Total sales for the quarter were down 11.7% from the prior year, or 9.7% without the currency headwind.
Engine segment sales were down 14%, reflecting a sharp decline in our first-fit businesses.
In our On-Road, sales were down 47% as customer shutdowns were compounded by an already weak truck market in the US and China.
As a reminder, our first-fit On-Road business is only about 5% of total revenue.
In the US, which is the largest portion of our On-Road business, third-party data indicates that our sales fared better than total Class 8 truck production.
Third quarter sales of Off-Road products were down 25%, with more than half the decline coming from Exhaust and Emissions.
As a side note, we continue to work on the transaction related to the sale of our Exhaust and Emissions business to Nelson Global Products.
The total aftermarket decline of 8% was primarily due to a low double-digit decline in sales through the independent channel.
Turning to the Industrial segment, sales were down 6% in third quarter, driven by a 12% decline in Industrial Filtration Solutions or IFS.
Our dust collection business, which makes up 60% of IFS, was hit hard by the pandemic.
Third quarter sales in Gas Turbine Systems or GTS were up 6% driven by strong sales for retrofit projects.
Special Applications' sales were up 5% in the third quarter, driven by strong growth in Disk Drive and Venting Solutions.
Total sales for the month are expected to be down about 24% from last year.
Given that, we feel it's prudent to continue to withhold fiscal '20 and '21 guidance for our key financial metrics.
Despite a sales decline of 12%, our third quarter EBITDA margin was flat with the prior year.
Additionally, our decremental margin was about 19%, which is significantly better than our historic average in the mid to high 20% range.
Third quarter operating margin was 13.4% compared with 14% in the prior year.
These efforts, combined with favorable mix of sales and lower raw material costs, narrowed the third quarter gross margin decrease to 60 basis points.
We had favorability from incentive compensation, which was down nearly $6 million and discretionary expenses were significantly reduced in relation to COVID-19.
At the end of the third quarter, our leverage ratio was 1.0 times net debt to EBITDA, which is where we were at the end of the second quarter and right in line with our long-term target.
Working capital was down from the prior year, driven by reductions to receivables and inventories and our cash conversion in the quarter was 98%.
Out of an abundance of caution, we drew an additional $100 million from our revolving credit facility during third quarter.
Then, later in May, we entered into an additional 364-day credit agreement that gives us access to another $100 million.
Third quarter capex declined by more than 40% and the spend trajectory is consistent with what we communicated previously.
We are committed to the quarterly dividend, which has been paid every year for more than 60 years and increased annually for 24 years in a row.
Our minimum objective in any given year is to offset the dilution related to stock-based compensation, which is about 1% of shares.
We repurchased 1.6% of outstanding shares so far this year.
Donaldson Company turns 105 this year.
This R&D facility is a $15 million investment in building our material science capabilities.

Summary:
As a side note, we continue to work on the transaction related to the sale of our Exhaust and Emissions business to Nelson Global Products.
Total sales for the month are expected to be down about 24% from last year.
Given that, we feel it's prudent to continue to withhold fiscal '20 and '21 guidance for our key financial metrics.
We are committed to the quarterly dividend, which has been paid every year for more than 60 years and increased annually for 24 years in a row.