Probably so. I know I had to redo my trans mount with the 1/2" lower motor mounts.

I have a t5 with a cross member from Mustang Steve. I will pull the drive shaft and get data this weekend.

Yep!! Getting  your shaft at the right angle can be very rewarding!
Too severe angle can get you a lot of vibration as you increase speed.
Too mild angle can be bad also when you try getting up to speed.
Near zero angle  is what you should push for. It would also insure full engagement of the splines without hitting bottom when  hitting a bump.
Near zero angle will definitely put you in the "sweet spot" when you start driving it full speed.
A little side-to-side is acceptable if not at too severe angle.
Everybody concerned will be happier  when your shaft is operating  full speed at the optimal angle. 

Rough measurments with out pulling the drive shaft. Motor 3 deg down based on oil; pan rail . rear end 1deg down based on bottom of houseing. Drive shaft 1 deg down.
 Also noticed slight interferance with belly brace to oil pan.  Removed brace and cleranced.

Last edited by Steve-G (11/18/2015 7:49 AM)

GPatrick wrote:

To clarify the rear-end reading - is the housing "down" 1 degree towards the rear?  That would indicate a pinion "up" condition which is where it should be.

Really?? I would Say since the Pinion is Inside the Housing, if the Housing Top or Bottom is on a downward angle - Down when facing the Engine, then the Pinion is Pointing Downward Also.
I do Agree that some drivetrains allow for Trans down 3* and Pinion Up at 1*...

Last edited by Mach1_Ron (11/18/2015 1:08 PM)

I was hoping that it wasn't pinion down as that gives you a 4 degree difference.  A more exact reading on the pinon flange is in order.  What is the setup of your rear end?  Stock 8 or 9", a conversion, or real tired springs?  Also, was the car at normal ride height front and rear when the measurements were taken?  And, is the rear lowered somehow with blocks or other means?  Wedges may be in order or if it is a conversion, the spring perches may not be correct for the Mustang and they can be re-welded but shims/wedges may be all that you need to get the nose up about 3 degrees from where it is if the 1 degree down reading is correct.  But still - good news!  you don't need to lower the trans!  I guess one other thing to check is your driveshaft length.  I don't know when you swapped what but if the driveshaft is too long it may bottom in the trans and force the pinion down.  Pretty remote possibility but stranger things have happened.

Mach1_Ron wrote:

Steve-G wrote:

pinion down. Oposite of the way I understand it sould be .
 

If you end up deciding to go with Wedges, ping me. I had them on mine before the 4 Link swap. Learned a lot about the way they should be put in and which ones to buy and ones to avoid.

Wanna share?!
 

6sally6 wrote:

Mach1_Ron wrote:

Steve-G wrote:

pinion down. Oposite of the way I understand it sould be .
 

If you end up deciding to go with Wedges, ping me. I had them on mine before the 4 Link swap. Learned a lot about the way they should be put in and which ones to buy and ones to avoid.

Wanna share?!
 

The shims I ended up using, were the type that you run the Bolt, that Bolts the Leaf Springs together, thru the leafs and the wedge. This way you don't take a chance that the Wedge can move around. The other types, like Some places sell, just sit on top of the Bolt head that bolts the leafs together. That has the risk, slight as it may be, of letting the wedge move and possible come loose...and you don't want that to happen. On my first attempt, I thought I'll just undo 1 end of the leaf, undo the bolt, take it out, put on the shim and bolt everything back up... Not a good idea as things shifted on me. After taking it out, lining everything up and getting it buttoned back up... I took the 2nd leaf out of the car, put a couple of U Clamps on it, tightened them up, then unbolted the bolt, put on the shim and bolted everything back together much easier. I also had my Trans down 3* and used 2.5* shims, worked out very well for me.

Last edited by Mach1_Ron (11/19/2015 8:55 AM)

I got mine from 4X4 Parts... They happen to be right down the Street from me. But they know the stuff about Pinion Angle stuff. I looked at the ones from Speedway and Summit, but they are the type that just Sit on Top. I also had to get New Bolts for the Shim/Leaf Pack and trim to length once I got it all bolted up. 

Steve G, if you run it and there is no problem, you have saved yourself a lot of time and trouble.  Moving the mid section of the engine down a half inch may not be enough to cause a problem.  Or, it may be.  Run it, see if it is a problem, fix the problem.  Otherwise, drive it and enjoy!

Steve-G wrote:

Drove the car several times before the motor mount swap but not on the hyw. Didn't notice any unusual vibration. Now has a vibration. New mounts are urethane .

I think you found your Vibration. Urethane Mounts are going to make you feel more of the Engine Vibration than Rubber ones. When I first put in my T5 I used a Urethane mount and it about shook the car apart...lol. Replaced it with rubber and the vibration was Significantly less, then once I got the angles right..I'm good. Sounds like yours may just be the New Mounts.

I don't know the history of your car and upgrades and when they were done.  Are you running the original driveshaft or did you have to get it shortened with your T-5 swap?  Was it balanced?  As suggested earlier, it would be helpful to do a comparison of the car accelerating at a speed where you feel vibration followed by coasting in neutral through the same speed range and then a 2nd or 3rd gear deceleration again through the same speed range.  Under load/pulling, the nose of the pinion will lift and reduce the angular difference and potentially reducing the vibration you feel at steady speed.  Under deceleration the angle difference will be at its worst and the vibration should also be worse.  Without a device that measures frequencies, it is often hard while sitting in the car to know if you are feeling vibration at 2X driveshaft speed which is caused by a misalignment of the u-joints from the different angles or 1X driveshaft vibration due to unbalance.

For another test to make sure that you aren't feeling engine vibration rather than the driveshaft, do a speed range test in 3rd gear, 4th gear, and then 5th.  If it is the driveshaft, the vibration versus speed will be the same.  If the vibration is changing depending on engine speed you may be noticing some flywheel/pressure plate unbalance or even the damper.  Loose pinion bearings in the 8" can also produce a driveline vibration since you creating an eccentricity at the pinion causing a driveshaft runout.

There was a thread back a few months ago where the problem was finally traced to the output shaft of the transmission and that would be road speed and not engine speed related.  You don't have extreme driveshaft angles that would approach the limits of the u-joints.  What length output shaft sleeve are you running?  A short splined sleeve may have a greater tendency to wobble due to limited engagement into the trams.  A worn output shaft bearing can also induce vibration.  If the trans was fresh/new/rebuilt these are less likely to be problems but if it was a used car take-off, you may be feeling the effects of wear.

Urethane mounts don't produce vibration but they do transmit vibration more efficiently into the frame and passenger compartment.  Replacing them with rubber won't solve a vibration problem, you just won't feel it as much.  Sound and vibration "pathing" in a car is difficult because a vibration in the engine may come up through the transmission crossmember and a driveshaft vibration may come through the engine mounts into the frame.  This means that where you feel it or where it is loudest may not be where the vibration source is.

Long and short, it would be nice if you could turn the nose of the pinion up 1/2 or 1 degree but I would suggest that you do the driving tests first to confirm that it is really the driveshaft and not something else.  Or, I'll bring some equipment to the bash and we can do some testing.