Gearbox ID

[grannyknot]

Hi Chris,

That is interesting. Your photo's clearly show brass teeth on the rings on the fifth gear synchros. Like I mentioned, I have read about fibre synchros on the fifth somewhere, but never seen one or known anyone who has. It could be just a myth or in other Nissan models.

How did you go with your transmission rebuild?

Thanks for posting

Chas

Chas, as you might remember, I was rebuilding my perfectly working close ratio 5 spd tranny because of a buzzing/rattling sound from the stickshift, after rebuilding with new bushings and syncros the same buzzing/rattling is still there and driving me crazy. I rebuilt the spare 5 spd at the same time so I'm going to try the second one and see if that fixes it. I wonder if it could be a something with the universal joints? The sound and most of the vibration disappears when I grab the shift knob. ???

[Mark Maras]

I had a vibration in my 71 that I could feel in the stick but I pretty much ignored it because I was trying to find the 800 lb. bumblebee that came around at 80 mph +. it was so loud it would drown out my AM radio. I went through the trans & linkage, then replaced all six u-joints. b-bee was still there. Next step was to take the drive shaft to have it balanced. as it turned out the shaft was bent ever so slightly.They retubed the drive shaft, put in Spicer u-joints, & gave me a lecture on why I should never buy anything but the best. I couldn't stop grinning at the difference. It not only eliminated the stick & the b-bee vibration, but a few more that I assumed were normal. Check the d-shaft balance & go from there.

[EuroDat]

I would agree with Mark. Sounds more like a drive shaft problem. Is the rattle speed related or engine revs? If its speed then its a strong possability its in the drive shaft. My tranny makes noise in fifth gear. Forth is so quiet compared to fifth. You don't want to know how much I spent on all the bearings, sleeve and stuff, its a lot better, but still not good.

I changed my uni-joints in the drive shaft and the two half shafts. I purchased Nissan uni-joints and two sets of circlips for the drive shaft. The front uni needed 2.00 circlips on the yoke and 2.04 on the drive shaft. The rear used 2.02 all round. Make sure you use the same for opposite side cups otherwise you will set the shaft off centre.

0.04mm doesn't sound much, but Nissan thought it was and I think its important to center the drive shaft as much as possible.

I used Moog uni-joints on the two half shafts.

If the uni-joints don't fix it, then checking the balance would be my next step. You can check if its bent by jacking one wheel off the ground and hold a screwdriver so it just touches the centee section of the shaft. With the tranny in neatral, get someone to rotate the wheel by hand. If it has any runout its not a good sign.

Chas

Edited May 3, 2014 by EuroDat

[grannyknot]

Thanks guys, the buzz/rattling is speed related, I'll pull the DS and start there.

Chris

[Casey_z]

Just saying to be sure you have done it.

Shifter bushings?

Casey

Thanks guys, the buzz/rattling is speed related, I'll pull the DS and start there.

Chris

Edited May 3, 2014 by Casey_z

[grannyknot]

Casey, yes all three bushings were replaced.

I've been doing a bit of research on U joints and I have come across the advice to use only Nissan U joints. Can anyone comment on why they are better or different?

Thanks,

Chris

[EuroDat]

Hi Chris, The Nissan OEM's are better. In quality of metal and craftmanship maybe no better than top quality aftermarket, but you have the possibility to adjust the amount of end clearance with the different size circlips. I used Nissan on my drive shaft and also purchased two full sets of circlips. See post #15 in this thread.

They come in 4 sizes 2.00 through to 2.06mm. Doesn't sound like much but 0.06mm can be a cause for that irritating gear stick chatter.

Remember the tailshaft has the potential to be one of the fastest rotating items in the drivetrain, turning up to 120% of engine speed in 5th gear.

Chas

Edited May 4, 2014 by EuroDat