Engineering Differences, Advantages and Failure Modes Transfer cases used in four-wheel-drive and all-wheel-drive vehicles perform the same basic task: distributing torque between the front and rear axles. Internally, however, manufacturers can use very different methods to transmit torque between shafts located on different axes. In a gear-driven transfer case, this is accomplished through a gear train. In a chain-driven transfer case, torque is transmitted through sprockets connected by a high-strength automotive silent chain. Key takeaway. Neither architecture is universally superior. Gear drives provide a highly constrained torque path, but gear geometry — particularly helical gearing — can introduce significant bearing...
Shim Adjustment Before installation, measure dimensions A and B on both the original and replacement flange, then measure the thickness (C) of the original shim. Calculate the required shim thickness using the formula: New shim = (A₁ + C − B₁) − (A₂ − B₂) where A₁ and B₁ are the measurements of the original flange, A₂ and B₂ are the measurements of the replacement flange, and C is the thickness of the original shim. Install the closest matching shim before final assembly. Reference: BMW TIS Repair Instruction 27 10 070.
ATC35L/ATC45L Clutch common issues The ATC35L transfer case clutch, like any mechanical component, can encounter various issues over time. Here are some potential problems that may arise:Wear and Tear: Continuous engagement and disengagement of the clutch can lead to wear of the clutch friction materials. Over time, this wear can result in reduced clutch performance and slippage.Contamination: Contamination with products of wear, dirt, or moisture can adversely affect the clutch's operation. Contaminants can cause increased friction, premature wear of clutch assembly components, and, ultimately, clutch mechanism failure.Incorrect Adjustment: Improper adjustment of the clutch mechanism can lead to issues such as...
ATC35L/ATC45L Main shaft common issues While specific information about the ATC35L/ATC45L main shaft's outer splines might be limited (due to the absence of official detailed technical documentation), issues with outer splines on transmission components are not uncommon in general. Here are some potential problems that could occur with the outer splines:Wear and Stripping: The outer splines can wear down over time due to friction and stress from engagement with other components, such as the rear flange (27107593440 is the most susceptible) or clutch (friction plates). This wear can eventually lead to the splines becoming stripped or rounded, resulting in loss...
Cases when replacing the clutch assembly is required Below are cases in which the entire coupling needs to be replaced. This usually happens as a result of overheating, but it can also be a consequence of poor-quality repairs.Figure 1 shows the separation of the splined part (along the groove of the retaining ring) of the drive gear. Such a breakdown is possible on any transfer case - ATC300/ATC400/ATC500/ATC700.Apart from the case mentioned above, you may prefer to install a new one simply because it consists entirely of new parts assembled and adjusted at the factory.
