2004's top speed

[joflewbyu2]

any owner's of the 2004 MMs test the top speed ? is it limited like the 03s ? wondering if FMC removed it when they changed over to the stronger 4r75w tranny over the old 4r70w.

[CRUZTAKER]

From what I gathered from Mr. Babcock's Q&A, there was a reason for the limiter, but the MM's (safe) potential is higher.
I assume nothing has changed. It's just a case of call Dennis.

PS:
Why weren't you in Ennis? I had hoped to meet you?

[FordNut]

Steve Babcock said the speed limiter was meant to prevent driveline vibration from the driveshaft. Short version of the story: It may be necessary to change to an aftermarket MMX shaft if you reprogram to remove the limit or if you change to 4.10 gears.

[MapleLeafMerc]

IF one changed to 4.10's, at approx what speed would bad things happen to a stock driveshaft?

[BillyGman]

the 4.10 gears, I didn't notice any vibration at all up to 120MPH and that was the fastest I've ever brought the car up to. However when I changed to 4.56 gears, I was getting a very noticeable driveshaft vibration at 90MPH which caused me to purchase the Dynotech metal martix driveshaft and that did away w/the vibration up to 120MPH which is more than fast enough for me. As far as I'm concerned, you should only be going faster than that if you're on a track, and even 120MPH isn't a speed that I travel at every day. I have noticed that the Dynotech driveshaft does make a whining or singing noise between the speeds of 40-70MPH when I accelerate slightly, but it isn't even noticeable when I accelerate hard. The noise isn't that loud at all though, and it's sure a lot better than the vibration I used to get w/the stock shaft.