Ford Mustang GT common problems: what to check before you buy
Credov's researched list of the 5 faults the Ford Mustang GT is known for (2015–2023), 5 of them serious or costly. Each one says what to look for when you check the car, so you can spot it before you buy. Not every car has these faults: they are the ones worth checking on this model.
Known problems on the Ford Mustang GT
5R55S auto slips, loses reverse
Costly if missed
2005–2010 · petrol · Gearbox
What to look for: Select reverse from cold and warm, checking for a delay, clunk or no drive, and feel for slip on an overtake.
Why it matters: This gearbox has no dipstick, so the fluid is rarely checked or changed, and once the servo bore wears, the usual fix is a rebuild with the bore sleeved or a replacement gearbox.
What to look for: From cold, try every gear including reverse and feel for notchiness, a crunch, or a gear that refuses.
Why it matters: Owners traced this to a mix of clutch drag, a weak factory shifter mounting and tired fluid, and grinding on every shift can also mean worn synchros needing a gearbox rebuild.
What to look for: On the drive, make a firm 2-3 change at higher revs and feel for 3rd blocking or refusing to go in.
Why it matters: A gearbox that locks out of gear at speed can momentarily leave the driver without the gear they expect, and fixes reported range from a shifter bracket and fresh fluid to a clutch replacement or a full rebuild if synchros are worn.
What to look for: Come to a stop gently several times and feel for a clunk on the low-speed downshifts.
Why it matters: Ford's and specialists' diagnoses point to clutch drum sleeve movement, valve body wear and cross-leaks, and fixes range from a software update and relearn to a valve body or a full rebuild, so unresolved harsh shifting is worth pricing in.
Got a question about a Ford Mustang GT? Ask Credov: a noise, a warning light, a part or how to fix it.
Also check on every car
On top of the faults above, every Credov inspection covers the basics: fuel smell, leaks or filler rust, engine oil leaks, power steering fluid leak, drive belt cracks or squeal, rust underneath: chassis and mounts, engine mounts, engine oil level and colour, coolant level, colour and leaks, head gasket failure signs, cold start: rattle, knock or smoke, rough or hunting idle, engine running hot on gauge, gearbox or diff oil leak, swapped gearbox without lvv and more.
Researched by Credov from manufacturer recalls and service bulletins, owner reports and workshop sources. Repair prices are typical ranges, not quotes. See also fault codes and repair costs.