PHOENIX (AP) _ Motor Coach Industries Inc. and Mexico's Consorcio G Grupo Dina said Wednesday that their once-troubled merger agreement has been amended and approved by both boards of directors.

The stock-swap deal - in which bus and truck maker Grupo Dina will acquire rival Motor Coach, formerly a unit of Dial Corp. - is currently worth $337 million.

But the value could change depending on Grupo Dina's stock price, said Motor Coach executive vice president Craig R. Lentzsch. The companies last month said the merger might be called off because the value of the Mexican company's shares had fallen below the agreed upon range.

The companies have negotiated a new exchange ratio involving Motor Coach's 20.2 million shares, Lentzsch said.

Grupo Dina now will aquire 51 percent of Motor Coach's stock by trading 1.236 Dina American depository receipts for each Motor Coach share; it will offer $16.72 per share in debt securities for the remaining 49 percent.

Motor Coach shareholders will be allowed to chose between ADRs, which represent stock in a foreign firm that is sold on a U.S. stock market, or debt securities.

The original agreement called for Grupo Dina to issue $16.72 in stock for every Motor Coach share. However, Dina's stock price fell below the $20 to $30 per share range discussed.

Motor Coach builds buses in the United States and Canada. Dina makes trucks, tractor-trailers and buses.