RickB, Thanks for your reply The battery tray at the firewall/fuel tank end narrows down. The tray "steps" down. Bought this tractor used about 3 years ago. It does not have the cold start feature that my 4400s have even though it was purchased new by a local municipality. (Guess they kept it in a heated building.) Yes, my two 4400s take the 4DLT. Perhaps the tray has been changed. The hold down does not appear to be original either as someone added a crosspiece to narrow it. I shall try measuring my 4DLTs against the tray in the 3400. Than ks again