Driveshaft Angle

[Toplait]

Hi folks, bought a 2011 Mustang GT Sterling Silver Grey in May 2017. It was lowered by the original owner. I also did a few mods. I ended up having to lower the engine down to fit the Boss 302 strut tower brace using the BMR K-Member and lowered motor mounts with some other mods that I did ect... The Motor mounts must of dropped the engine about an inch. Which equals the transmission tail housing going up. By the way very little clearance between the oil pan and the steering rack for those interested. Maybe 4 sheets of paper clearance. I was thinking about grinding down the K-member steering rack mounting locations to get some more clearance but thats another project If I feel like it starts to rub but so far so good. Engine noise and vibration increased.


=============
Rear Suspension
==============

Any way, I was getting some vibration so I went ahead and did the rear suspension, BMR Tubular Lower control arms, BMR relocation bracket, Steeda adjustable rod end upper control arm, Steeda mounting bracket and also changed out the differential control arm bushing for Steeda Spherical Bearing bushing. For those interested and know what I'm talking about "WTF is up the the cast iron weights mounted to the axle tubes lol? Noise reducers??? =Trash Also, you can hear every thing and feel every thing. Just the engine vibration can give most women an orgasm sitting in the passenger seat. I had one freaking out telling me to pull over and stop going down the damn road one time. I was like WTF? You having a heart attack? Exhaust is loud. Pypes Long Tubes, Off road X-pipe, Corsa axle back.

I also have a DSS Aluminum One Piece Drive Shaft.

----------------------------------------------------------------------------------------------

My question is am I measuring the drive-line angle correctly. I have the car on blocks raised up in the air. I have Two Magnetic Angle Gauges. One on the transmission bell-housing which reads 87.5 degrees. The other angle gauge I have stuck to a metal straight edge square and its put behind the pinion flange which reads 89 degrees. I'm subtracting the angle of the transmission bell-housing from the angle of the differential pinion flange which equals -1.5 degrees.

87.5 - 89 = -1.5 degrees

That sound right? The car is not suppose to be a daily driver but ends up being a daily driver. Weird how that happens...

 

[Toplait]

Okay, so the vibrations are still there, they start at 80 mph now instead of 75mph. Better now with an adjustable arm on it. So I'm heading in the right direction. Took it up to excessive speeds and it is a definite pinion angle issue.

Once I'm off work Wednesday ill put it back on blocks. If I have the motivation ill take the driveshaft off and measure it from the trans flange. Should not matter though since the harmonic damper, trans bell-housing, trans-flange should all be same angle.

Seems like the car is sensitive to pinion angle change.

 

[MG0h3]

When you say blocks, you mean the wheels are on blocks as if it were on the ground? I use the flange or something as close to the yoke as possible as long as its flat.

 

[KBBoss302]

OP - this video should help you. I am sure the the vibration is frustrating.

 

[Toplait]

Update:

So yesterday evening I pulled the old Harbor Freight Digital Angle Finder out of the tool box and of course the 2032 batteries are dead.

So while at work I bought some more 2032's and once I got off work I pulled the car into the shop and put the car blocks. When I say this I mean the cars wheel are resting on wooden blocks not elevated by the pinch joints or the frame. This is to elevate the car to be able to get under it and maintain the ride height and angle geometry of the drive-train.

Starting off the angle geometry looked good. Did not change at all it still said 1.5..."Scratch's head and slides back and fourth to the front and the back of the vehicle a few dozen times." I knew something was still wrong with the vibration I was getting even with a CV joint driveshaft from DSS. After hours of crawling around it hit me. /smack

The rear end pinion was out of phase! It was pointed up. So I shortened the upper control arm about an inch to bring the rear differential pinion facing down.

I took a measurement with my digital gauge. One on the front driveshaft U-joint. This is bolted to the transmission flange and does not wobble. I had to put the vehicle in neutral to get it level. This measurement said 2 or 88 depending on the direction the gauge is placed.

I took the 2nd measurement on the flange of the DSS driveshaft CV joint, "it was the best place that worked well with my digital gauge in a confined space." I managed set the Control arm setting to 1 to 1.3 or 89 to 89.3 degrees, depending on other locations of measurement. For example, using a flat edge on the back of the pinion flange to even taking measurements from the bottom of the pinion flange ect...

(So 2-1= 1) or (88-89= -1)

So its kinda late but I think ill finish eating dinner and go for a test drive just to make sure things don't fly apart on me.

Update:


All Fixed by what I can tell... The roaring noise on and off is gone. Even the high pitch pinion whine is gone. Other then that I think i'm gonna leave the pinion angle there for now until I can further test it in a more safer location.

 

[bmilteer94]

Were you able to do any further testing? I recently installed a BMR k member and DSS one piece driveshaft and I have a low frequency vibration in neutral or in gear that starts around 30mph and continues past that. I haven't been able to check my pinion angle lately but before the install it was set to -1 I believe. I only have an analog angle gauge at work and it's hard to get into tight spots. Where do you get those small digital angle gauges from?

 

[Toplait]

Were you able to do any further testing? I recently installed a BMR k member and DSS one piece driveshaft and I have a low frequency vibration in neutral or in gear that starts around 30mph and continues past that. I haven't been able to check my pinion angle lately but before the install it was set to -1 I believe. I only have an analog angle gauge at work and it's hard to get into tight spots. Where do you get those small digital angle gauges from?

https://www.harborfreight.com/digital-angle-gauge-63615.html

Is the easiest digital gauge I found to use...

Rotate the Driveshaft so that that you can place it flat on the bottom part of the front yolk that bolts closest to the transmission.

Then the rear part of the driveshaft on the differential kinda sucks to take measurements from... Have to take multiple readings in different places. I found bottom of the differential closest to the rear pinion seal if that makes since.

Other then that with the DSS driveshaft CV joint it really does not matter much. Just as long as The DSS meets the specifications from DSS. The CV joint kinda takes care of the issue. I forgot the distance its suppose to be like 2.25 inches or something Id have to look.

My DSS driveshaft makes a that slight clicking-clunking noise when you push and pull up and down....Like most people seem to have. Its not much but I bet that might have something to do with high speed vibration.

I think the issue is your tires in my opinion. That's how it was with me... But I still get a noise-vibration around 80mph but the car is freaking loud. Complete exhaust with resonator delete. When I stick in in Neutral it just glides with out issue except for the sound of the 315/35R20 tires in the back.

 

[bmilteer94]

https://www.harborfreight.com/digital-angle-gauge-63615.html

Is the easiest digital gauge I found to use...

Rotate the Driveshaft so that that you can place it flat on the bottom part of the front yolk that bolts closest to the transmission.

Then the rear part of the driveshaft on the differential kinda sucks to take measurements from... Have to take multiple readings in different places. I found bottom of the differential closest to the rear pinion seal if that makes since.

Other then that with the DSS driveshaft CV joint it really does not matter much. Just as long as The DSS meets the specifications from DSS. The CV joint kinda takes care of the issue. I forgot the distance its suppose to be like 2.25 inches or something Id have to look.

My DSS driveshaft makes a that slight clicking-clunking noise when you push and pull up and down....Like most people seem to have. Its not much but I bet that might have something to do with high speed vibration.

I think the issue is your tires in my opinion. That's how it was with me... But I still get a noise-vibration around 80mph but the car is freaking loud. Complete exhaust with resonator delete. When I stick in in Neutral it just glides with out issue except for the sound of the 315/35R20 tires in the back.

I'll have to pick one of those gauges up for sure. I actually messed with my pinion angle some this weekend and my vibration got a lot better. My cv gap is good according to DSS. Measuring from my crankshaft pulley I got 89°. I then measured from the bottom part of the pinion flange (which sucks like you said) and got 89° there as well. I set my pinion to 90° and test drove it and the vibrations were practically gone. I suspect the remaining vibration around 2000-2200rpm is from the poly motor mounts because that occurs in neutral as well. Thanks for the info man.

Sent from my [device_name] using the svtperformance.com mobile app