Infiniti G35 Coupe Quaife ATB LSD and Nismo Diff Cover Installation

October 08, 2009 | DIY Tech | Andrew Wojteczko | Comments (0)

Replacing a rear differential requires a few special tools and some attention to detail but is well within the abilities of a skilled do-it-yourselfer. With the detailed instructions below, we’ve covered the necessary items to watch out for to ensure your install is a success.

Drain differential fluid.
Remove Differential housing from vehicle.
1. Remove rear anti roll bar.
2. Remove wheel speed sensors from differential housing.
3. Match-mark (with a paint pen) propeller shaft to differential and axle shafts to differential.
4. Disconnect propeller shaft and axle shafts (hang/support with wire).
5. Support differential with transmission jack (car on hoist) or floor jack (car on stands).
6. Remove three remaining fasteners (one at rear, two at front). Be sure to note orientation of large washers at forward mounts.
7. Lower differential just enough to access vent line and disconnect it.
8. Remove differential.
Remove rear cover.
Using a dial gauge and magnetic base measure backlash and record this value (spec is 0.0039 to 0.0059”).
Measure torque required to rotate the assembly from the pinion nut. Record this value (spec is 26-33in-lb static, should be around 5 in-lb once rotating).
Label Left/Right stub shafts and remove using slide hammer and flange adapter.
Match-mark bearing caps to ensure they are reassembled in the same orientation/location. We use a center punch and a single dot on the top of the left cap and nearby on the housing, two dots on the top of the right cap and again nearby on the housing.
Remove caps and slide out differential. Using a pry bar in one of the holes in the center of the VLSD should help slide the diff out without binding.
Organize the bearing shells and shims to ensure they are reassembled in the same location.
Measure shim thickness and record the value.
Remove ring gear and clean thread lock from fasteners and gear.
Inspect bearings for any signs of scoring in the shells or blue discoloration that would indicate overheating. If scored or overheated, order replacement bearings. In the diffs we have rebuilt at around 40-60k miles the bearings have all been in excellent condition.
Using a bearing splitter and press, remove bearings from OEM VLSD.
Clean and press bearings onto new differential in the same location as removed.
Install ring gear using Loctite 262 on fasteners. Tighten to 58ft/lbs plus 31 degrees.
Lubricate bearings and shells with a lightweight oil such as ATF.
Install Quaife differential into housing and reinsert shims in their corresponding locations.
Install and torque caps to 69 ft/lbs.

Recheck backlash. If it’s within .0039” to .0059” continue to step 20. If not, follow below.

The total shim thickness must be maintained to keep the same preload on the carrier bearings. If backlash is too low, it will be necessary to shift the differential to the left side of the housing (when looking at the back of the diff) using a thicker right shim and an equally thinner left shim.
With our differential we found the backlash was far too low when reassembled. We measured 0 backlash and the diff was tight and hard to turn. Our shims measured at 2.00mm (right) and 2.55mm (left). We disassembled, flipped the shims from left to right, and then reassembled. Runout was now .010” which was too much. We needed to order shims. See table 1.1 for the available shim thicknesses and part #’s. Shims are approximately $14 each.
We targeted 0.005” of runout and based on some calculations we worked out you can expect an increase of 0.00067” of runout for every 0.05mm increase in shim thickness. Subtracting the starting runout (0 for us) we started with from the target 0.005” leaves 0.005” runout increase required.
Divide 0.005/0.00067 = 7.5
7.5*0.05mm = 0.375mm required increase in shim thickness (use either .35 or .40)
Add the 0.35 to the base right shim of 2.00 to get 2.35mm
Subtract the same 0.35 from the base left shim of 2.55 to get 2.20mm to maintain preload

From the table, it is possible to see what shims are needed to reach our target 0.005” runout. Unfortunately dealers were back ordered on the 2.20mm, 2.35mm shims so we used 2.25mm and 2.30mm and were able to reach 0.004” runout which is in spec (.0039”-.0059”).

Shim Thickness (mm)	Part #	Shim Thickness (mm)	Part #
2.00	38453 N3100	2.35	38453 N3107
2.05	38453 N3101	2.40	38453 N3108
2.10	38453 N3102	2.45	38453 N3109
2.15	38453 N3103	2.50	38453 N3110
2.20	38453 N3104	2.55	38453 N3111
2.25	38453 N3105	2.60	38453 N3112
2.30	38453 N3106	2.65	38453 N3113

You can substitute your starting runout and shim thicknesses into the above equations to determine your necessary shim selection and save money by only having to order the shims you need.

Measure the torque required to rotate the pinion. In our experience as long as the total shim thickness is maintained and runout is correct this will be within spec. If it is out, it’s possible the total shim thickness must be reduced to reduce preload on the carrier bearings. (26-33 in-lb)
Install Nismo rear diff cover using a bead of Ultra Grey silicone sealant or similar. We selected this diff cover because the fins add mass and therefore allow it to absorb and shed more heat.
Install Rear mounting stud and vent tube. You can use a pair of nuts jammed against each other to tighten the stud or the specific stud installation tool seen here. We notched a piece of tube to use as a drift to install the vent tube. They are a tight fit, so be sure to orient it so its direction matches the vent tube on the OEM cover.
The Quaife ATB requires the longer of the two stub shafts to be shortened by 1.7”. The body is hardened but we were able to get a nice clean cut using a horizontal band saw. Be sure to debur any sharp edges before reinstalling.
Clean and lubricate side seals with fresh grease and tap in the stub shafts with a soft faced hammer.
Finally, fill the diff with some high quality gear oil and install on the vehicle using the torque specs found in Figure 1.2. Installation is in the reverse order of removal.

Installing a LSD takes a little time and patience, but with some attention to detail and a few key tools you will be set. Be sure to check out our G35 differential shootout to see the benefits offered by the different types of LSD’s available and which came out on top!