Driveshaft with 4.10s Question

[halucin8]

Sorry to beat a dead horse, but I have a question about this that I haven't found a clear answer to.

I just got my car back a couple of weeks ago from the Team Collision. I had 4.10s installed while they replaced the entire rear axle. I'm trying to figure out if this new vibration I'm getting is due to the new gears or maybe something isn't quite right with the repairs.

The vibration starts at about 77mph and vibrates for a couple seconds then stops, over and over. I can feel it through the gas pedal and the steering wheel shakes. I've seen where most people say the vibration starts at 120mph or so, but I also saw a post where it started around 70-75mph, hence the confusion.

I can't really take it back to Team Collision because they are in Atlanta and I'm close to Raleigh.

What should I do? Take it to an alignment shop first or go ahead and get a PI driveshaft?

Thanks,
brian

[Krytin]

I don't think the gear change has raised the driveshaft rpm enough to hit a "critcal speed" @ 77mph. The problem w/ stock driveshaft & rear occured @ 120+ mph. Sounds more like a problem w/the installation. Make sure none of your wheel balance weights got knocked off. If the rear axle was replaced due to collision damage - was the driveshaft bent as well? "U" joints can also cause driveline vibs if installed improperly (caps not seated in saddles or loose on one side) or worn.

[DEW34]

Did they change the rear housing cause of crash damage ? if so if it was hit hard enough to bend the rear their is a good posibility that the d/shaft was damaged even if it just knocked a balance weight off of it. it has to be perfectly straight as long as it is .
mike

[Murader03]

What ^^^^^THEY^^^^said. That being said, I drove mine for almost 6 months with the 4.10's prior to replacing the driveshaft with one from Dennis. I never noticed any vibration what so ever and I ran above the posted speed limit on limited access highways back and forth to work daily. There were a vew times I was over the century mark as the highway was deserted at that time of night. I only changed the driveshaft for my own piece of mind, not due to any vibration issues.....

[halucin8]

Dew34, here's a picture of the damage. I will call Team Collision Monday and ask about the driveshaft.

http://www.mercurygallery.net/mmnet/data/2/1588WreckedMM7.jpg

[TripleTransAm]

Dew34, here's a picture of the damage. I will call Team Collision Monday and ask about the driveshaft.

http://www.mercurygallery.net/mmnet/data/2/1588WreckedMM7.jpg


Halicun8, I could be wrong but that photo seems to indicate you have a hint of a rear alignment problem...

:lol:

ahem... okay, seriously, an alignment problem doesn't usually (doesn't ever?) result in a vibration problem (someone correct me if I'm wrong). What you need to do is find out what was reused from before the collision... it could even be a matter of improper torquing of some part during reassembly, whether it was new or old. In fact, I think I recall reading somewhere about the Watts linkage not being retorqueable (don't know why). Mounting points for the rear control arms could have been bent, resulting in an excessive pinion angle. Could be lots of things, but I'd almost recommend setting up a small vacation to drop the car off at the initial repair place to have them go over their work with a fine tooth comb.

[sailsmen]

try putting it in neutral @ speed to see if it is driveline related.

[DEW34]

Halicun wow that was a good hit to tear the rear end up like that.all the replys to you are giving good advice TTa has agood point about what was reuesd and what was replaced , and i think Sails about putting it in netural at speed is a good idea as well . the viberation comes and goes with a certain speed makes me think the drive shaft or maybe even an axle drivers side if it was not replaced has a problem harmonic vibration
just like a fan with a out of balance blade or bent the vibration comes and goes at a cetain speed . you need to give it a good looking at before you drive too much more if it is a drive shaft and its bent it could cause a lott of other problems to the trans tail shaft . oh and make sure if they reused the drivers side wheel rear that its not bent even the smallest of off center bends can cause a vibration
mike

[Krytin]

If they did reuse any wheels I would bet good money wheel weights were thrown off. Make sure the wheels are balanced - the vibration you describe is clasic wheel balance symptom! Increased pinon angle/housing misalignment will vibrate as well and it will vibrate in or out of gear.

[CRUZTAKER]

I would also suggest what sailman said.

But judging from the former damage, you still have issues.

As far the 4:10's are concerned, and I say this about a normal MM that has not had ANY rear end damage, virgin, and a correctly installed gear set. You should not experience any driveshaft issues at normal sppeds. I had mine over 120 many times before I did a driveshaft upgrade with out any vibrations.

I only swapped the drive shaft for piece of mind, and in my case, the awesome price for the now discontinued Metal Matrix Comp POLICE shaft from Alcoa. My MM will never run 140 mph for more than a 10 second blast, and I never run better than 105 at the track. This is appropriate for my application.

I do not solicit this mod in this forum any longer. The majority of the folks here believe that the MMC shaft from Dynotech that costs nearly 200% more is the only way to go.

[Zack]

Halicun8, Mounting points for the rear control arms could have been bent, resulting in an excessive pinion angle.

Should I make new control arms to fix this problem? :rasta:

[halucin8]

Well, after driving to Orlando and back this past week I've also noticed that the front tires are starting to cup. So maybe it's an alignment problem.

Also, my new 4.10s are whining pretty bad during deceleration. Is that something that will go away or were they improperly installed?

[Murader03]

Well, after driving to Orlando and back this past week I've also noticed that the front tires are starting to cup. So maybe it's an alignment problem.

Also, my new 4.10s are whining pretty bad during deceleration. Is that something that will go away or were they improperly installed?


If they're whining that badly, I would strongly look at the install. Nothing like a good Mustang shp to have this kinda work done. Might not be sapced correctly...did they put in friction modifier?