I put 3.73's in my 5.0's, & I had to go to the aluminum FMS driveshaft in both cars afterwards to get rid of driveline vibrations that I felt with the shorter gears. (Couldn't feel them before the swap because the driveline wasn't turning as fast at my normal driving speeds.) Should I budget for the aluminum driveshaft once again when I swap gears in the Cobra? I assume so, but wanted to get some input from guys who have done it already. I'm planning on 4.30's.
I have 4.30s in my 1996 Cobra with a stock driveshaft, but I would recommend an aluminum one. It drives fine up until around 100mph then it vibrates like hell. I plan on getting one as soon as I can afford it.
I would suggest getting it while you get the gears, it is only an 180 bucks and can be swapped in the driveway!
I wonder if that is my problem also. I put 410's in the car at the end of the season last year and noticed a bad vibration around 110mph. I was attributing it to bald rear tires (i got some new ones on it now) and hoping this year when i take it out and open it up that the vibration will be gone. How can you be sure it's the driveshaft vibrating? and what drive shaft should i go with?
I'm running 410s with a stock driveshaft and it drives perfectly, even above 100mph. I had read that there would be vibrations so I was considering it, too. The place that did my swap (Xtreme Mustang Performance - Eric Cheney, Owner) said that there is no reason to swap to an aluminum driveshaft other than track racing. They said they've never had a problem with vibrations when swapping gears. My car drives as smooth and quiet as can be (at least as far as the drivetrain goes )
If you get a vibration @ high speed after a gear swap, it's most likely the driveshaft. I've used the Ford Motorsport driveshaft twice now, & will again on the '97 if I need to. I don't have any experience with other aftermarket driveshafts.
I installed the 4.30s in my cobra myself and have no drivetrain vibrations with the stock driveshaft still in there. I would of thrown one in there anyways like I have done to my previous 5.0s but I plan on going to viper six speed which calls for a custom length so I thought of it as a waste right now.
I got 3.73s in my GT and my friend has 4.10s in his 98 cobra and we have both had no vibrations. Even above 100mph.
When i am accelerating ususally at about 110 i get a real bad vibration from my shifter. . .could this be the driveshaft or maybe something else?
Hey mtbiker78...do you have any problems with your Motive gears at all...like any rear end whine? Thanks
Cobravenom....my gears have been great! you can hear a small whine, but that is because of the Tri-Ax. With a stock shifter you probably wouldnt' hear the whine. But NO i don't hear a "rear end" whine with the Motive gears, so far so good! Hopefully soon i'll be able to figure out what the vibration is! it was either my tires or it IS the driveshaft...
Even if you don't *need* the alum shaft, I think it would still make for a nice upgrade if you were planning on doing the gears. Less rotational mass, etc...
mtbiker78...that has been the answer I have been looking for because I just purchased them and I keep on hearing different opinions on them. Thanks again
I have a 98 Cobra with 4.30s. Here are the vibration results before and after the gears: ----------------------- Stock gears/driveshaft: ----------------------- 000 - 150mph = no vibration. --------------------------- 4.30 gears/stock driveshaft: --------------------------- 000 - 100mph = no vibration 100 - 125mph = very bad vibration 125 - 150mph = vibration goes away.
Certainly, but it nearly doubles the parts cost. Throw in a Speed Cal, & a gear swap suddenly gets a good deal more expensive than it first appears. It's more enjoyable to plan on spending $190 for gears than $500...
I would have added one just because of how pretty they are! Sometimes I just lay on my garage floor and look up at it. They are an upgrade on their own, and in theory offer quicker acceleration.
