Ever since I bought my GTA, fifth gear has been "missing". Moving the shifter into the fifth gear position takes no resistance, theres no grinding even without using the clutch, just nothing. All the other gears work fine, even reverse. Any ideas what could be causing this?

 

Broken shift fork, broken or missing roll pin for it, trashed fifth gear

 

Can I check anything externally? Or will I have to open it up to look at it?

 

It's all internal. Nothing you can see from outside.

 

MY guess would be that the snap ring popped off or broke. That is exactly how mine acted when the snap ring popped out.

The trany has to be taken apart to get to it.

You can see in the below pic that the snap ring came out of its grove and the 5th gear was allowed to slide back and no longer engagues the main shaft.

See pic below:

 

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