Seat Cordoba jumps out of gear

This from another forum might be you cause ,


This is why you should check your transmission lube frequently. A common 5th gear failure problem.


I wish the search function on this forum didn't draw such excessive vacuum. It seems like I've answered this 2 or 3 time.
You should check the lube in your next transmission more frequently.

Here's what happened to you:

Your transmission was low on lube. Because of the shape and design of the transmission, the 5th gear housing goes dry first when the lube is low. After an extended trip at high speeds in 5th gear, with the lube level so low that 5th gear was running dry, the unlubricated bearings in the 5th gear housing heated up very hot. Once the metal in the 5th gear section got hot enough, it started to anneal and soften. The synchronizer ring for 5th gear gets soft first, and when it softens, the thing will slowly work it's way out of 5th gear.

Once you put it back in fifth, stuff continued to heat up, and the next softest piece of metal in there is the inner splines on the driven gear of the 5th gear set. Those got soft enough to strip out, and 5th is now neutral.

Basically, you need to rebuild the transmission, or to install a used unit as a replacement.

If you decide to rebuild the transmission, here's the minimum parts you need:

- New synchronizer for 5th gear
- New 5th gear gear set (both gears)
- New ring and pinion set

You'll also need to have everything checked for wear and damage. I'd replace all the synchronizers while you have it opened, and replace all the bearings as well. Check carefully for damage to gear faces and bearing surfaces on the input shaft. You have metal filings from the stripped splines floating around in the oil. Those metal filings can score and grind things that are supposed to be smooth and flat.

You've experienced one of the classic failure modes for this transmission. To avoid this in the future you can do two things.

First, check the transmission lube frequently. I check mine at every oil change. It's something to do while the oil is draining from the pan. If I find losses, I search for leaks and check it more frequently.