Cummins Isx15 Flywheel Housing Torque Specs Jun 2026

Install bolts with light engine oil on threads and under the head. Dry threads produce inaccurate torque readings (up to 30% lower clamp load).

Old gasket material, RTV, or oil on the mating surface causes micro-gaps. Clean both surfaces with a razor scraper and acetone. Then apply a 1mm bead of Loctite 518 (anaerobic flange sealant) around coolant and oil passages only – not around all bolts.

Cast iron housings can handle slightly higher torque, but Cummins standardizes at the same 80 ft-lbs + 90° for consistency. The key difference is that thread locker may not be required on iron-to-iron joints. cummins isx15 flywheel housing torque specs

: Lubricate the threads and underneath the bolt heads with clean 15W-40 engine oil prior to installation for accurate torque readings.

Aluminum housings require precision. The values above are safe for aluminum if bolts are clean and lightly oiled. However, do use the 90° turn on old, reused bolts – they will break. Install bolts with light engine oil on threads

: After torquing the housing, it is highly recommended to check the Total Indicator Runout (TIR) using a dial indicator. For many ISX models, the maximum allowable TIR is 0.13 mm (0.005 in) . If it exceeds this, the housing must be realigned or replaced to prevent premature transmission or seal wear. 4. Related Component Torque Specs

Deviate from these specs, and you risk a leak that requires pulling the transmission – a 10-hour job. Follow them precisely, and your ISX15 will deliver leak-free, reliable service for another million miles. Clean both surfaces with a razor scraper and acetone

In this guide, we will cover the exact torque specifications, bolt sequences, material considerations, and step-by-step best practices for the Cummins ISX15 flywheel housing.

Based on the latest , the flywheel housing uses two distinct bolt types depending on location and engine serial number prefix.

Specifications can change between CPLs (Critical Parts Lists).