The most commonly discussed Achilles heel to the Fiesta XR4/ST150 is the IB5 transmission. The gearbox doesn’t randomly explode, but has one significant weakness in addition to the “usual” front-wheel-drive hot-hatch gearbox fragility.
Ignore the differential failures caused by one-wheel burnout antics the real problem is the factory fitted differential bearings. The only solution is to replace these bearings with a metal caged alternative.
I wanted to see if there were cheaper options so I started with the two Ford Part Numbers and did some Googling. The IB5 differential is supported by two different sized bearings of 65mm and 71mm outside diameter.
The 65mm Bearing:
– Ford Part Numbers: 1677043, 1063385 or 5092541
These cross reference to aftermarket codes:
The 71mm Bearing:
– Ford Part Number: 1070470
This bearing cross references to:
Sourcing for Less $$
With the part numbers in hand I tried the usual local bearing suppliers and found that it wasn’t easy to get a local (within Australia) source that carried both bearings at a good price. It was back to Google and that brought me to Henderson Bearings in the UK.
Henderson Bearings have an easy to use website that lists the two bearings needed at great pricing. Add in the Royal Mail or UPS delivery options and it’s possible to have a set of differential bearings delivered to your door from about AUD80 (Royal Mail)!
Here are the direct links:
I have no affiliation with Henderson Bearings, and using the Part Numbers above you can find these bearings from many suppliers at a variety of prices.