Brother, can you spare a driveshaft?

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Hoosier Daddy

Hoosier Daddy

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I've got a funky vibe/rumble coming from the front of my 80. It goes away completely with the front driveshaft removed. New Toyota u joints made no difference. Definitely not dry spindles either. I can't detect any play in the pinion or TC output flanges.

Think my next step in troubleshooting is to try a different front driveshaft, to rule that out completely. Anybody got a good spare lying around or wanna let me borrow the one off their truck for an hour?
 
Might drive up to driveline service and have them look at the angles. With a CV front driveshaft, your bottom joint has to be within about 2 degrees of straight though. I remember we put those high offset castle correction bushings in your lower control arms, that may have thrown your angles out by clocking the pinion down too far. You can usually tell if your angles are wrong because when you put in new ujoints, the vibration will actually get a little worse.
 
Ha, yeah, I took it there. The young dude I talked to wasn't particularly helpful. He just wanted to argue that the u joints should be in phase. He got really hung up on that.

I tried it in-phase later and it made no difference. :doh:

Either way, the vib started well over a year after the lift and caster bushings. I'm thinking they are not related, but who knows...
 
On the gas - no vibration

Totally off the gas - no vibration

Just enough gas to prevent engine braking - there it is.

Seems like having a load on the drivetrain prevents the vibration. Unloaded, it vibrates.
 
black95 said:
Time to re-gear to 4.88's and buy some 35's :)
Click to expand...

Dude, you're joking, but I have already started doing some research on that... The boss likes big tires and I know she would totally go for 35's - but it would take some serious convincing to get her to approve that kind of $$$.

But first I have to narrow down where this vibe is coming from....

No idea whether the TC is chain driven.
 
I've seen a lot of threads on locker actuators getting gummed up and sticking, can they stick and keep the locker locked? Did this start after china wall? Just shooting in the dark now...
 
80 case is not chain drive. all gear. I would guess driveshaft angle too. Especially since it happened after the lift. I have the same issue in my 60. only happens in 4WD. If you had bad angles on the drive line it could cause other things to go wrong. It could be carrier bearings but I would think you would hear some kind of humming noise at 40 or so.
 
UPDATE - I received my Chassis Ears by UPS today.

LEAD ONE - transfer case - noisy just in general, with some very minor whining noise, and a moderate amount of the vibration noise
LEAD TWO - front differential - very quiet in general, but this is where I heard the vibration noise most distinctly and loudly, although the difference was not huge.
LEAD THREE - passenger knuckle - very quiet, but heard the vibe a moderate amount
LEAD FOUR - driver knuckle - very quiet, but heard the vibe a mild amount (less than passenger side)
LEAD FIVE - t-case crossmember - very quiet, barely heard the vibration

With the Chassis Ears, I have discovered the vibration occurs as low as 18 mph, although you can't hear it with the human ear until around 40 mph.

Unfortunately I could hear the vibe all throughout the front drivetrain. However, I believe this test generally narrows it down to the front differential. I had to put the diff lead right on the pumpkin because there was no good place to attach it near the pinion flange. I would assume the passenger knuckle transmitted the vibe more loudly than the driver side because the passenger side is closer to the diff.

My next steps are to Drain and Refill the front diff, looking for metallic debris.

I would still like to try another front driveshaft just to be sure it's not a defect with my driveshaft, so I'm begging again if anyone will let me borrow theirs briefly....
 
Hoosier Daddy said:
UPDATE -

I would still like to try another front driveshaft just to be sure it's not a defect with my driveshaft, so I'm begging again if anyone will let me borrow theirs briefly....
Click to expand...

Brad,

You can borrow the one off of the 96 I bought, if it will work for you. I have the motor pulled at the moment and parts still need to go get machined, so it's not going anywhere. I have family in town till Tuesday, so it would have to be after that. I'm sure you would like to do it this weekend, but, beggars can't be choosers! :flipoff2:If you can't find another one by then let me know.
 
Hoosier Daddy said:
I would still like to try another front driveshaft just to be sure it's not a defect with my driveshaft, so I'm begging again if anyone will let me borrow theirs briefly....
Click to expand...

You can try mine today if you like. Though I am not in a position to help much. pm phone number.
 
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