TW Double-Double?

helievacpilot

Well-known member
Mar 29, 2007
960
0
Denver CO
99D2. Sitting on 4.5 to 5 in of lift. Pinion corrected arms front and rear, but because the front springs looked like a comma, the front arms rotated the pinion angle down past parallel with the driveshaft. Now I'm chasing a vibe. Rebuilt front shaft, which helped a little, but didn't eliminate it. I'm thinking the angle is too much for the single u-joint. Double-double TW shaft in my future?
 

stu454

Well-known member
Dec 15, 2004
5,407
61
Atlanta, GA
No shit. This is one of the reasons that I try to talk people out of going with more than 2-3" of lift: it's a shithole spiral of doom.

Bill, I don't mean to single you out. Your post just caught me at the right (wrong) time.
 

DiscoPhoto

Well-known member
Jul 23, 2012
2,581
76
Vermont
Grab a double double then... it could be something else, but at least it'll rule out the shaft, as well as give you the opportunity to tell people you have a double double.
 

seventyfive

Well-known member
Jan 3, 2010
4,280
100
over there
I didn't need a double double with my D2. You shouldn't need one either.

Put some bias TSL's on it and groove them, you will never notice a vibration ever again....but when you do notice a vibration it will immediately be followed by a giant BOOM!

You're better off having a CV shaft made than installing a double double.
 

stu454

Well-known member
Dec 15, 2004
5,407
61
Atlanta, GA
:banghead: Note to self: No straight-forward answers while everyone is on their period.
Oh yea brah. Already have 33's.

Hah! You expected no-bullshit answers when you have five inches of lift on a Disco and are wondering why you have weird vibrations.

And why do you have that much lift and only run 33's?
 

seventyfive

Well-known member
Jan 3, 2010
4,280
100
over there
keep in mind a double cardan joint is also referred to as a CV joint, but I'm referring to a ball type CV. it would be more expensive than an off the shelf prop shaft but don't sacrifice reliability for price.
131_1101_03_o+131_1101_the_cv_driveshaft_solution+j_e_reel_45_degree_cv_shaft.jpg


But you really don't need it nor do you need a double double
 

helievacpilot

Well-known member
Mar 29, 2007
960
0
Denver CO
keep in mind a double cardan joint is also referred to as a CV joint, but I'm referring to a ball type CV. it would be more expensive than an off the shelf prop shaft but don't sacrifice reliability for price.
131_1101_03_o+131_1101_the_cv_driveshaft_solution+j_e_reel_45_degree_cv_shaft.jpg


But you really don't need it nor do you need a double double

Exactly what I thought you were referring to. The reason I am even considering a double-double is that I have eliminated the other possible culprits. T/C output bearing, diff input bearing, worn u-joints etc.. Also, my pinion corrected arms rotated the pinion angle down beyond what is considered ideal for the dc driveshaft. I have also removed the front driveshaft altogether to confirm it's the front.
Having the arms re-worked is also not a option at this time. Right after I installed them, I was diagnosed with a serious medical condition that kept me sidelined for almost a year. Just now sorting issues on the LR. Last thing I want is to shell out almost 600 bucks for a new driveshaft, but not sure I have any other options?
 

seventyfive

Well-known member
Jan 3, 2010
4,280
100
over there
were the arms lengthened as well or just cranked? That's moot now, just strange they wouldn't be stretched as well.

I have no experience with double doubles but that's introducing more moving parts and shortens the shaft. Maybe frank will chime in.
 

helievacpilot

Well-known member
Mar 29, 2007
960
0
Denver CO
were the arms lengthened as well or just cranked? That's moot now, just strange they wouldn't be stretched as well.

I have no experience with double doubles but that's introducing more moving parts and shortens the shaft. Maybe frank will chime in.

They were stretched and cranked. My understanding is that the pinion angle should be as close to parallel to the driveshaft as possible for a standard dc. Because of the lift (I know, I know) the springs were bent into a "c" shape. To aleviate this to an extent, the arms rotated the diff down past parallel to the driveshaft. Eliminating all else, I am concluding that the resultant angle is too much for the single u-joint at the diff.
 

DiscoPhoto

Well-known member
Jul 23, 2012
2,581
76
Vermont
A guy locally that had a 5-6" lift on his D2 ran a double-double when he was having these issues, seemed to solve it the vibration for him.

Then again... you're running 33s which probably looks funny on a 5" lift. He was running 35s and probably could have gone larger
 

Mongo

Well-known member
Apr 19, 2004
5,731
2
59
driveshaft 101:






so the pinion is pointed down…even a a double-double isn't going to fix this
 

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