Driveshaft slack/backlash - How much is normal?

[jy116]

Problem: When i step on the gas and let off abruptly consecutively a few times [in gear], i can hear a slight, muffled clicking noise... like play in the driveshaft.

Checking: I jacked up and got under the rear and rotated the driveshaft by hand [with the e-brake off] and theres a little play on the driveshaft b4 the wheels start turning. Maybe like ~5 degrees of rotating b4 the wheel moves.

I looked at the FSM under PD [propeller shaft +diff] and says "runoff should not exceed 6mm". Seems like this refers to the driveshaft longitudinal play [lengthwise], so Im not sure if that slight slack [backlash?] is a real problem or if its normal.

Specific Info:
*I got a used VLSD, supposedly JDM, 6 bolt flanges, been on for ~2k miles, didnt change the oil when I got it cuz my frend put it on b4 I could do it. I know its not too major cuz the viscous diff itself is sealed with its own lubricating silicone crap. Dont thnk the pinion gears would wear after ~30km [in JDM land] and 2k miles...
*I had a auto to 5spd swap done, the driveshaft is half from MT and the other half is from the orig AT driveshaft.
*Car drives fine, just worried now cuz I signed up for drift practice on March 19 [see USA thread, "SCCA Drift Practice"] and dont want to break anything or forfeit my $75 spot!

Some one who drives hard/drifts their s13 wana check this to see if its normal? U can rotate ur tires/change ur diff fluid while ur at it?! ;]

[citizen]

the back lash is in your diferential. mine has a few degrees of play in it as well (jdm 5 bolt vlsd). i wouldnt worry about it (ive been beating the shit out of mine for 12,000 miles)

[The Hamsterball]

Yeah, I 2nd that the noise is from your differential.

Sometimes the noise is much much worse, depending on where it is from in the differential. On my old open differential, it used to make a LOUD *CLUNK* noise when shifting, letting off the gas (even slowly), and if you did the gas-off-gas-off-gas-off test it would make the noise worse.

The output shafts on that differential had a LOT of play (they're not supposed to have play at all) and that was what caused the noise. It was a combination of normal noise and output shaft hitting themselves into position before turning.


On my new VLSD it doesn't make noises easily, but I still hear the same noise you are describing. It's a slight *clunk* or *thump* noise if you shift and engage too late or too early (in mis-matched engine speed/RPM). It will make the same noise as the old diff if I do that gas-off-gas-off test, but not as LOUD as the old differential.

I've always gotten scared of this noise as well, but every 240SX (S13) i've driven has the noise, so that helps.

You could always use a pen to test out the runout spec if you wish.

[jy116]

cool... lookin forward to a good day of safe, legal drifting goodness... >:]

[sideviewcivic]

if you install subframe spacers/collars the noise and vibrations are increased indefinately. Not a bad thing IMO. I was bored and saw these http://www.bulletproofautomotive.com/catalog-detail.php?ID=2157 and im curious as if something of that design would benefit our cars