Fees and Charges
Diff Lab provides very competitive pricing on assembly. Often the cost of assembling a differential plus freight to and from Diff Lab in Brisbane is equal to the cost to build a differential locally. As it usually won't cost you any more, there is no reason why you can't have the very best differential assembly for your BMW.
Regarding quotes:
Diff Lab does not disassemble differentials and provide free quotes on repairs. Due to a heavy workload Diff Lab can provide a rebuild of the differential only. Diff Lab can only work on differentials as a paid job, and never to quote on repairs. A complete rebuild is the only service available for a damaged or noisy differential. Partial rebuilds, and quotes on repairs are not available. The owner of the differential understands that if a differential is sent to Diff Lab, a fully repaired/wrecked/good differential will be provided in return and priced accordingly as per the customer's requirements. The customer has access to all of Diff Lab's pricing online, and work will proceed. Customers who are receiving a full rebuild are aware of this before sending in the differential. All items in need of remedy are remedied to the highest standard. Work will not be performed any other way. Customers should not send in a differential if they do not want it repaired. Customers seeking to send in a diff and receive a quote only, should go elsewhere. Diff Lab will quote on a complete job only, and will almost always provide this quote before the differential is sent in. Generally there are no surprises and the amount charged is the same as the quoted price. If there is a major discrepancy between the quoted price and the estimated final cost (>25%), the customer will be notified.
Regarding exchange differentials:
Diff Lab performs all work on the original differential, or on exchange. Exchange differentials are provided at Diff Lab's discretion. If the original differential cannot be repaired, an exchange differential may be supplied. The broken differential is not returned to the customer. There will never be a scenario whereby a customer orders differential repairs, and receives two differentials back. The customer will receive an exchange or repaired differential only, and not the broken differential, or the remnants of a broken differential. The customer is aware of this before sending a differential to Diff Lab, and has no rights to receive two differentials back when they supplied only one. If a used differential is supplied, the broken differential is not returned to the customer. This is common practice and should not come as a surprise. Do not send in a differential if you expect to receive two in return.
Fees for labour are as follows:
Standard Differential Assembly - $379
Differential Assembly where customer supplies 25%-100% of parts - $529
Differential Assembly where a person has already tried their best, but has fallen hard on their buttocks instead - At least $379 (Diff Lab will contact you if major problems are found)
Ball Bearing Differential Assembly - $429
LSD Installation only (LSD purchased from Diff Lab) - $199
LSD Installation only (LSD not purchased from Diff Lab) - $399
Differential Ring and Pinion Lapping - $190
Rust Removal Bath - $149 (not guaranteed to remove 100% of rust. Takes 24 hours.)
Differential Oil Drain and Disposal - $69
Differential Cleaning - $149
Differential Cleaning of a disgusting mess of filth and horror - At least $149 (Diff Lab cannot guarantee a perfect clean of case exterior)
Differential Disassembly and Disposal - $39
Re-Stocking Fee - 15% of item's listed value
Differentials which are dirty, oily or greasy will attract a cleaning fee. Differentials which are not drained will attract an oil disposal fee. Differentials which are too rusty to work on require a 24 hour rust removal bath and will attract a fee. If you require the removal of a ring and pinion from a differential this will attract a small disassembly fee. The disassembly fee includes disposal of the case and other items which are unused. Items which are special-ordered at your request and are no longer wanted will attract a 15% re-stocking fee.
Diff Lab offers free packaging for freight, with no handling charges. Differentials are plastic wrapped, bubbled wrapped, with protective foam added on the cooling fins, all free of charge. Diff Lab can organise courier pickups of differentials at no extra charge on top of the freight cost.
Assembly Time
Custom differentials which require CNC machine work take longer than standard differential builds which don't require CNC machine work. These are 135i Manual, 235i Manual, 335i Manual and 435i Manual. Any other differentials with welded crown gears also have longer lead times. Often these are available on exchange for immediate change-over. If they aren't, they are processed in batches and may take 3-4 weeks before the batch is complete. Diff Lab generally keeps the 188L and 215K sized differentials fitted with Helical LSDs in stock for immediate exchange. You will be informed up-front if there is no exchange diff available. Once work has begun on your differential, there is no way to re-assemble the unit after the ring gear has been cut off the carrier. Work must proceed with the LSD fitment in order to make the differential functional again. There is no financial compensation available if you decide that you cannot wait for the CNC work to be completed, and your differential is finished.
Noisy Differentials
Diff Lab's focus is the assembly of racing differentials with custom and aftermarket limited slip units. Diff Lab can repair blown and noisy differentials also, but there is risk carried by the customer in doing so. 168/188/L/LW differentials fitted to 1-series, 2-series and 3-series BMWs may suffer from premature bearing failure, ring and pinion failure, and spider gear failure. Diff Lab can replace the bearings in these units with new OEM parts. The differential may fail again. If the ring and pinion is badly worn, the metal contamination may spoil the new bearings. This is not a manufacturing defect in the bearings. Diff Lab takes no responsibility if the differential suffers bearing failure again. The customer has been warned up-front of the issue, and accepts responsibility for the differential. 188L/LW differentials suffer from premature ball bearing failure, and excessive ring and pinion wear, though not as frequently as the 168L/LW units. It is possible to strengthen only the carrier bearings in these 188LW units with upgraded taper bearings. The problematic pinion ball bearings remain and these are not covered by any kind of warranty if the heavily worn ring and pinion is contaminating the oil. The customer is warned up-front about differentials fitted with ball bearings.
The way to know whether or not a differential has accepted a rebuild (and gear lapping) is to drive the vehicle. It is not possible to test the ring and pinion to determine whether it is going to contaminate the oil again. If a differential has had gear lapping, and becomes noisy again, it may have to be considered not repairable. Diff Lab can offer another rebuild, but it is rarely advised.
At Diff Lab there is no provision for working on vehicles. For diagnosis of noisy differentials it is best to attend one of Diff Lab's partner workshops. Diff Lab accepts responsibility for diagnosis only when performed by a partner workshop.