That's my understanding too.
The OFFICIAL clunk/thunk driveshaft thread (1 Viewer)
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That's my understanding too.
I am no mechanic, but this make sense and is exactly how mine worked. I pumped it in until it flowed clean or "cleaner".
Then I attempted to clean up the mess. I did not clean as much as I should have as now I have a faint burning oil smell from it splattering around and hitting hot undercarriage.
The THUNK is GONE, so I am happy!!! Funny part is I have had the "Thunk" on a couple 4wd vehicles and didn't ever think anything of it, but once I read there was a fix I needed it gone LOL.
If you're not seeing grease at the end of the driveshaft seal, you need to clean the driveshaft.
Unlike a hydraulic or pneumatic cylinder, the ds is designed to release lubricant from the end with the seal.
I used a 20mm cannon cleaning brush from the local surplus store and a baby bottle brush with parts cleaner. Rinsed the clean parts with lacquer thinner dried with compressed air. I got great grease flow past the seal.
It's exactly the same as any other gizmo using a similar seal.
The spline joint is easy to clean, the u-joints not so much so. I "borrow" make-up removal pads from
and keep a stash in the garage for the u-joints. The LX still tosses a bit of grease on the underside.Steve
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This is basically what your driveshaft is like. It is a cylinder with a piston in it. When you fill it with grease, it becomes a hydraulic cylinder, full of incompressible grease. Go to a frame shop, look at the cylinders that are strong enough to twist your truck into a pretzel, they aren't very big cylinders. Do not fill the airspace in your driveshaft with grease, it needs to be able to compress, and if it can't it will compress something else.
I like the picture as it shows how the space can 'go hydraulic' if grease can't make it back past the seal, but I'm not sure I agree with the "Do not fill airspace in your driveshaft with grease" part. Please correct me if I'm all wet on this, but if the seal isn't all gunked up filling the cavity will grease is the only way to purge the old grease from the system?
My fear with this thread is that people are unwittingly turning their driveshafts into hydraulic rams. The 'thunk' goes away because the thrust takes away the slop in the input shaft that was causing the thunk sound. I don't think we're actually getting spline-to-spline thunk, are we?
Over time pressure is relieved and the thunk returns. The user re-greases and the thunk goes away. He is left thinking that it's a lubrication issue whereas it's actually improper maintenance putting a longitudinal load on differential bits not designed for such load.
If true, perhaps we should (a) embrace the thunk as part of a 'real truck'
and (b) do a better job of maintaining our drive shafts by performing a disassembly and cleaning if grease doesn't come out. I know I'm guilty of not doing the latter.Again, just a theory I have, please correct/update if wrong.
I theorized that my slip yoke was worn (from P.O. never lubing?) to the point that it clunked no matter what we did.
Solution: new rear propeller shaft. Bought it from CDan, had my mechanic put it on yesterday when the Hundy went in for an oil change. Early indications are that the clunk is gone.
I am going to clean the old propeller shaft and examine the slip yoke. I'll post up pics later.
Rigger
Solution: new rear propeller shaft. Bought it from CDan, had my mechanic put it on yesterday when the Hundy went in for an oil change. Early indications are that the clunk is gone.
I am going to clean the old propeller shaft and examine the slip yoke. I'll post up pics later.
Rigger
I havent lubed my drive line in 10k miles. No Thunk.
It finally disappeared when I replaced my rear control arms (stated earlier).
There is a variety of things that can cause the "thunk" not just drive line that causes it, though that seems to be the end point.
It finally disappeared when I replaced my rear control arms (stated earlier).
There is a variety of things that can cause the "thunk" not just drive line that causes it, though that seems to be the end point.
I think you're dead-on. The driveshaft assembly is NOT the same has a hydraulic piston...were it, it would be locked up all the time.I like the picture as it shows how the space can 'go hydraulic' if grease can't make it back past the seal, but I'm not sure I agree with the "Do not fill airspace in your driveshaft with grease" part. Please correct me if I'm all wet on this, but if the seal isn't all gunked up filling the cavity will grease is the only way to purge the old grease from the system?
My fear with this thread is that people are unwittingly turning their driveshafts into hydraulic rams. The 'thunk' goes away because the thrust takes away the slop in the input shaft that was causing the thunk sound. I don't think we're actually getting spline-to-spline thunk, are we?
Over time pressure is relieved and the thunk returns. The user re-greases and the thunk goes away. He is left thinking that it's a lubrication issue whereas it's actually improper maintenance putting a longitudinal load on differential bits not designed for such load.
If true, perhaps we should (a) embrace the thunk as part of a 'real truck'
Again, just a theory I have, please correct/update if wrong.
If grease doesn't show at the outside end of the seal, either disassemble the driveshaft and clean it thoroughly, and / or replace the seal.
Steve
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Hey guys, quick question: Is there a specific grease gun/fitting that is needed or will any ol' one work for the driveshaft? If so, where would I find it? Want to get stuff ordered ahead of time, including the grease etc. Maybe someone has a quick "shopping list" of what is needed to do all of the above, that would be great.
Thanks!
Thanks!
I use either an air-powered grease gun or one with a pistol grip...standard zerk fitting on the end of a flexible hose to the gun.
That should be all you need.
If you plan on driveshaft disassembly, you'll also need sockets and wrenches to remove the shafts and solvent and brushes to clean the shaft ends...
Steve
Thanks Steve, I'm not planning on disassembling just lubing up. Only reason I asked about the zerk fitting is because I've seen some comments on improperly sized fittings not getting the job done. I'll definitely go with a standard pump gun this time around and see what I can find on proper lubricants, thanks again.
You're welcome.
I use Mobil 1 or Valvoline Synthetic grease...NGLI #2 per the FSM. Good point about fitting size...fittings are standard zerk, but look for as small an O.D. as you can find for the gun end...clearance on some gun ends may be too large to mate correctly with the u-joint zerks due to lack of clearance caused by the u-joints...hard to explain but you'll see what I mean if you rotate the shafts to have the zerks point straight down.
Steve
The last two posts would benefit from an answer. I too have these issues. My mechanic says "clunk" is from inside TC but can't say why, so I want to do a double DS service first to save dropping the TC. Is there a detailed write up of how to do the DS service?
Get a new mechanic! He is just trying to make $$$. You can drive with the clunk forever. Just lube your driveline every 5 k miles. No one on this forum even with many hundreds of thousand miles has been required to replace anything related to driveline clunk because of failure. Lexus has replace because of customer satisfaction, don't want a big ass 4x4 SUV feeling like anything but a luxury vehicle
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Guys, need a quick answer here as I'm trying to get this taken care of ASAP so I can head back home.
I bought a tube of moly and a tube of the NLGI-2 and spent WAY too much time pumping the moly in with nothing coming out past the seals. How many pumps of a typical Autozone grease gun should it take before grease starts going past the seals? I took apart the gun and everything seems to be flowing correctly but I was under there for a good 15-20 minutes pumping with nothing coming past the seals...something can't be right.
The zerk fitting seems to click into place nicely on the fitting, and it feels like there is some pressure in the gun, but I'm at the point where I think the gun must be faulty and I need to grab a new one. I could be an idiot and just not know how to operate a grease gun, but I think I've tried just about everything, including screaming obscenities at it
Help would be appreciated guys!
I bought a tube of moly and a tube of the NLGI-2 and spent WAY too much time pumping the moly in with nothing coming out past the seals. How many pumps of a typical Autozone grease gun should it take before grease starts going past the seals? I took apart the gun and everything seems to be flowing correctly but I was under there for a good 15-20 minutes pumping with nothing coming past the seals...something can't be right.
The zerk fitting seems to click into place nicely on the fitting, and it feels like there is some pressure in the gun, but I'm at the point where I think the gun must be faulty and I need to grab a new one. I could be an idiot and just not know how to operate a grease gun, but I think I've tried just about everything, including screaming obscenities at it
Help would be appreciated guys!
Guys, need a quick answer here as I'm trying to get this taken care of ASAP so I can head back home.
I bought a tube of moly and a tube of the NLGI-2 and spent WAY too much time pumping the moly in with nothing coming out past the seals. How many pumps of a typical Autozone grease gun should it take before grease starts going past the seals? I took apart the gun and everything seems to be flowing correctly but I was under there for a good 15-20 minutes pumping with nothing coming past the seals...something can't be right.
The zerk fitting seems to click into place nicely on the fitting, and it feels like there is some pressure in the gun, but I'm at the point where I think the gun must be faulty and I need to grab a new one. I could be an idiot and just not know how to operate a grease gun, but I think I've tried just about everything, including screaming obscenities at it
Help would be appreciated guys!
When you pump it does grease come out? If not something is wrong.
. . . and is the grease not going into the zerk but outside and around it? If not, then the gun doesn't have a good connection to the zerk.
If it does and no grease is getting pushed past the seals, then keep pumping. You can usually hear it break the seals with a popping type noise.
If it does and no grease is getting pushed past the seals, then keep pumping. You can usually hear it break the seals with a popping type noise.
Yes, grease comes out when pumping, but sometimes the canister pops off during pumping.
No grease is coming out around the zerk fitting, and I have yet to hear the "pop" of grease going past the seals. To be clear, when disconnected, it does seem to pump fine, but I'm just trying to get a sense of how much pumping is necessary.
Typically, if its been a while since its had maintenance performed on it, then it may take up to 20 to 30 pumps. It doesn't take much - at least IMO - with the u-joints. Typically only 5 or 6 if its been a while. If you're still not getting any grease out, you may want to remove the drive shaft and take a look at it.
Yeah I definitely did more than 20-30 pumps, that I can be sure of. At least now I know it should be under 10 for the u-joints, so that's a good starting point. I can't imagine that I've pumped all of that grease in there with nothing coming out, so my gut is telling me that the grease is not pumping when the zerk is connected (and working when disconnected), aka a bad grease gun. I was focusing on the driveshaft so if there's a rough number of pumps for that I should keep in mind, that would be great.
I think I'm going to grab a new grease gun and go from there. If that doesn't work I'm going to take it to Mr. T and have them do it while I watch so I can see what should be happening
