POPS OUT OF 5TH GEAR

[Zfreak]

Here's the scenario...Driving down the highway...Speed 65 MPH...5th Gear...All of a sudden the trans pops into neutral. I mean the stick actually popped back into the neutral position. I put it back into 5th...No problem...About 5 minutes later if happened again. It seems to happen on the thottle more than off. The car is a 1977 280Z. Any ideas?

[Mike kZ]

Sounds like a bad sincro. I had a trany that did that in third, as long as I had the gas peddle down it was fine, but when I let up it would pop out.

[Guest Anonymous]

I have a 77 620 truck with a Z 5spd and it does the same thing, I have been told it's just a matter of time before I lose 5th gear all together. I guess it would be time for a Hybrid 620 truck. 2400lbs base weight with a 300 horse V8 and 700R4 trans should get down the road pretty well.

[blueovalz]

The small teeth that are used to engage the gears are most likely worn beyond the normal amount of "flat" engagement area. When they become tappered all the way down to the base, they will do this. Also, the sliding splined cylinder that engages these small teeth can get worn too. These two pieces only overlap about 1/4" or less to egage the gears, so there is not much room for a positive engagement, especially when the wear takes hold. And the popping out of gear accelerates the wear to the point that this gear will become unusable.

[Guest Anonymous]

the "dog " or "clutch" teeth you are referring to are responsible for engagement, but do not keep the syncro hub ( the splined sliding thing ) engaged. There are three keys per syncro that act as a detent that " lock" the sycro hun onto the "dog" teeth.