What is the Mack mDRIVE HD?
Mack offers mDRIVE HD in 12-, 13- and 14-speed configurations. Its manufacturer material describes vocational and off-road applications, with low reduction ratios on relevant versions. The HD label should be accompanied by the exact gear configuration and PTO specification.
What matters in a comparison
A mDRIVE HD proposal should explain the body work, operating weight and manoeuvring requirements. Confirm which low-speed ratios and PTO functions are installed instead of assuming every HD unit has the same package. Ask for the complete application approval and matching operator material. Budget service from the actual duty and records; a vocational feature list is not evidence of guaranteed savings.
Fluids & filters
North American mDRIVE installations covered by Mack’s August 2025 body-builder guidance; confirm the gearbox and cooler configuration.
Reference checked:
Identify the unit first
Use these details to match the manufacturer's application record before choosing a fluid or ordering a filter.
- Full TmD transmission model and serial number
- Direct-drive/overdrive and design generation
- Radiator-mounted versus other oil cooler
- Original filter part number and housing
Fluid specifications
Transmission lubricant
Mack-approved synthetic gearbox oil SAE 75W-80.
Standard mDRIVE configuration identified by brass drain plug; radiator-mounted oil coolers require 75W-80. Confirm the as-built configuration before service.
Source 1 ↗Transmission lubricant
Mack-approved synthetic gearbox oil SAE 75W-90.
HD configuration identified by silver drain plug, excluding radiator-mounted oil coolers. Do not select solely from the mDRIVE HD badge.
Source 1 ↗Filter numbers & cross-references
A catalogue cross-reference links part numbers. It does not confirm that either part fits every version of this model. Match the original part to the unit first, then check the replacement manufacturer's application and any supersession.
Transmission-oil filter element
Cross-reference only: first confirm that OE 20779040 is the correct service filter for this transmission’s model, serial and housing. Baldwin lists this OE number under mDRIVE applications; it does not establish every generation’s fitment.
Application not established by this cross-reference. Confirm this original part number in the manufacturer’s parts catalogue for the exact model and serial number before considering an alternate.
Source 1 ↗Manufacturer catalogue cross-references
- Baldwin PT9417Check catalogue ↗
Mack’s service bulletin calls for a new oil filter when changing mDRIVE transmission oil; drained oil is not reused.
Source 1 ↗Official service and parts reference ↗
What still needs unit-specific confirmation
- The public family page cannot resolve design-level and cooler exceptions. Have Mack confirm the current oil approval and filter supersession against the transmission serial number.
Official service and parts references
Source 1 ↗ Source 2 ↗ Source 3 ↗ Source 4 ↗Follow the current manufacturer's manual for the identified unit. This page does not set a drain interval, fill quantity or repair procedure.
Questions to take to the supplier
- Is this the 12-, 13- or 14-speed version?
- Which PTO functions are configured?
- What vehicle-level application approval accompanies it?
Sources & limits
Manufacturer material supports the identification and overview above. Comparison considerations and supplier questions are Truck University’s original editorial interpretation, prepared with AI assistance. They are not an independent performance test or expert inspection.
Model-family reference only. Availability, specifications and service requirements can differ by year, market and configuration. Verify the actual vehicle or component using its identification and current manufacturer documentation. Do not use this page as a parts-fitment, modification, repair or loading instruction.
Published specifications and examples retain their labelled units; the header preferences apply to calculators.
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