I just bought an Aluminum driveshaft from Driveshaft shop and install in my car. I tried to look up on how to install the drive shaft but there are no info. Finally did it my self, I love it but i ran into a problem.
There are vibration on 6th gear when accelerate and pulling from engine when foot of the gas, it only happen at 6th gear, same rpm at 5th gear went very smooth.

The thing i replaced was:
- new wheels and tires, balance 4 times
- one year alignment
- transmission mount
- make sure to connect the bolt correctly to the pinion yoke


Does anybody have the same problem?
PS: my car is in the shop for diagnostic.

 

Yes. I had the same problem. I noticed some resonating in the drivetrain in 6th gear specifically with my aluminum drive shaft. For that reason I am going with carbon fiber next time.

Literally all other gears were fine, just 6th caused some womp womp womp womp on the highway if you know what I mean

 

I took my car into a shop where they can diagnose he vibration. Cross my finger it is not transmission, i got a quote for rebuild trans for $1500. There are so many thing went wrong with my car but i have already put in too much effort to give it up.
What is the mileage on your car?

 

I would focus 100% effort on the axles because one of them is probably worn out (problem only exists when you put torque load on the axles) but I asked around and a buddy of mines dad that builds drag cars suggested looking into a propeller shaft dampener, basically it's an inertial dampener that clamps around the propeller shaft but you need to determine which end the vibration is originating at because you want it clamped close to that end. I've never personally seen an issue like this that wasn't due to a mechanical defect but he said in ultra-high speed applications (200+ mph) it's fairly common with lightweight driveshafts like that.

Also, get your tire Road Force Balanced, not just a traditional balancing machine, it still might be a wheel + tire problem but it's probably the axle shafts.

 

I would doubt it’s the transmission - I agree with him ^.

 

I effectively isolated the issue to the prop shaft inadvertently during my last build. This is in my case... But in my mind we both have the same problem since so few people run DSS shafts and nobody but us has a 6th gear specific issue...

For those of you who haven't experienced this, you can literally hear it coming from the prop shaft. You can hear the hollowness of the shaft being projected.

I took my tranny, axles, and differential and put them into a different- higher mileage- car with an oem driveshaft instead of the aluminum one from DSS.

No drive train resonating in 6th now, AND I added aluminum subframe mounts + poly bushings in rear which would make it worse if it were an axle or the tranny itself.

I lived with it since my car was a rattle box anyway. I don't miss it since switching to the oem carbon shaft.

 

Should be able to solve a harmonic vibration issue like that with the shaft dampener. Thats pretty crappy the manufacturer wouldn't take steps to reduce or eliminate the problem though they probably don't spin test their shafts with a load on it.