My MK7 Fiesta has over 80k mileage and I have taken it to two garages so far. When I first start driving my gear box is a dream and then maybe 12 plus miles start to become stiff.

I printed out the options I found on here ie copper grease in the rods and bushes in the compartment under the front of the car. This has been done, no real difference to the gears. So I ask the garage to check the rods and bushes, one suggestion stats that the bushes expand and this causes the problem.  Garage had never heard of this and as for the part being £33 they disagreed with that as well. They are suggesting that the gear box is the fault and I need a new one. I live in Dagenham and I will have to get rid of my car rather than get a new gear box. I just want someone who actually knows mk7 fiesta that can help me. I mean the bushes idea does make sense to me more than anything, ie gears good at first and then tighten up. The mechanic said the bushes are normally £200 each and there are two.

Any help would be good I love my car and it is in excellent condition apart from this issue

When was the gearbox oil last done?

Are you sure it's not something to do with the clutch or the master or slave cylinders?

i had a mk 6.5 which had the same symptoms as you mentioned. gears were great until it got warmed up after 10-15 minutes or so and then they went really stiff. on mine it ended up being the rods inside the gear box which was failing. 

If you think that it's the bushes, Spray them with silcone spray. Screwfix sell it.

The two mechanics I went to didn't help at all. There is a cover under the front of the car which the RAC man took off and cover everything in copper gear. This did help the gears loosen up, but it is when it gets warm that they tighten up. In answer to the gear box oil I have had the car three years and never changed it. I take it isn't anything that ford do on their services?  I love my car but don't know what to do, so phoned a local gear box specialist who said that the zetecs have one of the best gearboxes in it and he can see how some bushes would cause a problem.  I am going print out I found on this site and let him test drive the car.

Firstly, sorry to hear about your problem.  I'm no mechanic and have had no experience of this issue, but it does sound a bit extreme to replace the entire gearbox if it works fine at least part of the time.  How many miles are on the car?

The earlier Fiesta but may solve your problem.