2004 Pontiac Bonneville swapping transmissions

2004 PONTIAC BONNEVILLE
140,000 MILES • 3.8L • V6 • FWD • AUTOMATIC
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NOTAPROMIKE2
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I want to swap transmissions from a parts vehicle to my 2004 Bonneville.. My 04 has a slightly different gear ratio (FQ3, 2.86). The tranny I am about to install is the F83 with a 3.05 gear ratio. They both have codes MN3 and L36. Will this cause any problems? The parts man at a dealership thought it may mess up the computer and encouraged me to get the exact match. Is this necessary? Will it fit and work properly if I make this swap? Thanks. Notapromike
May 20, 2014 at 7:43 AM
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WRENCHTECH
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Yes, it will mess things up somewhat. Speedometer will be wrong. Fuel mileage will suffer. Trans may not shift at the right time. The computer was programmed to a different ratio so the computer is going to have specific responses at specific RPMs and that is going to be all changed.
May 20, 2014 at 8:49 AM