Before You Start
Due to the extensive list of different final drives
installed in BMW vehicles, particularly across
different countries, there may be instances where a
the LSD gearset offered differs dimensionally with
the gearset installed in the vehicle concerned. It
makes good sense, therefore, to check the gearset
installed in the car at the earliest possible time. In
most cases, it is possible to remove the rear cover
of the final drive to check the critical dimensions
before committing to the conversion.
The critical dimension is the crownwheel to bearing
dimension, marked L4. This can be checked
visually by offering the LSD up to the existing open
differential. If there is doubt about the configuration,
then check the BMW number as below.
BMW Part references, location on differentials
On a BMW "open" differential gearset, the last 7
digits of the part number are located on the rear of
the crownwheel flange. (1 216 158)
On a BMW LSD, the BMW part number is located
on the clutch drum. (1 117 242)
These numbers are the only absolute references that can enable a match to a Quaife ATB LSD. In most
cases these numbers can be observed by removal of the rear cover. In some cases, however, it may be
necessary to remove the entire final drive.
Please also give the following information
Final Drive Casing BMW Number
(Seven digits cast into casing)
Chassis Number
(Last seven characters)
Transmission Type
(Manual/Auto/SMG)
Replacing differential in final drive.
Removing and installing final drive- refer to BMW TIS for the vehicle concerned.
Drain off fluid.
Secure final drive to BMW special tool 33 1 010 (retaining bracket) or similar.
Remove rear casing cover, and press off both drive
flanges with a tyre iron.
Remove output shaft seals and bearing outer race circlips.
Caution! do not mix up bearing races and circlips.
Changing the total thickness of circlips will change the
friction torque value. The friction torque of the pinion
bearings, the backlash and tooth contact pattern will not
have to be adjusted again provided the circlips and
bearing races are reinstalled in their original positions, and
the pinion assembly is not disassembled.
Remove complete differential gear set from casing.
Press off Bearing Inner races. Take care not to bend the
bearing cages. Ensure that the bearing inner races are
retained with the matching outer races. If the vehicle has
covered more than 50,000 miles, they might require
replacement.
Press or tap off crown wheel (cold).
Installation.
Press on bearing inner races to new LSD gearset.
Heat the crownwheel to 100 degrees (immerse in boiled
water), and place it onto the new LSD gearset, taking care
to align the bolt holes. Ensure no water remains in the bolt
holes prior to installing the bolts. (risk of hydraulic locking)
Install the original crownwheel bolts using loctite 270.
Torque specification for bolts is 100Nm +10/ -0, then
torque angle 30' +4/-0.
It may be necessary to reduce the flange diameter of the
crownwheel bolts to 22mm in order to clear the LSD cap
head screws.
Install new LSD gearset assembly, lubricate bearings with gear oil.
Note. In some cases, the complete assembly is too large for the rear aperture of the casing. In this
case, it is necessary to disassemble the LSD gearset, reassembling with the gearset in-situ inside the
casing. See separate instruction below.
Lubricate with gear oil and carefully push in bearing outer races. Do not tap into position. If the bearing
is correctly aligned, it will fall into place. Reinstall circlips in original positions, and install new output
shaft seals.
Crownwheel tangential clearance (drive pinion backlash) should be checked with a dial gauge according
to BMW procedure. It should not be necessary to adjust with shims. BMW tolerance for a new
differential Backlash mm 0.06 to 0.14mm. (0.0024 to 0.0055in.). However, it is possible to run a
differential with backlash of up to 0.20mm, but this will produce driveline shunt (exactly like the BMW MDifferential,
which runs with 0.20mm backlash)
Before installation of the drive flange, place new round wire snap ring in groove of the LSD gearset so
that both ends are recessed in the groove. (supplied) This prevents lateral bending of the ring.
Lubricate the inside diameter with a small amount of anti-seize compound. Lubricate drive flange shaft
with gear oil. Push in drive flange by hand and turn slightly until wire snap ring is heard to engage.
Clean the faces and install rear cover using BMW sealant or gasket as appropriate.
Reinstall differential into car and fill with oil. Use BMW recommended gear oil, but not LSD oil. Do NOT
use additives or any other fluids designed to reduce gear friction.
Test the final drive by running the car gently between full left and right turns to ensure oil is fully
circulated. Drive the car normally for 10 miles before any aggressive use. No further running in is necessary..
Additional Procedure for disassembling the LSD for loading into 188l casing
If it is necessary to disassemble the
differential to install it into the final drive
casing, all thread locking material MUST
be completely cleaned from the bolt holes
and bolt threads. Warranty claims will
be voided in cases where this procedure
has not been carried out.
Remove the allen head cap screws from the
LSD gearset. Clean any excess thread locking
agent from the screws using a die. Take care
not to cut metal from the threads (use die by
hand, not in a die stock)
Tap apart or press the LSD casing apart, being
careful not to allow the scroll gears to drop out.
Clean any excess thread lock from the bolt
holes with a plug tap (M8x1.25)
If you loose the configuration of the centre
shim stack, this pic. Shows how the
arrangement should be.
Load the crownwheel and LSD crownwheel
flange into the final drive casing. It may be
necessary to remove several of the long scroll
gears to allow installation.
Once the crownwheel assembly is in place, the
scroll gears can be replaces, and the outer
casing carefully put back into place. Note the
position of the assembly dowel hole. This is not
a bolt hole and must align up with the dowel
hole in the LSD crownwheel flange correctly.
Reinstall the LSD Allen head cap screws using
Loctite 270, and torque to 37Nm. Ensure the
bolt holes are free from oil or other materials.
Do not over-use Loctite. Failure to ensure the
bolt holes are clear might result in breakage of
the housing due to hydraulic action.