news to me.. ive fitted at least 20 of them by now "shrugs" are you using the rear section of the 4age pump mated to the new front housing? The front section will fit up to ALL rear sections, the only difference is the front bearing size on the rwd unit is stronger ( and a little longer from memory too ) to cater for the extra weight of the clutch fan.. a fwd front unit will not last long ( trust me ive broken them trying to do it cheaply before ) and they can end up cracking the casings