Installed Shaftmaster Aluminum Driveshaft, Serious Vibration Problem

[levelbelow2000]

I just installed the Shaftmaster 3.5 aluminum driveshaft in my 2011 5.0. My cars a 6-speed manual car. The install went very easy, everything was good till I drove it. I left my shop and felt a slight vibration, then when I got on the highway, 70-80mph, the vibration is terrible, sounds and feels like when u ride over the rumble strips on the highway. It dont do it when your on the throttle but as soon as u let off the throttle the vibration is there.

So I get off the highway and go back to shop. I put it on a frame machine (flat lift), so the suspension was loaded. I checked to see if it was rubbing on anything and it wasnt. So I thought I might have to index the driveshaft, so I marked it and rotated it on the pinon flange one bolt hole to the left. Then I drove, seemed to get better. I did this 4times till the vibration seemed to go away. But it came back on the ride home.

My car is lowered and I dont have a adjustable upper control arm, so I thought maybe the vibration was because my pinon angle was off. So when I got home I put my stock springs back in it and drove it. Same vibration, I cant get rid of it. I have 2 more holes to rotate it on the pinon flange but if this dont work I dont know what else to try. Any suggestions? Anybody have a similar problem?

 

[stkjock]

Did you check what the pinion angle is before or after the spring swap?

 

[908ssp]

I'll be surprised if you ever get rid of it. That big slip joint in the shaft isn't tight enough to keep the shaft straight. So the shaft moves around on the slip joint throwing it in and out of balance. And the correct angles are simply impossible to achieve with the position of the engine and rear end.

 

[levelbelow2000]

Did you check what the pinion angle is before or after the spring swap?

no i didnt, but I can do it now since the stock springs are back in it. I will check it with the stock springs then I'll check it when I put the BMR springs back in it. But I doubt that is it since it makes the same vibration with the stock springs in it as it does with the lower springs.

I'll be surprised if you ever get rid of it. That big slip joint in the shaft isn't tight enough to keep the shaft straight. So the shaft moves around on the slip joint throwing it in and out of balance. And the correct angles are simply impossible to achieve with the position of the engine and rear end.

That would suck, if I can't get rid of it I will put the stock one back on it. Do alot of people just drive around with a bad vibration?

 

[KJGT]

That would suck, if I can't get rid of it I will put the stock one back on it. Do alot of people just drive around with a bad vibration?

I dunno, I thought the same thing after screwing with different a manufacture one piece (first mod on the car after a CAI). After re-indexing a couple times, making sure all flanges had no runout and getting it rebalanced I gave up.

I put the stock shaft back in after all that, I havent seen many break and i'll live with the extra weight. If the stockers were snapping like toothpicks then I would put up with some vibration..

I'm sure some one piece shaft, ride height, pinon angle and wheel and tire combos are pretty vibration-free but mine isnt one of them.

 

[JimC]

Why not call David at Shaftmasters and see what he suggests? I find that his customer service is great and he will work with you to get it right.

I've never had a problem with the 4" that has been on the car for several years now and over 100,000 miles

 

[Mike@PowerHouse]

The problem is that the "critical speed" of the 3.5in shaft is realitively low. The shaft will basically turn into a jumprope.
The fix is either larger diameter, greater wall thickness or different material. Its a design not install issue.

 

[levelbelow2000]

Why not call David at Shaftmasters and see what he suggests? I find that his customer service is great and he will work with you to get it right.

I've never had a problem with the 4" that has been on the car for several years now and over 100,000 miles

Thats what I plan on doing on monday, I'm going to see what they suggest and see if it dont go away will they return it.

The problem is that the "critical speed" of the 3.5in shaft is realitively low. The shaft will basically turn into a jumprope.
The fix is either larger diameter, greater wall thickness or different material. Its a design not install issue.

thanks for the info, if it dont go away I will see if they will return this one and I will go with a 4in aluminum one or go back to the stock one.

 

[rsb5772]

From what I've read, they are hit and miss, with all brands. I'm going to try my luck at it. My Shaftmaster is supposed to be here on Tuesday.

 

[Rob72]

If you make the centerline of the diff. and trans. parallel that will not minimize the angle of both pinion ends. The only way to do that is to put the diff. pinion on the same plane(-2 deg. for deflection recommended) as the driveshaft. If you don't believe that look at any truck with a suspension lift.

 

[levelbelow2000]

I fooled around with somemore today, cant get rid of the vibration. I put the stock one back on it so I can drive the car. Going to call shaftmasters on Monday and see what they say.

 

[chuck@EvolutionPerformanc]

Sounds like either the shaft wasn't balanced properly, or it may have gotten dropped during shippng.

 

[351inside]

i agree with chuck... must be a balancing issue...

 

[wbt]

The problem is that the "critical speed" of the 3.5in shaft is realitively low. The shaft will basically turn into a jumprope.
The fix is either larger diameter, greater wall thickness or different material. Its a design not install issue.

Not sure I buy this....

I personally feel it has more to do with the slip yoke design vs. a CV joint design.

Pinion angle is the key and may be beneficial to set it properly for this piece to work as intended.

 

[COYO TT]

I have the same DS and am probably on the same springs as you, Steeda sports and do not have this issue with stock uca. I do have a slight banging on ocassion when going over uneven bumps that I have yet to figure out the cause.

 

[Rob72]

Seems like a wider DS would have more vibration than a narrower one.

 

[levelbelow2000]

Called Shaftmasters today, talked to Dave. He was very helpful. He told me to clean the bolt doholes in the pinon flange and re torque everything. So I put the driveshaft back on, did what he said to do, but I still have the vibration. So I called them back and they are going to refund my money.

 

[rsb5772]

Sorry it didn't work out. Are you going to try another brand or stick with the stock shafts?

 

[908ssp]

If you want to try another one. Try the PST they make shaft that is truly one piece no sliding joint to wobble and one end has a constant velocity joint which doesn't have the same alignment issues.

http://www.pstds.com/

http://www.svtperformance.com/forum...t500-pst-carbon-fiber-driveshaft-install.html

 

[BMR Tech]

PST is who we use for our driveshafts. We have used them for the last 7-8 years.

They will take care of you, and you will not be let down with what they offer.

Calvin, I hope you get this resolved.