[Fulltiming]

Steerable tags: #671, a 2004 was first, second was #681, 3rd was 685, 4th was #697, then all after 697 had the steerable tag axle. Remember that 2004 Newells were likely built in 2003 and may have been using engines built still earlier. Newell used Detroit Series 60 engines primarily until around #723 and 724 (2005's) which had C-13's in them. #726 and 726 (also 2005's) had the C-15. I understand that 744 had an ACERT engine. The last several 2005's all had Caterpillar engines (#752 was the last 2005) although there were a few 2006's with the Detroit Series 60. #1229, a 2008 was the 1st Newell requiring ULSD, although the 2nd Newell requiring ULSD was 1251. Pre-DEF Newells extended into 2011. Interim Tier 4 regulations applied to engines in the 175-750 bhp range beginning with ENGINES built in 2011, and final Tier 4 regulations applying to engines in that power range beginning with ENGINES built in 2014.

Hope this helps.