warranty
 

My 98 mustang is still under warranty. If I replace my 2.73 rearend with a 3.45 rearend from ford and have ford to the install, does it void my warranty?

Easiest way to find out is to ask the dealership. Go to their Service Dept. Someone will know. My guess is, yes, it probably will. You never know...

Go to a dealer and ask. If they say that it would be ok, be warned that what they say isn't always what Ford will say. Best bet is to get it directly from the service manager "in writing" this will cover you in most cases. The manufactures can always say that any modification to the vehicle will void a particular part or the entire vehicle. I had one try and tell me that the CARB certified MSD-6 ignition unit I installed voided the power train warrenty.