The OFFICIAL clunk/thunk driveshaft thread (3 Viewers)

[RobRed]

The clunk phenomenon is really several things wearing that are causing the slack, not one specific ah ha item. For some the drive line lube fixes the issue.

After replacing both my CVs with fresh Toyota units my clunk has almost entirely disappeared. I'm talking about the same clunk that most experience where you lube the drive shafts and it disappears for a while. To your question, yes it could very well be diff induced.

As an experiment I have not lubed my drive shafts in about 5000 miles and the clunk is mostly gone. I used to have to lube the drive shafts every 1000 miles to get it close to being this good.

 

[DJWUZJ]

When in doubt, check your shocks too!

After pulling my shafts, and greasing by hand, that's all it turned out to be.

145k miles and clunk free with doing a few pumps until it purges every 5k miles.

 

[hankinid]

Where the heck are the splines, any pictures be greatly appreciated?

Thanks

Inside the shafts. You have to pull the shafts apart to see the splines.

Steve

 

[Quick]

What are the steps in lubing the shaft after taking it off? I was told you need to mark the drive shaft and also the splines but I just can't comprehend what they are talking about. Can some one care to explain the procedure?

Thanks

 

[phippsj]

Not true. Drop your shaft and clean it out. Lube by hand. I just did the same thing. It just creates a pile of grease on one end, with not path for egress past the seal. Not sure it provides for any grease to migrate to the splines, either. If your seal works properly (i.e. letting grease exit) then your logic is sound, but if the seal is jacked, then you're just limiting DS movement by pumping in grease.​

Ok. I pulled out the rear drive shaft and cleaned up the splines. Mainly cleaned the female splines since the male splines are mostly covered by the dust guard and seal.

After digging out all the old black dirty gritty grease and the tablespoon of newer red grease that I had pumped in on earlier lube jobs, I jammed a clean rag down into the splines several times until everything was shiney and clean. I didn't use any cleaner or solvent.

I then pumped in fresh grease up to the beginning of the splines and globbed a bunch on the splines with my finger. However, when I slid the splines back together, it was like compressing an air cylinder. The seal wouldn't let any air pass, so I pulled out the zerk and pushed it together squirting out most of the grease and some trapped air. I installed the zerk and pumped in more grease until the shaft was the right length to install. After bolting up both ends, I pumped in more grease into the splines but I couldn't get it to go past the dust seal. Maybe I need a pneumatic grease gun to get enough power behind it.

Test drove it and no clunks. I'm thinking it might come back at some point, so I'll try to pump in more grease. BTW, there wasn't a bleed hole on the back of the yoke.

Had to use an air impact gun to get the bolts loose, since they had never been taken apart. Not rusty, just really tight. Getting the torque wrench on all the bolts was a challenge. Now I see why real mechanics work on trucks with a lift.

I plan to do the front drive shaft in a couple of weeks when I install new sway bar bushings all around.

 

[2001LC]

No bleed hole in back of yoke from factory. But many shop drill one, but that's not to be spoken of ever. I used #1 grease until seals loosen-up, then revert back to factory spec #2. Don't jack up when greasing, keeps hydro pressure from extending to far.

 

[scottm]

After replacing the bearings on my 80 driveshaft, I've been very consistent in lubing my driveshaft. Mobil 1 MP in the spider bearings, moly/graphite grease in the splines. After someone cracked the transfer case by over-filling the driveshaft with grease, I'm very methodical about getting just a few pumps of grease in the cavity each time. My results were not good.

14mm nuts and bolts hold the driveshaft up. Mark the flanges so it goes back the same way. I needed a big cheater on a box-end to break things loose. The rear flange has bolts and nuts, you need two 14mm wrenches there. A ratchet wrench can fit with an extension.

Once on your bench or floor, mark the driveshaft so you can get the splines back together the same way they came apart.

 

[scottm]

Not a great pic, but there is no fresh grease getting from the zirc to the splines inside this driveshaft. Pumping enough grease in to push out through the splines would fill the air pocket and create a solid driveshaft, very bad. The grease that is in the splines feels like tar, not slippery. New grease should help things.

 

[SmoothLC]

So @scottm, how has this approach worked out on your rig?

This morning I greased all the spider and slip yokes, but had a heck of a time getting grease to purge the front drive shaft slip yoke.

Pumped and pumped but nothing.

So after they were all greased, I took the LC out for a spin and played around to get the drive shaft to shift.

When I got back home and got underneath, it appeared that did the trick.

Have you done anything additional since to address the problem (e.g. no grease getting from the zerk to the splines)?

Thanks.

 

[SWUtah]

So @scottm, how has this approach worked out on your rig?

This morning I greased all the spider and slip yokes, but had a heck of a time getting grease to purge the front drive shaft slip yoke.

Pumped and pumped but nothing.

So after they were all greased, I took the LC out for a spin and played around to get the drive shaft to shift.

When I got back home and got underneath, it appeared that did the trick.

Have you done anything additional since to address the problem (e.g. no grease getting from the zirc to the splines)?

Thanks.

If I remember correctly there are 6 grease zerts?

 

[hankinid]

Once on your bench or floor, mark the driveshaft so you can get the splines back together the same way they came apart.

Simple...FSM shows all fittings facing in the same direction

If I remember correctly there are 6 grease zerts?

Correct. One on each u-joint, one on each driveshaft.

Steve
.

 

[scottm]

I had forgotten about the clunk, it is gone.

 

[SALTY METHODS]

I greased mine and for the most part the clunk is gone.

 

[Norcalfamily]

Greae did the trick

 

[SmoothLC]

Funny . . . every time I grease the zerks and then go driving, the LC seems to ride incredibly smooth. (By "seat of the pants" feel of course.)

 

[Andres G]

So I had taken my LC to my Toyota dealership quick service lane, and had the guy grease the drive shafts the way they are instructed to do... It was clear to me that they have no idea how much grease was needed. The Clunk was cured for a couple of days but came back after that.

This morning I got myself a grease gun and a tube of grease and went to work on it. I remembered a post from here mentioning that after pumping so much grease into the driveshaft someone thought they were filling the inside of the cab with grease, and that was my case. I must have used about half the tube of grease on the rear shaft alone until grease came out of the rear seal. It was clear it had been empty as the grease that came out was absolutely clean. Same thing happened with the front driveshaft, but requiring much less grease to push thru.

As far as the U-Joints go, those took much less grease, but had the old and stinky black stuff in there (really nasty smelling and looking). This time, after a few pumps, the black old grease started flowing out and I kept going until the new grease started coming thru.

Went for a drive after that and it was immediately noticeable that not only the Clunk was gone, but the smoother ride described by SmoothLC up here appeared to be the case for me as well.

I took a pic of the grease flowing thru the seal on the back driveshaft, but will have to upload from the phone later when not on the fritz.

 

[scottm]

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.

 

[SWUtah]

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.

Right, 3 squirts every 5K miles

 

[OregonLC]

Isn't the issue that the splines get gunked up and effectively seal the grease from leaving the chamber. Typically you add grease until it flows clean back past the seal. Is this not the case with the splined portion?

 

[drwapenshaw]

Did mine today. Moly on Yolks and Lithium on spiders. Awesome info thread!