There have been at least 3 metal bands under name Bulldozer:
1) Italian Speed/Thrash/Black Metal band formed in 1980 and split-up 1992.
2) Finnish Traditional Heavy Metal band formed in 1996 and split-up around 2002.
3) Croatian Heavy Metal band formed in 2001.
And a mythical French punk band in the late 70s.

Italian Bulldozer:
Bulldozer was frequently referred to as Italy's answer to Venom, and on the strength of their debut album, 1985's Day Of Wrath (produced by Algy Ward of Tank), it's easy why this was the case. Alberto Contini's bass and vocals both strongly resembled his Venom counterpart Cronos, and the band's messy Satanic pre-thrash metal was indeed quite similar to Venom's first couple of albums. They survived for a few more years and released three more albums that no doubt diverged from the Venom sound (they are not reviewed here), but for right or wrong, they never really managed to escape the Venom clone tag and never got above cult status.

Finnish Bulldozer:
Was project of guitarist Kim Högberg (who later sung in Helion), bassist Ville Lehtinen and singer Jarkko Ahola (ex-Dreamtale, Teräsbetoni). They had numerous drummers around, for example
Heikki Malmberg, who was also their last, as the band disbanded after he left to Diablo. They released 2 demos, "Bulldozer" and "Love/Hate". Their website (in Finnish) containing free samples: http://www.jahola.com/bulldozer.com/.

French Bulldozer:
2 albums "J’suis punk" 1978 and "Des gamelles et des bidons" 1979, with members from Martin Circus