Results 1 to 7 of 7
  1. #1

    Default Driveline vibrations at high speed

    Hey, long time no post, but I've got the capri on the road with the roller 302 and t5, 8.8 rear. I'm running the stock shaft from the 4 speed and the 7.5 with the current setup.

    I'm experiencing driveline vibrations above 50 or so. It gets worse the faster you go, and the clutch in or put at any rpm does not affect it. So we are looking st output shaft of trans to tires for an issue.

    I have rebalanced the tires, the u joints don't seem obviously loose, and there's nothing blatant staring at me.

    I'm thinking it's driveline angle or the shaft is just out of balance.

    I understand the U shape angle these fox's come with, but I dont really get what's acceptable for angles and the tremec app gives you angles but does not work for non z type angles.

    So my output is around 4-4.5* down
    Driveshaft is around 3.5-4* down (it is slightly different from the angle of the output shaft)
    Pinion is around .5-0* pointed down (toward the ground)

    So we have a u shape, but what do these angles equate to?
    I have all stock everything from the control arms to the crossmember and trans mount (4speed mount on the t5).

    Any help is appreciated so I don't go pulling driveshafts for no reason and still have the angles off.
    1979 Capri RS 302/4spd- Rough (but free!)
    1982 Fairmont 200/c5- Rough, but running
    1987 Olds Cutlass 403/t56/4.10 Dana 60
    1972 Plymouth Satellite wagon- AACA HPOF, all original, my grandpa bought it new.
    And many more...

  2. #2
    FEP Senior Member
    Join Date
    Mar 2008
    darien il


    According to Currie, the average car crafter should strive for between 1 and 3 degrees between the tailshaft of the transmission and driveshaft, and 1 to 3 degrees between the driveshaft and pinion. Furthermore, the two angles should be nearly equal (between 1 and 3 degrees), but always opposite, with mine when i was chasing the vibration, i also replace the drive shaft to the aluminum. that and other things finaly got it.

  3. #3


    Sounds like a bad u joint.
    1984.5 G.T.350 5.0 CFI AOD Convertible (TRX package, loaded)
    K&N filter in a stock dual snorkel, GT40 heads, Edelbrock 3721 intake, MSD 8456 Dist., MSD 8227 coil
    Comp cams XE254H, hypereutectic pistons
    Hooker Super Comp Shorty Equal Length Headers, catted BBK H-pipe, full custom duals
    Maximum Motorsports caster/camber plates and strut tower brace, 3.73 rear.
    Ford Performance Springs, Firehawk A/S 225/55r16 on LMR TRX r390 wheels (street)
    Federal 595 rs-rr 245/40r17 and 255/40r17 on OE cobra r wheels (race)
    AOD rebuilt with a 6 clutch direct drum, Koline steels stacked with 8 clutches, Kevlar band, superior shift kit, new torque converter. --Everything else stock and fully functional.

  4. #4


    The equal and opposite is what I've always done. But from all my reading, the nose down pinion I'm seeing on this car is normal for a fox body and acceptable. I'm just not sure how exactly I'm supposed to set this up to work.

    As for the joints, they aren't new but I see no noticeable slop in them. It is a stock shaft but I didn't have any issues before I changed literally everything around it.
    1979 Capri RS 302/4spd- Rough (but free!)
    1982 Fairmont 200/c5- Rough, but running
    1987 Olds Cutlass 403/t56/4.10 Dana 60
    1972 Plymouth Satellite wagon- AACA HPOF, all original, my grandpa bought it new.
    And many more...

  5. #5
    FEP Power Member 87gtVIC's Avatar
    Join Date
    May 2009
    Whitestone, NY


    Will mention u joint as well. Had a faint sound and vibration at higher speeds. Front u joint had one dry cap. That was enough to cause some noticeable vibrations. It had no slop but was very stiff because of no grease in the cap. Not too hard to just check them. Pull shaft out and if there is any rough spots while manipulating the joint you have an issue.

  6. #6
    FEP Member
    Join Date
    Jan 2016
    South Central Ohio


    Had a similiar vibration with mine with only 61K miles on it. swapped out to a swap meet aluminum shaft, vibration gone. Noticed that the stock ujoints were stiff, either dried up, or had a rough spot contributing to the vibration.

  7. #7
    FEP Super Member bwguardian's Avatar
    Join Date
    Jul 2010
    Houston (Clear Lake), Texas


    I'll also say u-joints. If you have a dry cap or two, they were used to only moving a certain amount which is why you didn't have issues before with the other setup. When you removed and re-installed it the joints were moved further out of the ordinary causing friction and/or your vibration. They will also feel tight with no slop but don't have the range of movement.

    Just went through this on my F350 4x4 and wound up also having to rebuild the cardan joint in the front driveshaft...boy was that a pain...and the carrier mid support for the split back driveshaft. I originally found two dry caps on the front driveshaft, but everything was tight.
    '82 GT monochromatic (red) cloth

    '85 GT vert two tone (white on charcoal)...white leather
    '00 F350 two tone (white on silver)...gray cloth
    '00 Excursion Limited two tone (white on tan)...tan leather...wifes ride
    '08 Taurus Limited ice blue...tan leather...daughter ride
    '08 Edge Limited white sand tri-coat metallic...tan leather...other daughters ride

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts