Possibly another solution for driveline decel noise

[turbowop]

Must have a solid axle swap under his gvr4. Sick new mod for wheelin'. /ubbthreads/images/graemlins/hsdunno.gif

 

[Brianawd]

Quote:
Must have a solid axle swap under his gvr4. Sick new mod for wheelin




Ford 8.8 /ubbthreads/images/graemlins/hsugh.gif

 

[evo8ya]

Ok. Since I raised my car back up to not quiet stock height. The decel noise popped up when I never had it before. (stock suspension or evo suspension) I changed the angle of the driveshaft and it went away, so yes lowering or raising your car does abosolutly has an effect on driveshaft angle. Please explain, if you think it doesn't /ubbthreads/images/graemlins/rofl.gif And just for the record... I'm rockin a dana 44 /ubbthreads/images/graemlins/wink.gif

 

[turbowop]

Moving the ride height of the car only changes the angle of the axles, since all the drivetrain moves up and down with the body of the car. The driveshaft doesn't move.

You're smoking crack if you think it does. /ubbthreads/images/graemlins/rofl.gif

 

[4thStroke]

evo8ya, it had to have been coincidence. Mark is right, there is no way to change the drive shaft angle by lifting/lowering the car. Think about where the drive train components are located/mounted and it will make sense.

 

Raising or lowereing your car does NOT affect the angle of the driveshaft. All of your drivetrain is connected to the frame/unibody of the vehicle. So are all of your suspension components. The top of your shock connects to the shock tower (frame of vehicle) and the bottom of the shock connects to the control arm (which attatches to the subframe which is attatched to the frame). You are just changing the resting angle of the control arms (i am obviously using the front suspension as the example). The ball joints on the control arms will be at a lesser distance to the top of the shock tower(again..which is part of the frame/unibody)than with the taller stock spring. Therefor bringing the hubs closer to the shock tower. Now the vehicles frame will sit lower to the ground and your wheel well gap will be lessened. Lowering the vehicle Will however change the suspension angle since the control arm now rests at a different angle causing negative camber of the hub/wheel/tire. This will create abnormal tire wear unless you compensate for the changed angle by adding a camber kit. Get it? Got it? Goooooooooood /ubbthreads/images/graemlins/grin.gif

-Jason
DSMless ATM
used to have 2 1G's....YEARS ago!

 

[4thStroke]

Looks like we might be due for a Brianawdlite as well.

 

The driveline is used to placing tq on the parts from the engine-back, not the other way around. Excessive diff backlash and/or worn bearings in the xfer case may cause decel noises when coasting in gear. This is due to the loading of the parts from the wheels-forward, or reverse of what's normal under accel. Technically why this occurs is beyond me, but it's fairly typical in many rwd/awd platforms from what I gather. Google WRX decel noise as well.

FWIW my car did this since 90,000km and finally subsided somewhat when I replaced the rear diff for an LSD unit. Must have less backlash.

 

[prove_it]

Here's my question going back to the orginal posts, I checked my driveshaft and got all angles within 1 degree of each. I was wondering if there needs to be consideration for angle changes when accelerating hard. I wonder this because doesn't the transfer case "dip" when the engine twists under load? I have poly mounts, but I know it still rocks a bit and was wondering if this would change the angles under load.

 

[belize1334]

I'm trying to align my driveshaft and from the readings I get at the t-case yoke it seems like my engine is pitched backward in the bay. Could somebody with an angle finder measure the angle of their valve cover, say flush with the lettering, relative to ground? Or perhaps relative to some simple chassis angle like motor mount ears, or a specific location on the hood, or something like that...

 

[marvinmadman]

Motor mount 0°
Valve cover 1.25° forward

 

[SouthCaliVR4]

just to put it out there. I had bad driveshaft decell vibration & some noise. When I dropped my driveshaft I found all my u-joints had some amount of binding. this was causing the d/s to flop on decell. was not noticeable under acceleration or steady cruise but decell lit it off. I replaced all the u-joints, carrier bearings & serviced the lobro joint. Last had a friend re-balance the whole shebang. vibrations gone, noise barely there & I blame what remained on the urethane carrier bushings I installed.

In other words if you are chasing any d/s noises or vibrations drop the whole thing out & work each joint in all directions, any binding at all, rebuild the d/s. I understand this is a big ticket @ around five hundred in parts & balance but well worth it to avoid hours of wasted time chasing down problems that don't exist.

 

[belize1334]

Hm. Something fishy here. I get 0* for driver's side motor mount (on the flat chassis section) and 2.5* forward lean on the valve cover (upper lettering) and 3* rear lean at the t-case u-joint.

 

[marvinmadman]

I measured the mount across the "ears"

 

[belize1334]

I have replaced all my u-joints and carrier bearings. The Lobro is original.

 

[marvinmadman]

I took another measurement for you. Placed a straight edge from under the wiper cowl gasket across the valve cover to the radiator support. I butted it against the inside of the cam gear cover. Then measured down to the valve cover bolts and got 2" for the back and 1-7/8" front.

 

[CutlassJim]

When I purchased 1788 it had a nasty driveline noise/vibration if you let it engine brake in gear. Previous owner had replaced everything trying to figure it out. I finally got around to pulling the engine and noticed the splines on the clutch disc were VERY worn and had caused similar wear on the input shaft of the transmission. I replaced the input shaft and disc and the noise disappeared.

Not sure if it pertains to your situation but I figured it's good info for possible driveline noise.

 

[belize1334]

I'll have to check that measurement against mine when I get home. Transmission and clutch are both new within the last two years.

 

[ade]

lowering and raising changes the balance of a car. i have to agree on it affecting the drive shaft, increasing or decreasing the noises the joints make.