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How To Tell Visually If I Have A Mechanical Diff.

rad100
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rad100 Grand Master

rad100

Posted
Posted

hey,

was wondering how to tell if i have a mechanical 2way diff buy looking at the diff center...

when i turn the wheels back and forth they both spin, but this also happens on my stock diff.

how do i tell if i take the diff housing off?

cheers

GTSBoy Grand Master

GTSBoy

Posted
Posted

In the stock diff there's a cartridge right in the middle of the centre, between the internal gears. That's the viscous cartridge and is not there on mechanical diffs.

Now, if you look into a mechanical diff, you will see the end of a pin sitting in a pair of ramps. Look at the images in here http://www.google.com.au/search?tbm=isch&hl=en&source=hp&biw=1582&bih=863&q=2+way+diff+ramp&gbv=2&oq=2+way+diff+ramp&aq=f&aqi=&aql=&gs_sm=e&gs_upl=1228l8730l0l9276l24l21l2l8l8l0l262l1695l3.2.5l11l0

and see what I mean. 2 way has even ramps (same both sides. 1.5 way and 1 way are biased (ie, steeper ramp on one side than the other.)

GTSBoy Grand Master

GTSBoy

Posted
Posted (edited)

That's not a Nissan VLSD centre. See attached imaged for Nissan viscous centre. Red arrow points to side gear visible through notch in end of centre case. Green arrow points to 1 of the spider gears visible through hole in case. Yellow arrow points to viscous unit hiding right in middle of diff centre.

post-66906-0-61288000-1313823311_thumb.jpg

Edited by GTSBoy
GTSBoy Grand Master

GTSBoy

Posted
Posted

Don't despair. Looking at your attached image it's a little hard to see and be sure. Look at this pic of a Cusco 2 way. http://j-trade.cranky.jp/IMG_P6287.JPG . You can clearly see the two ramps on each side of that central spindle. This one is perhaps harder to see, but you can see that the casing is different (with a hole in it more like yours). http://t1.gstatic.com/images?q=tbn:ANd9GcQVRWL705gCzkuwyZJ5j3R29ase1wHOYGbRm_xq3JUwfqRf9zJGsw

See if you can move your diff centre around a bit to see your ramps more clearly.

Also, have a look at this thread http://www.skylinesaustralia.com/forums/topic/170563-gtr-skyline-differential-types-helical-mechanical-viscous-etc/ and see what other images of LSDs you can google up to see if you can recognise the maker of your diff. As I said, I'm no expert, so I don't recognise it.

cheers

Beer Baron Grand Master

Beer Baron

Posted
Posted

I think it might be a stock GTR diff (which are 2 way). the diff ratio on it is 4.111:1, get some better pics. it's impossible to tell what it is as we can only see part of the ramps.

Beer Baron Grand Master

Beer Baron

Posted
Posted

yeah, ok that casing is completely different. definitely aftermarket of some kind then. jsut look at pics of casings till you find one with those little bands on it. that should at least identify the brand, then you just need to get a good look at the traction ramps to find out of it's 1 way/1.5way/2way etc.

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