Meltor Posted February 3, 2012 Report Share Posted February 3, 2012 so after i got my truck towed home i noticed that my u-joint had sheared off. come to find out it was my third member. it shredded itself. found one at a junk yard and its a different ratio. but that is not my problem at the moment. i have it all buttoned up and drove it. at 30mph i get a pretty bad shimmy. i figure it is my driveline and i am confused as to what part is balanced. due to the u-joint shearing off i was not able to mark the position. do i need to remove the u-joint and rotate it or can i remove the yoke at the third member and rotate that until the shimmy goes away? thank you Quote Link to comment
]2eDeYe Posted February 3, 2012 Report Share Posted February 3, 2012 The shaft might be out of balance, in that case any driveline shop should be able to balance it. How does the carrier bearing look? This can cause a shimmy also. I would suspect the tires first, but if you broke the u-joint you may have twisted the driveline. Quote Link to comment
Farmer Joe Posted February 3, 2012 Report Share Posted February 3, 2012 im not following what you mean by "the unjoint sheared off." are you talking about the 4 bolts on the yoke sheared off? do you have a picture of the damage? did the drive line hit the ground when you were towing it? like redeye said, id check the driveline for being out of whack or anything else that spins... Quote Link to comment
Meltor Posted February 3, 2012 Author Report Share Posted February 3, 2012 2eDeYe' date='03 February 2012 - 10:19 AM' timestamp='1328293148' post='626195']The shaft might be out of balance, in that case any driveline shop should be able to balance it. How does the carrier bearing look? This can cause a shimmy also. I would suspect the tires first, but if you broke the u-joint you may have twisted the driveline. i do not have a carrier bearing. Quote Link to comment
Meltor Posted February 3, 2012 Author Report Share Posted February 3, 2012 im not following what you mean by "the unjoint sheared off." are you talking about the 4 bolts on the yoke sheared off? do you have a picture of the damage? did the drive line hit the ground when you were towing it? like redeye said, id check the driveline for being out of whack or anything else that spins... my third member locked up and caused the u-joint to break. the yoke is good and the 4 bolts that hold it on. the drive line did not hit the ground. how bad is it to drive this way? it is my only means of transportation. Quote Link to comment
Meltor Posted February 3, 2012 Author Report Share Posted February 3, 2012 this is the broken u-joint Quote Link to comment
datsunaholic Posted February 3, 2012 Report Share Posted February 3, 2012 The driveline is balanced as a unit. Moving position of the U-joint won't fix it unless by pure chance. Most likely the driveshaft is twisted, or the U-joint at the other end is damaged as well, or both. What broke one would highly likely have damaged the other, it's just when one failed the load came off. The consequences of driving like that are, at a minimum, you'll wear out the U-joints faster. At medium, you'll wear out the U-joints, and the output bearing of the transfer case and the input bearing of new 3rd member. At worst, the front U-joint will fail spectacularly, causing the driveshaft to pole-vault itself into the ground and/or whip around and tear the bottom of the truck up including the gas tank. That IS the basically worst-case scenario, but the longer you drive like that the more possible it becomes. Quote Link to comment
]2eDeYe Posted February 3, 2012 Report Share Posted February 3, 2012 That's a quality break :cool: Depends on how bad the vibration is. I would take the shaft in and have it checked to make sure it is still true and balanced after a break like that. I am assuming it did not vibrate before the u-joint broke. Quote Link to comment
Meltor Posted February 3, 2012 Author Report Share Posted February 3, 2012 2eDeYe' date='03 February 2012 - 01:12 PM' timestamp='1328303544' post='626279']That's a quality break :cool: Depends on how bad the vibration is. I would take the shaft in and have it checked to make sure it is still true and balanced after a break like that. I am assuming it did not vibrate before the u-joint broke. correct. no wobble before. i have an appointment to check the driveline. $55 to rebalance Quote Link to comment
Meltor Posted February 8, 2012 Author Report Share Posted February 8, 2012 driveline is all better. it was tweaked pretty bad. the gear ratio i had in my truck was 35:7 and now i had to put in 38:9 is this going to be a problem for me when i want to wheel? Quote Link to comment
flatcat19 Posted February 8, 2012 Report Share Posted February 8, 2012 You'll definitely being faster off the line. Top end will be lower speed. I could be wrong on this... 38:9 is 4.375 35:7 is the 3.889 720's are easier to find in the yards than most others. Find the one you want if you don't like your new set-up. On the plate in the engine bay, lower right corner it will say "HFxx" The "xx" is the gear ratio. That should make your hunt a bit easier. Quote Link to comment
datzenmike Posted February 8, 2012 Report Share Posted February 8, 2012 Those are not Nissan differential numbers. The front and rear diffs should have matching ratios, or close or the rears will be pushing the body into the front or the fronts wil be trying to stretch the body away from the rears. Not such a problem in mud where the tires can spin at different speeds but rough on tires and drive components on pavement. Quote Link to comment
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