Kaaz LSD Installation - July 8, 2008

I decided to get a 2-way LSD from Kaaz since it seemed to be a quality item that is very popular among drifters and relatively affordable. I researched a few other options before making my decision. The ATS/Carbonetic differential seems like it's a more durable LSD, but it is a lot more expensive than the Kaaz unit. I didn't think the extra durability would be necessary for a car with stock power. The Tomei unit was priced about the same as the Kaaz, but I read that Kaaz actually manufactures the Tomei LSDs and that the only advantage of a Tomei is that it tends to be quieter. Since noise isn't an issue, I went with the Kaaz LSD.

I purchased the 2-way LSD as opposed to the 1.5-way because it was less expensive and should provide better stability at corner entry. The purpose of a 1.5-way LSD is to keep the differential from locking aggressively when the driver gets off the gas and is decelerating. This helps the car turn in at corner entry. On the other hand, a 2-way LSD locks equally aggressively on acceleration and deceleration, which can make the car understeer on corner entry. However, for a car that naturally tends to oversteer on high-speed corner entries like my car, a 2-way LSD should, in theory, stabilize the car on corner entry. If the LSD does lead to understeer, I should be able to change the handling of the car with sway bar and shock adjustments.

The Kaaz LSD came with all of the parts for installation including new bearings, axle seals, gasket, and a bottle of gear oil. I purchased three additional bottles of gear oil since Kaaz recommends that it be changed after initial break-in and every 3,000km afterwards. I ordered the LSD last Sunday from 240sxmotoring.com for $795 and the Kaaz Oil for $44.50 per bottle.

Kaaz LSD and gear oil delivered by UPS Kaaz LSD box open
Kaaz LSD box Kaaz LSD contents in box
Everything that came with the Kaaz LSD Kaaz LSD in plastic and box
Extra Kaaz gear oil
  1. I first removed the center section of my exhaust (part that connects the catalytic converter to the muffler) so that it would be easier to remove the differential.
  2. I removed the four bolts that attach the driveshaft to the differential input and lowered the driveshaft.
  3. Then, I removed the six bolts that hold each axle to the differential outputs.
  4. I supported the differential with two stands, one at the back and one at the front of the differential.
  5. Next, I removed the four nuts on the back of the differential and the two bolts on the front holding the differential to the subframe.
  6. I lowered the stands slightly to get the differential into a better position to remove the axles. With the differential slightly lowered, the axles can be wiggled out and the differential removed from the car.
  7. With the differential on a table, I removed the drain plug to get the gear oil out.
  8. Then, I took off the rear cover.
  9. I removed the axle shafts by carefully hitting them outward with a hammer and prying them out. I layed them on the table according to which side each came from.
  10. Next, I removed the bearing caps and rolled the open differential out of the pumpkin. I had to use a pry bar to get it out. I placed the caps and spacers with the axle shafts on the table to remember which side they came from.
  11. I removed the axle shaft seals from the differential case using a flathead screwdriver and hammer and installed the new seals that come with the Kaaz unit. I placed an old seal on top of the new one and hit it with a hammer to get it into place.
  12. I unbolted the ring gear from the open differential and cleaned the Loctite from the threads of the bolts with a steel wire brush on a grinder. I tapped the threads in the ring gear to remove any remaining loctite and blew out the debris with compressed air.
  13. I applied Loctite thread locker to the cleaned bolts and attached the ring gear to the Kaaz LSD.
  14. I couldn't hold the LSD in order to torque the bolt to the required 98-112 ft. lbs. and didn't want to damage it by putting it into a vice. Therefore, I used an impact gun to tighten the bolts as much as possible.
  15. I removed any bits of old gasket from the pumpkin before installing the LSD. The old gear oil and the inside of the pumpkin was pretty clean so I didn't feel the need to do any further cleaning.
  16. I greased the bearings and placed the LSD in the pumpkin leaving out one of the spacers so that it would go in easily. Then, I tapped the remaining spacer into place with a rubber mallet.
  17. I put the caps back on their respective sides and torqued the bolts (65-72 ft. lbs.).
  18. I inserted the axle shafts back into place and tapped them in with a hammer.
  19. Next, I chiselled away all of the old gasket material on the rear cover and cleaned the inside of the cover.
  20. I installed the differential cover back on the pumpkin using the new gasket supplied with the LSD.
  21. I filled the differential with a full bottle of Kaaz gear oil.
  22. Finally, I re-installed the differential back into the car.

On 240sxmotoring.com, it says that a bottle of Kaaz gear oil is good for one fill of the differential. After installing the differential back into the car, I removed the fill plug to check the fluid level. There was a lot more fluid than is recommended in the FSM. According to the FSM, the fluid level should be just up to the bottom of the fill plug (just barely pouring out when the fill plug is open). I drained a bit of the fluid so that the fill level would meet factory specifications.

I didn't have a chance to break in the LSD today, so I will be doing that tomorrow. I didn't find it in the instruction manual, but a write-up I read online of a Tomei LSD installation said that the car should not be driven faster than 40mph for 60 miles after installation. I'm not sure why this is necessary, but I did keep the speed below 40 when driving home just in case.

Some LSD installation guides say to apply gear marker on the ring gear and turn it to see if the pinion gear is contacting the center of the ring gear. If not, the LSD needs to be shimmed so that the gears make proper contact. Since I didn't have any gear marker and didn't see this step in the instruction manual, I assumed that the LSD would be constructed to make proper contact between pinion and ring gear with the OEM spacers installed. Also, I read that if the gears are not making contact properly, the LSD will make a noticeable whining sound. The LSD was very quiet driving home so I assume that everything is fine.

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