Truck was my old 98 had a 4.6 auto trans 4x4. Did a 5.4 swap awhile back. New flexplate for 8 bolt 5.4. Also new torque converter. Anyways sold it to a friend. He's gone through 3 flexplates. Cracks them somehow... Sometimes they last up to 3 months. Followed motor swap notes to the T. And also chitons for removing and installing motor. All bolts from motor to bell house are tight. No play or anything like that. Motor is strong. Flexplates coming from auto parts store and rock auto. Where do we start...

 

First thing I would suspect is the torque converter second thing would be starter alignment but that should make a noise and I doubt it would crack the flex plate.... I'll go with the torque converter causing the problem.

 

I bet your right. Yesterday the guy who has the truck said it made some popping noises and then he lost forward and reverse gears. Leaking a lot of fluid from the front of the trans. Does not die when put in gear. Hopefully it didn't take the transmission with it.

 

Just few thoughts, not necessarily answers
Is the transmission mount different from the 4.6 to the 5.4...or maybe the cross member that the mount is attached to, is different? Or is the same transmission??

take it that the "new owner" is not having issues after a day at the races?

 

^^This happened a year ago and ever since... nothing going right for him. If it wasn't my girlfriends brother I wouldn't care. Lesson learned- never sell your stuff to people you know, especially family. I'm sure everyone will agree.

The mounts I believe are the same across the board. They are both ford mod motors. I did not change the trans out. It's the same 4r70 that would be behind some 5.4's. I used a torque converter with the appropriate stall, so it was newish. Maybe 20k miles on it.