The Case IH STX440QT tractor primary air filter part number is 381423R92. The inner safety filter is 222429A1.
Case IH STX440QT Air Filter Details
Primary air filter part number
381423R92
Inner safety air filter part number
222429A1
Outer air filter part number
Same as primary air filter
Cross-reference part numbers
STX440QT
Air Filter Service Interval Guide
Air Filter Service Interval Guide
Dusty use
100 hrs
Average
500 hrs
Light use
1,000 hrs
These are practical inspection/replacement guide ranges for the large ag tractor category. Dusty work can shorten the interval heavily, so use the restriction indicator and operator manual first.
Case IH STX440QT Extra Air Filter Notes
Engine model
Cummins 14.9L
Engine displacement
14.9 L | 909.3 cu in
Engine horsepower
440 hp | 328.1 kW
Primary filter note
For the Case IH STX440QT, the listed primary air filter part number is 381423R92. Match the number before buying because air cleaner setups can vary by engine, serial range and market.
Outer filter note
The outer air filter for the Case IH STX440QT appears to be the same listed item as the primary filter.
Safety filter note
The listed inner safety air filter is 222429A1. Do not remove the safety element for normal cleaning; replace it if dirty, damaged or oil-soaked.
Fitment note
Check the old filter, air cleaner housing label and parts book before ordering if the tractor has had an engine or intake-housing change.
Power range note
This is a higher-airflow class, so restriction matters fast. If it is working in dust, inspect before the 500-hour planning mark instead of waiting for visible power loss.
Engine airflow note
A similar horsepower rating does not guarantee the same filter if displacement or engine family changes. Use the engine data as a sanity check only.
Cross-reference note
Possible cross-reference numbers found for the Case IH STX440QT: STX440QT. Treat these as secondary checks after the primary filter number.
Service note
Clean loose dust from the air cleaner housing before pulling the filter. Never run the tractor with the filter removed, even for a quick test.
Case IH STX440QT Air Filter FAQs
What should I check before ordering a Case IH STX440QT air filter?
The buying order should be: old filter number first, housing fit second, then cross-reference. Start with 381423R92, but do not ignore the a primary/outer service element plus an inner safety element.
How do I avoid mixing up the Case IH STX440QT air-filter elements?
For normal service, the primary/outer element is the one that does the dirty work. The inner safety element is backup protection, so replace it less often and keep it seated while cleaning the housing.
Can I use aftermarket cross-reference filters on a Case IH STX440QT?
Use the cross-reference to find stock, then check fit like normal. The air cleaner does not care what the seller’s listing title says.
Should I buy separate outer and primary filters for a Case IH STX440QT?
Do not read the primary and outer rows as two separate filters here. They point to the same service element, with the safety element handled separately.
Why does airflow matter on the Case IH STX440QT air filter?
This is a higher-airflow class, so restriction matters fast. If it is working in dust, inspect before the 500-hour planning mark instead of waiting for visible power loss.
Can I ignore letters or suffixes in the Case IH STX440QT filter number?
The primary number looks like a mixed letter-and-number part number. That does not make it automatically correct, but it helps you spot obvious nonsense numbers in search results.
How useful is displacement for a Case IH STX440QT air-filter match?
A similar horsepower rating does not guarantee the same filter if displacement or engine family changes. Use the engine data as a sanity check only.
Official information note
Mistakes do happen. Air filter specs can change by year, engine, serial range, market and air cleaner housing. Check the old filter, operator manual, parts book and official caseih.com website before ordering or installing an air filter.
