Ask an expert

Hi - my son was driving his WRX Turbo when it was hard to change gear then started making a terrible banging noise. We got the mechanic to pick it up and he said it sounded like the big end. I explained the engine had been done recently but he said they go all the time on turbos. I did tell him it was hard to change gear just before it happened but he said that sound is typical of the engine so the engine had to come out. To cut a long story short, he found it hard to diagnose, got an outside opinion and came up with it needed a new gear box. He got a performance gear box sent up from Ashburton but it was the wrong one. In the end my son and I just said put a normal gear box in (it was about 5 weeks by this time) as he said the performance gear box was hard to come by. We just needed the car on the road. The final bill was $3,600 and I had a quote from another mechanic to say a normal gear box fitted would be $1,700. My son is not financial (and nor am I - single Mum) and we wondered are we responsible for them not being able to diagnose the problem. We expected to pay more than $1,700 for the mucking around but $3,600 seems excessive - we had to pay for gaskets, seals, etc. when the engine came out which ended up being totally unnecessary. I would appreciate your advice - thank you.

I can understand from a mechanics point of view that some problems are difficult to diagnose and sometimes different faults display very similar noises and vehicle behaviour - so it is easy to be misled in believing the fault is with the wrong component.

However, the mechanic has misdiagnosed in this case and he should be doing everything possible to reduce the cost to you for his error.

You should request a breakdown of the invoice to see how much he has charged for his error. It is possible that the gearbox costs a lot more than $1700 and then you also need to consider the labour to fit the transmission.

Thanks for your prompt response. I have a breakdown of the invoice and the gearbox only cost $625 (+GST). Of course it needed the differential done too and oil and stuff but another quote I got said it would take 5-8 hours to do the gearbox. All up our job took 22 hours which would have been unnecessary had they not taken the engine out. Is it so hard to diagnose a gearbox (especially as we had mentioned it was hard to change gear just before the noise). Can we do anything legally or do we just have to pay the bill and move on. We haven't paid the total bill yet as we didn't have enough money as it was way more expensive than we initially thought.

Can you please e-mail the invoice to aatech@aa.co.nz and we will advise accordingly.

I will email it tomorrow as I don't have access to a scanner today. Really appreciate your advice.