JMD

I have a 2001 Mustang V-6 in my shop, with a build date of 9/00.

The car had a replacement transmission (automatic) installed at another shop. Since the install, the car has a BAD vibration, for sure the engine is out of balance BIG TIME.

I came to M/F did a search and found that sometime in mid 2000, Ford switched from external balance to internal balance...

So this made everything make sense, it was easy to assume that the shop used an external balance flywheel on an internal balance engine....

Not so fast.... I start looking at replacement flywheels, lo and behold, there is only one part number covering a plethora of different years on either side of the "2000 change".

Complicated enough right? Not yet apparently... when the shop that changed the transmission "found" the extreme vibration, they swapped in a different 2000 model engine, so now, I don't even know for sure whether the engine is internal or external. I do know that the balancer is for an internal balance engine.

Who can tell me if the internal engines use the same flywheel (flexplate) as the external engines? If it is different why have I only been able to find one listing?

JMD

I have checked parts numbers on 3 "major" parts chain stores and called a local chain, all stores have only one flexplate listed for the 2000 model year, and 2 years on either side of the 200 model year.

How is this? Does the "internal balance" engine, and the "internal balance" engine use the same flexplate?

I have seen lots of posts here covering the balance issue, but I haven't found an answer that might explain this yet.

LilRoush

Look at the crank pulley on the engine (assuming they didn't swap that and mess it up as well). There will possibley be a weighted section visble on the inner edge. I think I have a pic posted here somewhere. Match the flywheel to the correct crank pulley.

I put the wrong fly wheel on one time after swapping one weekend. Vibrated like crazy. Right flywheel and smooth as glass....