Allison AT542

Allisonman could you help me please!!!!!

I have a vehicle with a Detroit Diesel and an Allison AT542. The trans totally locked up at 48,000 miles. Could I have got a bad one? I can get an AT545 alot cheaper than a AT542. I thought the only difference was the pan. Will the AT545 be a direct bolt up replacement or will I run into shifting and mounting problems?
Allison AT542

According to our local Allison dealer you are correct. '542 has the short pan. That is what they told me when I inquired about my trans. Cost for a Allison rebuilt unit was ~$1095/exchange. With many on the shelf.