Hi, Can anyone give me info on rebuilding a N/A diff (are there kits available ) or what services are available in western australia so it can be sent away etc............ thanks
Cheaper to look at replacing it with a 2nd hand unit. The job of replacing the diff itself is not too difficult. Unless you want to upgrade to a 1.5way lsd or so, in that case i would budget about $1500.
you can pick up 1.5 ways or 2 ways off ebay second hand for the $500 mark, as the R200 diff, which the Na uses, is the same as most skylines aswell. whats your problem though, how come it needs a rebuild?
it's got some bearing noise and doesn't lock up as hard as it should. Whitenight should be able to explain better as it's his old diff. It's a spare to be rebuilt so spota's car doesn't have any down time, and by getting it rebuilt there isn't the risk of a second hand diff flogging out in a couple of months So does anyone have any experience with rebuilding the stock diff?
It is quite easy to rebuild the diff, there are no kits available but any good bearing place can get the required bearings, seals and shims. One word of advice for your set up Anton, run it with about half the specified backlash, this will prevent a fair ammount of pinion walk when the 45 torques up.
cheers Eric, but I was just giving more info for those playing at home, Sean has the diff not me stock backlash will be fine for him. For me to adjust the backlash to be tighter for the 45, whats the process? From memory it could be done on the falcon diffs without opening them up by undo'ing the nut behind where the tailshaft bolts up and winding the bolt in? is that right?
No, if you over tighten the pinion nut, you will get more back lash and a wear mark towards the toe of the tooth because the tighter the pinion nut is, the more it crishes the crush washer, hence pulling the pinion forward and away from the crown wheel. The BorgWarner 70 or 78 series as used in most Commodores and Falcons uses a "crush washer" on the pinion shaft instead of a shim like most other diffs. With pinions that use shims like the R200 and 230, over tightening the pinion nut will give to much pinion bearing preload, end up bearing noisy and will wear the pinion bearings very quickly. You need to set the pinion shaft further into the diff by using a thicker shim, then set the carrier/crown wheel towards the pinion gear by using a thicker shim one side and a thinner shim on the crown side of the carrier. You will end up with a wear mark off centre towards the heel of the teeth. Just FYI, the toe is the peak, the heel is the valley or bottom of each tooth. Pinion shims are available in 0.050" and 0.075" from Nissan and alot wider range of sizes from diff rebuilders or bearing supplies. The most common reason for ring and pinion failure in high torque applications is the pinion trying to walk up the crown as the torque is applied, it is this movement that overloads the teeth and breaks them. By stteing it up with less back lash, when the torque is applied, the pinion will continue talk walk up the crown wheel as before, but because you have set it deeper into the heel of the crown wheel, it will go very close to where it should be in its intended application. This is what makes the right Ford 9" so strong, twin rib pumpkin/case with wide pinion support bearings. It is not neseccarliy the size of the crown that gives a 9" its strength. The R230 is very strong, but if you got it out to rebuild it knowing that your application will put more strain on it than what nissan intended with the TT, you may aswell set it up to suit. Also in high power applications I swear by a product called Two2cool, it is an oil additive that will drop the temps signifiacantly. It can be used with alomost any oil whether it be engine, auto, manual, diff, hydraulic or power steer. It is available from most good motorbike shops, I know Yamaha over here stock it. This stuff is pretty close to magic in a bottle.
thankyou, very good info there. The shims your talking about are placed between the pinion shaft and the housing then to set the pinion in deeper to the crownwheel, right? Is it obvious when assembling it how thick a shim you can use?
The shims are between the bearing and the pinion shaft. When you assemble it use feeler guages to set it to where you think it needs to be, then bearing blue the teeth, while holding pressure on the crown rotate the pinion and see where the marks are. Once you start playing around with it, you will get an idea on what to do to move it around.
Instead of setting it to mark the centre of the tooth, set it to mark about 1/3 the way up from the heel.
Hey all, thanks to everyone for the info amazing response as per usual on this section,extremely helpful. Will be a learning experience for me ,looking forward to stripping it down.!! cheers sean
