U-Joint Question - Part 2

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Divenut

Divenut

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Hey Folks,
As noted in a previous thread, I developed a vibration that only manifests itself when accelerating/under load. Was testing a new tune, hammered it hard in first, hit 2nd very solid at 6k, hooked great with no wheel spin. Coasted to a stop. Then noticed a subtle vibration when accelerating up to 60mph. Most pronounced between 45 and 65 mph.

I figured, u joints were the culprit. This morning I got the car up on stands to pull em and measure for replacements. I was expecting to find some play and/or visible damage, but other than being filthy and caked we crud, they appear tight, rubber in good shape etc...

So my question, has anyone experienced a problem witb u-joints that showed no visible damage? Would bad bearing caps cause similar symptoms? Also, hearing a "chirp" that sounds like a loose belt when letting off in 1st (sometimes in 2nd) after vigorous blips. Belt is tight.

Thought I'd ask members with more experience than me before digging into the ujoints.

Car is a 72 Duster 340, 727 w RMVB, 742 rearend.

Thanks as always,
Pat
 
Last edited:
Divenut said:
Hey Folks,
As noted in a previous thread, I developed a vibration that only manifests itself when accelerating/under load. Was testing a new tune, hammered it hard in first, hit 2nd very solid at 6k, hooked great with no wheel spin. Coasted to a stop. Then noticed a subtle vibration when accelerating up to 60mph. Most pronounced between 45 and 65 mph.

I figured, u joints were the culprit. This morning I got the car up on stands to pull em and measure for replacements. I was expecting to find some play and/or visible damage, but other than being filthy and caked we crud, they appear tight, rubber in good shape etc...

So my question, has anyone experienced a problem witb u-joints that showed no visible damage? Would bad bearing caps cause similar symptoms? Also, hearing a "chirp" that sounds like a loose belt when letting off in 1st (sometimes in 2nd) after vigorous blips. Belt is tight.

Thought I'd ask members with more experience than me before digging into the ujoints.

Car is a 72 Duster 340, 727 w RMVB, 742 rearend.

Thanks as always,
Pat
Click to expand...
Ck your tires could be something simple as small bulge in the tire
 
FWIW, I lost a driveshaft once because the pinion yoke had apparently spread a bit and the u-joint was able to hammer it more side-to-side. Went to billet pinion yokes after that.

I would see if the u-joints had any play while installed, rear on jack stands and in neutral. Just to make sure, remove the driveshaft to see if there are any tight or rough spots when you rotate the trans end and rear u-joint caps.

U-joints usually don't show visible external signs of impending failure.

Good time to check the pinion/driveshaft angles.
 
Divenut said:
So my question, has anyone experienced a problem witb u-joints that showed no visible damage? Would bad bearing caps cause similar symptoms? Also, hearing a "chirp" that sounds like a loose belt when letting off in 1st (sometimes in 2nd) after vigorous blips. Belt is tight.

Thought I'd ask members with more experience than me before digging into the ujoints.

Car is a 72 Duster 340, 727 w RMVB, 742 rearend.

Thanks as always,
Pat
Click to expand...

I have seen them look just fine on the outside to find a rusty pile of little busted up needles inside and not even be loose.
That's why I suggested U joints in your other thread, and now your making me do it again. :D LOL
 
TrailBeast said:
I have seen them look just fine on the outside to find a rusty pile of little busted up needles inside and not even be loose.
That's why I suggested U joints in your other thread, and now your making me do it again. :D LOL
Click to expand...

Lol! Ya figured u-joints might be the culprit. But you know how it is Beast, fearing the worse had me second guessing myself. Just that in the past I'd typically find some play/wiggle in them. That said, I'll be dragging my butt under the car after work one night this week after work to get them pull off. Keeping them fingers crossed that's it's just the ujoints brother!

Be well
Pat
 
Check your engine and transmission mount (s).
 
Divenut said:
Lol! Ya figured u-joints might be the culprit. But you know how it is Beast, fearing the worse had me second guessing myself. Just that in the past I'd typically find some play/wiggle in them. That said, I'll be dragging my butt under the car after work one night this week after work to get them pull off. Keeping them fingers crossed that's it's just the ujoints brother!

Be well
Pat
Click to expand...

Ah what's the worst thing it could be?
Nothing that can't be fixed, right? :D
 
i have that chirp/ whistle noise on both demon and duster, demon never did it til trans was rebuilt, havent found the cause or a good answer on this site
 
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