The OFFICIAL clunk/thunk driveshaft thread (5 Viewers)

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My thunk has gotten to the point where I will spare no expense and go to the ends of the earth to fix. Re-greasing was making it better, but not completely solving it. However the rear was re-greased about two months ago and now it is thunking worse than ever.

About 18 months ago I had the u-joints replaced but that didn't fix it at all. My less than trusty dealer says to replace the driveshafts and some "control arms"? will cost about $1,600.

If I am not completely senseless, the thunk is definitely coming from the rear.

What steps, short of replacing everything, can I take to once and for all fix this very irritating issue?
 
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Put it in park and jack up a rear wheel. Turn it by hand. Hard. A *normal* one will have some slack. If you can flop the wheel back and forth, then you know something's up in the driveline. If you get under the truck (with jack stand in place) and get someone else to move the wheel, you might be able to isolate where the clunk comes from. You can try different stuff like holding the driveshaft while moving the wheel to see if it's in the rear end, or grab the driveshaft with all four wheels on the ground and trying to turn it to see where the slack is. It's a crap shoot on what it can be, so you just keep going until you find it...
 
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Could be something worn/loose, or could still be the infamous rear driveshaft slip joint thud.

Does it happen mainly upon starting to accelerate from a stop/idling/Drive? (As in starting to accelerate when the light turns green?) If so that is the symptom of The Thud.

Rear driveshaft slip (spline) joint must be OVERgreased until grease spooges past seal using MOLY grease. If it is not overgreased, and/or if a non-moly type grease is used, The Thud will not be alleviated.

Since both of the above shortcomings (not overgreased, not moly grease) are likely at your typical shop, it is likely that your thud may still be The Infamous Thud.
 

hankinid

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Rear driveshaft slip (spline) joint must be OVERgreased until grease spooges past seal using MOLY grease. If it is not overgreased, and/or if a non-moly type grease is used, The Thud will not be alleviated.

Since both of the above shortcomings (not overgreased, not moly grease) are likely at your typical shop, it is likely that your thud may still be The Infamous Thud.
At Tinkerer's suggestion, I greased the crap out of both front and rear slip joints a month or so ago...used Sta-Lube moly grease in the black cartridge. I greased until I had fresh stuff past the seals. Clunk gone. For the time it takes, slip joint and u-joint lube is now on the list at the same time as oil & filter change.

Thanks again Tinkerer:clap:

Steve
 
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Abbotsford
I love how you spelled "driveshaft" in your heading :D
I also have the infamous clunk every time I accelerate from a stop. Had it greased, came back after a couple thousand miles... Oh well, guess I have to live with it, lol!
 
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Austin, TX
I used to ask the dealer to lube with every other oil change (I get free oil changes for life at my dealer, so why not go there) and they lube the shafts for free ;)(if you ask). Still had the thunk, so I went and bought a grease gun and the moly grease, greased the heck out of it, and the thunk is finally gone!!! Its been a little over 5000 miles, so I guess we'll see if it comes back. Now if I can just get the ticking manifold gone...that'll be a little more expensive.
 
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I need to look at mine...mine only thunks if I let off gas while on highway and then push it back down after coasting a bit... guy in my club that has his own Lexus Toyota shop says it is the slip yoke. So going to try and grease mine up too....

Can they be greased TOO MUCH like some other items and cause it to form a vacuum and lock it up....like hubs will do if you put too much in them? Guessing the zerk is right on the yoke?
 
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For me, switching to synthetic grease is what finally cured the thunk. I have not had it now for 95K miles, but it was contsant before switching to synthetic. I grease at every oil change, which I do with sythetic at 5000K intervals.
 
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Jun 22, 2006
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Ok, crawled under the truck to liberally over grease, however my zerk seems to big for the fitting. I have replaced the u joints and my mechanic has been telling me the grease fitting is smaller than the standard fitting, and it appears as if it is. My grease just shot out all over the place - none of it going in.

I did go one auto store and they said there is only one size - the only thing that varies among greasing fittings is the thread size.

Anyone know if there is a smaller size?
 

bluecruiser

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I just used the size that came on the gun from the store. It is hard to get on, but it fits, no mess.
 
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Gleneagle, CO
Inside the U-joint it's easy to not get the grease coupler (gun side) all the way on the zerk (truck side) because the coupler is getting jammed against the sides of the joint. This causes grease to go all over. You need to position the front U-joints so that the zerks are pointed directly down to get the best access.
 
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^^ X2. I found mine a PITA to get to and I had to use one of the one handed grease guns with the tiny little grease tube versus the regular size but was able to get it on and greased the hell out of it, to the point of wanting to check the cab to see if I was filling it up!
 
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I took it back to guy who installed the u joints and the zerks size is smaller than standard - he is order a new gun adapter for me.
 
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So my mechanic got the adapter for a grease gun that fits these tiny grease fittings. He showed me one of these fittings that hadn't been installed - it's not threaded but meant jut to be hammer in. And, it has a tiny opening - really just a little ball that is pressed in when you squirt grease into it.

Well after a liberal greasing using moly, the thunk is gone. We didn't pump grease into the joints until grease excreted as my mechanic thought we could break the seals - is this really a risk?
 
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I'm no expert, but I've seen the topic come up multiple times and I know what the FSM says.

There seem to be differing opinions on the threads I've read and you'll see 2 extremes - either people claim you break the seal if you overgrease or you'll see people say the only way to know you have enough grease is to see it leak out. The people who claim overgreasing is bad say the best thing to do is remove the zerk and let the excess grease leak out that way.

See https://forum.ih8mud.com/100-series-cruisers/378824-too-much-grease-drive-shaft.html as an example.

See https://forum.ih8mud.com/100-series-cruisers/281147-mobil-1-synthetic-grease-nlgi-no-2-a.html as another example.

The FSM states the following (for 05 lx470) in the propeller shaft assembly section (PR-7):
HINT:
After installation, pump MP grease into each fitting with a grease gun until the grease begins to flow around
the oil seal.

I'll point out that under the FSM MA-10 for maintenance and lubricating the propeller shaft, it does not state that the grease should flow around the oil seal.

If we wanted to read into the FSM like it was the bible, I'd interpret that upon initial installation the grease should flow out but upon subsequent (normal) maintenance lubes, no need. It also doesn't warn in the FSM about overgreasing. Furthermore, I think everyone would agree that overgreasing the spider joints isn't a problem, just overgreasing the yoke is the debate...?
 
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For whatever it's worth (I'm no mechanic and I'm not even an avid/skilled DIY'er), I spoke to a guy at TLC in Los Angeles (I believe they're pretty respected LC specialists) and he was in "the grease until it flows" camp.
 
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This was discussed so much in the 80's section it's ridiculous. I think the general consensus there is NOT to over grease the driveshafts. Clunk stops because of the added pressure from over greasing the shafts....NOT GOOD. I've heard it argued so much I just make sure the driveshaft isn't over greased and say let the b*tch clunk if she wants to.
 
Joined
Jun 10, 2006
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Abbotsford
I have two left feet when it comes to mechanical stuff (except I can do pads and rotors and oil changes and stuff). I don't really know where to start with this, but I wanna fix my clunk. It went away for about 5k miles after the dealer greased, but charged me too much for it, and now it's back :(

Anyway, with lubing the driveshaft does anyone have any pictures that show EXACTLY where and how to lube the d-shaft? Remember, I'm a total beginner with this stuff, but I know it must be really easy. Thanks for any help you can provide!
 

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