Tranny issues

[Guest DatsuNoob]

I've noticed that sometimes (not all the time) when I'm driving and I shift from 2nd to 3rd or from 3rd to 4th, my transmission will make a very short grind before it goes into gear. It doesn't sound like anything major, but I know it's not normal, what could be causing this?

[datsun dreamer]

I had that issue myself and after troubleshooting the situation i found that it was my slave cylynder starting to leak causing air to get into the systym and not engaging into gear smoothly.

[datzenmike]

Yup. If the clutch does not fully disengage the transmission syncros are forced to work much, much harder to speed up/ slow down the mating gears so that they don't grind. The sound you are hearing are the syncros working overtime.

 

Place the tranny in neutral, clutch out. Put the clutch in (count to four to give the spinning gears a chance to stop spinning) and try to put in reverse with light pressure. If there is constant grinding, the clutch is not disengaging. If double clutching cures this, the hydraulic system is at fault.

 

Besides air in the clutch m/c or slave cylinder, the clutch disc or pressure plate itself may be damaged or warped and rubbing together.

[datsun dreamer]

I got real lucky, i just replaced the slave cylynder and the problem was gone it only cost @ 35 dollars for parts, i did replace it as soon as i heard it i think if i had waited it could have damaged alot in the tranny.

[datzenmike]

That's good news! I drove my original 620 tranny for years wondering why you had to grind into 2nd down-shifting, and it was stiff when fast up-shifted. I always drove it lightly with 'coffee break' shifts and it was fine. I later found the slave was worn out but partly working. I know if I 'performance' shifted it, it wouldn't have lasted. I drove it for years after that until it finally lost 5th and then 2nd and I replaced it.