Driveshaft - transmission - u-joint angle ?

[GriffX]

I'm looking to minimize the NVH at the Ford 2-piece driveshaft support bearing.

Does someone measured the U-joint angle to the shaft?

I got 2.7 to 2.8 degree, which for me is at the upper limit of 3 degree. The value of a one piece driveshaft is also interesting.
I have a very loud sharp resonance at 65-69 mph.
How can I lower this angle to 1.5 to 2.0 degree? There is an aluminum spacer, but don't know if I can just remove it or must add a thinner one, at least a washer. 0 degree would be ideal for vibrations.

This rubber looks like a circular bump stop, not like all other support bearings from other car brands I have seen so far.

 

[Gladams]

Look into the JXB Performance center bearing support bracket. I have one and I love it. Just my opinion. Thanks.

 

[GriffX]

Look into the JXB Performance center bearing support bracket. I have one and I love it. Just my opinion. Thanks.

That is one option, but, this bracket will also not work if the angle at the transmission is too high, that's why it would be nice if I have some values to compare with. And, the JXB part is 50% of the costs of an 1-piece driveshaft.

 

[Midlife Crises]

While you can add and subtract shims to the center bearing mount you can also use adjustable motor mounts and an adjustable upper control arm on the differential to get any driveline angle you want. Going to a one piece aluminum DS made a noticeable difference in noise on my car. Then I installed a spherical bushing and all the noise came back!

 

[GriffX]

While you can add and subtract shims to the center bearing mount you can also use adjustable motor mounts and an adjustable upper control arm on the differential to get any driveline angle you want.

That's a good point, the motor mounts. The 2nd part of the DS has two CV joints so the angle is not so important.
How to check the motor mounts?
If I could lower the U-joint angle to 1.x degree the vibration will be lower. (the u-joint in the DS at my Mercedes has 0 degree, so the bearing problem can be solved?)

 

[GriffX]

Does anybody of you see some problems to remove the spacer? (I put it right to the bolt now to have the same length screwed in) The distance form the CV joint is approx 2 cm from the tunnel.
The angle changed form 2.8 to 2.3 now.

 

[Kev555]

Is the spacer made of metal Griffx? I know I had my driveshaft off last year but cant remember if these spacers were on it or what they were made of. Might they possibly be nothing more than noise dampeners?

 

[brasil]

..one piece DS. For me the best of all solutions. Until 2005 , all Mustangs had a one piece DS. I had a 68 , 69, 81, 89,90,91,93 94, all with the good old DS. the 90-94 ..all of them were lowered. ( Eibach pro springs ) ZERO issues. My 2010 has a stock suspension.. FR DS.. works great. my 08 was a Bullitt ( perhaps a little lowered from the factory - they say ) also zero issues.

Fideling with the old 2piecer is not worth the time ( my opinion )

 

[GriffX]

Is the spacer made of metal Griffx? I know I had my driveshaft off last year but cant remember if these spacers were on it or what they were made of. Might they possibly be nothing more than noise dampeners?

It is made from aluminium so no dampener. Just removed the driveshaft, the thread insert is a tad higher than the sheet metal, so I need at least a thin washer.
This whole DS is a interesting construction, one U-joint, so no speed compensation, therefore a rubber-bumpstop construction to dampen the vibrations. But, as a good side effect, the support bearing also dampens the force peaks from the gear shift. A one piece DS does not have this and therefore the tires will break lose much easier and probably the JXB option also?

 

[GriffX]

Fideling with the old 2piecer is not worth the time ( my opinion )

But much cheaper

 

[Kev555]

It is made from aluminium so no dampener. Just removed the driveshaft, the thread insert is a tad higher than the sheet metal, so I need at least a thin washer.
This whole DS is a interesting construction, one U-joint, so no speed compensation, therefore a rubber-bumpstop construction to dampen the vibrations. But, as a good side effect, the support bearing also dampens the force peaks from the gear shift. A one piece DS does not have this and therefore the tires will break lose much easier and probably the JXB option also?

Ford put the centre prop in for some reason, possibly for what you described. My driveshaft in quite good shape for 110K but once it kicks the bucket I can either get a single piece or two piece alloy drive shaft made a lot cheaper then the ford performance option at a local rally car driveshaft manufacturer.

 

[GriffX]

My driveshaft in quite good shape for 110K but once it kicks the bucket I can either get a single piece or two piece alloy drive shaft made a lot cheaper then the ford performance option at a local rally car driveshaft manufacturer.

Interesting option. Unfortunately, the main NVH resonance at my DS is right between the 2 main speed limits in Germany 100 and 120 kmh. I hope I can shift it to higher speed with the lower U-joint angle. I will add a shim to the transmission mount cross member also.

 

[Gladams]

My 12, didn’t have the spacers when I put my JXB in.

 

[GriffX]

My 12, didn’t have the spacers when I put my JXB in.

Thanks, now I know that there is no clearance issue.

 

[Kev555]

Interesting option. Unfortunately, the main NVH resonance at my DS is right between the 2 main speed limits in Germany 100 and 120 kmh. I hope I can shift it to higher speed with the lower U-joint angle. I will add a shim to the transmission mount cross member also.

Do you have a standard factory exhaust Griff? i thought there would be more of a resonance of that than your driveshaft? I would always have looked at transmission or rear end as causing resonance rather than the drive shaft. Only thing I experienced that can make a driveshaft hum or have a resonance at particular speeds is a centre prop bearing.

 

[GriffX]

Do you have a standard factory exhaust Griff? i thought there would be more of a resonance of that than your driveshaft? I would always have looked at transmission or rear end as causing resonance rather than the drive shaft. Only thing I experienced that can make a driveshaft hum or have a resonance at particular speeds is a centre prop bearing.

The resonance stays if I press the clutch -> drivetrain. Independent of acceleration/deceleration -> differential unlikely. I hear the noise in the whole car, focus below my seat -> where the support bracket is.
Smoking gun: I already try to modified the rubber at the driveshaft, resulting in a less noticeable sharp resonance, much broader range, from 65 to 85 now. Car is at 90 mph quieter than at 80, that's not good.
So, next approach to lower the U-joint angle (?). Right now at 2.8 degree, the resonance frequency at 65 mph is 103 Hz, that is a drone, with a lower angle the amplitude will get lower. I hop it will get acceptable. Not sure how many shims/washer I can add to the transmission cross member, probably not more than 2 mm, which will not do much.
Stiffer rubber -> broader resonance, lower angle -> less amplitude.

 

[Kev555]

I'm afraid if the bearing is humming all you can do is alter the resonance to different speeds or add grease to it if temporarily but ultimately the driveshaft has to go. If its the rubber mount that's perished-

Maybe something like this might improve the problem? Or at least give you an idea of adding rubber to sound dampen temporarily? Its more designed for a failed rubber more than a failed bearing. Its not cheap either at $299 either and not knowing if it will be a cure.

 

[GriffX]

Maybe something like this might improve the problem? Or at least give you an idea of adding rubber to sound dampen temporarily? Its more designed for a failed rubber more than a failed bearing. Its not cheap either at $299 either and not knowing if it will be a cure.

Yes, the bearing is fine, the rubber is the problem. When I looked at it first, I could push the DS 1/2 inch up with no real resistance. I also noticed that the metal bracket on top is not the same as in your video link. Maybe I have a bad production or revision. Unfortunately, the JXB is 385€ (450$) in Germany, so around halve the price of a full Ford Racing DS.
On the right is my DS and it is clearly different to all others I have seen so far.

 

[Skidmarc]

I'm following this thread with a lot of interest. My new to me 19K mile '14 has the same sharp loud resonance. Mine starts faintly at 65 and between 70 and 80 it's worst then drops to nothing past 80. My car's lowered from stock with Eibach springs. I need to measure pinion angle for myself but am pretty sure it's the driveshaft too. I just replaced both outer axle bearings as the passenger side had some play in it.
I'll pop for the one piece driveshaft from Ford if I knew it would solve the problem. The car's got adjustable upper and panhard, I just don't know if I can get it dialed in on jackstands in my garage.

 

[Kev555]

Yes, the bearing is fine, the rubber is the problem. When I looked at it first, I could push the DS 1/2 inch up with no real resistance. I also noticed that the metal bracket on top is not the same as in your video link. Maybe I have a bad production or revision. Unfortunately, the JXB is 385€ (450$) in Germany, so around halve the price of a full Ford Racing DS.
On the right is my DS and it is clearly different to all others I have seen so far.

View attachment 114681

If that's yours on the right picture it looks to be already modified with a different bracket, possibly a different brand from the one in the YT video I posted or would it be possible the whole driveshaft has been changed? The rubber looks compressed more on yours than the one on the left and you say there's more play in yours? I cant check mine ATM but from memory its the same as the one on the left which I thought was quite soft when I had it off last year . Sorry I also didn't realise Gladams had already recommended the retrofit prop mount I mentioned earlier. My suggestion would be to put a rubber washer between the underside floor and the DS mount to see if the breaks the acoustics travelling. If there's excessive play run a heavy bead of mastic on the bottom bracket giving it a day or so to dry (depending on Temp) and bolt it on again. This should tighten up the play in the rubber. Maybe that might make a difference.