Mini Spool Diff

[gilly_ECR33]

i was just wondering how hard it would b to take out the mini spool in my 33 and replace it with the standard LSD?

[Krishy]

guessing it would only be a matter of undoing the drive and tail shafts then remove it out of its mounts and swap it over.....please correct me if i am wrong

[Damo_R34]

See below, contains the info you will need to remove and replace

Hey all.I have recently wanted to buy an lsd for my 33 but found the prices a little bit to high.so i pondered and pondered and pondered some more,could i do anything to my stock item to give it better lock.thats when i found out about "diff shimming".

Its a process which puts extra preload on the stock viscious lsd centre,(dependant on how thick it is shimmed),whereby exherting quicker,sharper and more lock than the old worn out stock unit could ever provide.thus giving more torque to both wheels simultainiously.

Step 1:

Jack the rear up nice and high so you have plenty of room to move around.You have to undo the half shafts,tailshaft and diff housing nuts and bolts yet.

Step 2:

Drain the diff oil (make sure you undo the filler plug at the mid way point of the diff).And clean everything up.Ie:The metallic sludge that has formed on the drain plug.Then put it back in place.Tighten it up.You most lilkely wont be un-doing this again.But leave the filler plug loose for the time being.You will use it at the end.

Step 3:

Put the gearbox in neutral and make sure the handbrake is on.Loosen the 4 bolts holding the tailshaft to the diff flange.You can't reach them all.Remove the handbrake and rotate driveshaft to gain access then repeat.(loosen dont remove yet)

Step 4:

Its now time for the half shaft flanges.On either side of the diff there will be a stub with a 5-bolt pattern (gts-t, factory turbo a31/c33) or a 6-bolt pattern (3 lots of 2, regular a31/c33 etc etc).Once again,remove the handbrake and the rotate wheel etc. Some WD-40/CRC/WURTH won't go astray either if this is the first time the diff's ever been disturbed.The reason you do this last and the driveshaft first is that if you unbolted the 2 halfshafts first you couldn't utilise the handbrake to hold the driveshaft still while you undo the bolts.

Step 5:

Now we're ready to remove everything.Before you do this make sure all the nuts & bolts are removed that were loosened off.Lever the driveshaft out of the way with a screwdriver the driveshafts are 5 stud flanges that are just 2 flat faces and are easy to slide out the way.

Remove the hics bolts and lever the hicas out of the way.

Now there are 2 holes & 3 nuts,(the reason there is 3 and not 4 nuts is because one of the nuts holds down an earth strap),remove these first(you may have to lower the diff cradle to gain sufficient access).

Now remove the 4 bolts that hold the swaybar to the floor pan,(this will give you room to manuver the diff out).There are still the 2 bolts at the front of the diff housing by the driveshaft flange,remove these and the diff will fall on the swaybar and sit there.Then it just takes a bit of dicking around to get it out.Utilise a trolley jack to help lower it down easily.

Step 6:

Remove the rear diff cover.

Now,before you do anything else tap the half shafts out of the diff housing.They need a good whack in the right spot(id recomend after every whack or 2 that you turn the half shafts arround to make everything exit evenly).Make sure u mark them left and right.

Now there are 2 bolts either side,undo these and remove the bearing caps (again remember which way around and what side these go on.it is so easy to forget).

You will then see some bearings and spacers and things beside the diff head on either side.Lever the crownwheel & diff centre out with a big bar and make sure u keep all the bearings and shims etc in the correct order and sides.

Step 7:

Now there are 10 large bolts holding the crown wheel on.They are F$$KING tight!!!!! I'd recommend a decent vice and large powerbar or powerbar & 5pound hammer and possibly some WD-40 (dont root the bolt heads) - alternatively a pneumatic gun will work(Dont try to lever off the bearings they arnt in the way.just dont get sand or grit in or on them).

Once the crownwheel's off, you'l see 2 large phillips screws.Remove these and off comes the viscous center.pry these apart with a flathead.

You'll see once u pull it off a washer sitting on a flat surface.That's your original preload shim.

Now if you want to shim up the other side also (i did) you will have to take the spider gears and the smaller centre out of the hat(Housing) and you will find that there is another shim.

Step 8:

Do everything in reverse.

IMPORTANT NOTICE:

Before you screw the diff center back together,after inserting shim and the centre,take the 'longer' of the 2 stub axles and insert it through the center of the diff all the way(in the same side it came out of).This splines the 2 different splined parts of the diff center together so that when you go to insert the diff stubs at the end they'll actually fit (easiest way to explain it).Otherwise you'll be screamin' your head off wondering what you did wrong.

Also when reinserting the lsd and crown wheel back into the housing you can use the caps to push it back into the the housing make sure they are the right way arround.Saves u beating unessisarily on the lsd.

Pour the diff oil in before you put the diff back into the car.

In conclusion:

-Now,ive heard allot of different stories about shims and their results and how long they last.some say that they have added 1 standard 0.8mm shims to the existing shim and it wasnt what they were expecting performance wise.

-others have added 2 extra 0.8mm shims and say that it has lasted them for a long time others not so long but both say that there was a noticeable increase in lock/performance.

-I am the the only person i know of to shim it up to 3.3mm of preload.of course there are crazier.The results were excellent for drifting.both wheels locked consistantly and predictably.I will repost if it ever gives up the ghost.I have never driven or been in a car with either a 1.5way or 2way lsd though i have been passenger in a car with a welded diff.

Side notes:

*There is a little breather plug at the rear top back position of the diff housing dont forget to unplug it before you lower the diff.

*Try to get not dirt,sand,grit etc in the diff or lsd whilst doing this job.keep a cover over things you arnt working with like the diff housing.which now has the cover off etc..

*A bit of WD-40 wont go astray anywhyere it feels to tight to undo

*It is so easy to forget.so mark everthing!

*Clean all your parts before reinstallation.A little smear of clean diff oil wont go astray when putting the lsd centre back together.i also lubed up the shims before i put them back in.The teeth of the half shafts dont need lube.just dont wipe what they have on there off.

Shim Sizes & Prices (@tradeprice):

0.80mm = 3842440f60 price = $10.12

0.85mm = 3842440f62 price = $14.67

0.90mm = 3842440f63 price = $9.97

1.01mm = 3842440f67 price = $9.79

1.05mm = 3842440f68 price = $14.40

1.10mm = 3842440f70 price = $6.37

1.20mm = 3842440f73 price = $6.37

1.30mm = 3842440f76 price = $10.89

1.40mm = 3842440f80 price = $6.37

1.49mm = 3842440f83 price = $6.37

There is nearly allways a wait on these shims so i am told.no-one has them in australia so they have to be ordered from japland.and they have a wait of 1.5-3wks.<<From Nissan Spare Parts.

Attempt this mod at your own risk.I am not a mechanic.this is only a guideline.

[nos man]

so what are you gonna do with the minispool?

Edited October 6, 2010 by nos man

[gilly_ECR33]

got a bloke that wants to swap it for the normal LSD