are tradeins and lease returns. The average joe trades his new car off faster so he doesn't get caught with the sinking value of the car.
when keeping up with the jones's life cost a little more. I remember my grandpa buying new and keeping them forever. Face it a 40year old rambler is probably gonna be in better shape than a 40year old honda

Year and miles on the KIA would help also depends on the maintenance on the cars and if it was abused or not. The year on the civic also since Honda had transmission problems from 98-07

I have not heard of any 'tie' between Honda and Kia, but both are top quality products with great reputations.

Dr Bearface. You really don't have a clue do you? Kia are owned by Hyundai, Not Ford.