Synthetic Transmision Fuid?

[srh]

I'm about to purchase a 2005 Essex 4502 pending PDI. I was told by the owner that it has synthetic transmission fluid, good for half a million miles. Any opinions or thoughts?
Thanks,

[Steve Ownby]

He is misinformed. Here is an Allison publication with a lot of info. If the Essex has a Cummins ISM the transmission will be the Allison 4000. One of the two filters should have been changed at 5,000 miles. In about '07 Allison improved their filter and eliminated this 5,000 mile change. This coach should have had the two filters changed every 36 months. The fluid should be changed every 48 months or be sampled and tested.

http://www.allisontransmission.com/s...t=SA5429EN.pdf

If this has not been done, it should be a condition of the purchase.