Allison Transmission Inc. reported earnings of nearly $413 million in the second quarter after losing $17.2 million in the same period a year ago.

Indiana Business Journal reported that despite the healthy profit, the Indianapolis-based manufacturer cut its full-year sales-growth forecast to a range of 1% to 3% compared to a prior estimate of 5% to 7%.

Allison, a supplier of motorhome transmissions to the RV industry, said quarterly profit was boosted significantly by a one-time $350 million income tax benefit. On a per-share basis, earnings were $2.28 compared to a loss of 9 cents in last year’s second period.

Quarterly revenue rose 1%, to $559 million.

Allison’s performance was boosted by a 43% sales increase in parts for overseas off-highway vehicles and a 16% rise in military sales. Revenue fell almost equally in North America markets.

The earnings report was Allison’s second since its initial public offering, which raised $600 million earlier this year.

The company reported a $58 million profit on $602 million in the first quarter.

Allison said its new full-year sales forecast reflects “a cautious approach given heightened market uncertainty.”