That's a good question...I'm not sure. From the ads I've seen it has to be at least 50/50. They seem to be more common on later/bigger tractors. Karl In a message dated 3/6/04 6:34:17 PM Eastern Standard Time, leroy_price3 at hotmail.com writes: << Thanks for the info Karl. I'm wondering if there are more 300s/350s with TA then without. LeRoy >>