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My Civic has started delaying upshifting, won't shift up until it gets to above 3,000 rpm, sometimes more like 3,500. Started very suddenly immediately after I replace a heater hose on the tranny side of the head. Don't know if it's a coincidence or not. I and a mechanic have looked for a loose connection or something in the area of the heater hose, but have found nothing out of place.

I tried to adjust the kickback cable and so did a mechanic and while it helped a bit, it didn't solve the problem. Now the mechanic says I need a new tranny.

It's low mileage, <130,000, and the engine runs like a top, uses zero oil. Rest of the car in nice shape.

What do you think? Does it need a new tranny, or is there a simpler, cheaper repair? If it needs a tranny, how to get a good working one at a reasonable price? What are my options here?