I have a 2005 Mazda 6 Diesel Estate, last week I was forced into a high kerb at about 40mph. This damaged my cv joint and driveshaft. The cars is now jumping out of 5th gear? Any idea what's happened. I have had the cv joint and driveshaft replaced.

Many Thanks

 

Time for a new gearbox or a rebuild.

 

Was the car in 5th gear when it hit the curb? The possibilities are a broken cable end bushing not allowing enough travel to lock 5th in. ( Not likely not as it would probably jump out of another gear also since the same cable controls another gear) Although the cable would be pushing on the opposite side of the cable bushing sooo. Depends on how it broke. The spring in the hub sleeve that holds the dogs popped out of a dog. ( partial disasembly and trans removal required). A damaged 5th gear hub sleeve/synchro. The cable end bushings would be the first thing I would check. Just for general info I can tell you that the most common cause of a trans popping out of 5th is a worn out hub sleeve and fork due to the driver resting his/her hand on the shifter while driving. The hub is turning as your driving and that eats them slowly until they don't have enough reach to fully engage 5th.