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Lubing a truck's driveshaft

A few weeks ago my Corolla’s clutch MC failed quite spectacularly, and I had to drive my 48 year old truck to the parts store for a replacement part. It never rains but it pours of course. On the way to the parts store the truck started making a squeaking noise, repetitive, which I guessed to be due to some dryness developing in the driveshaft u-joints. Once the Corolla was back on the road, next I lubed the truck’s driveshaft. Here’s the problem: The lubing instructions for the truck say to lube the rear driveshaft in 5 places, but I could only find 4 places. It’s a two-piece arrangement, splined in-between. One u-joint at the rear differential end, and two u-joints (a poor-man’s CV configuration) at the transfer case end. The four lube points I found were:

  1. Spline joint zerk fitting
  2. Rear u-joint zerk fitting
  3. Most forward u-joint zerk fitting
  4. Next to the most forward u-joint zerk fitting

Any ideas for the 5th place needing lube?

The spline where they come together.

I think that’s number one in the list above. Or are you saying there are two places to lube the spline?

I have seen some with no zerk on that fitting & you would have to pull it apart to put the grease.on it sometimes even with the zerk not enough grease get’ on it. Also does the front shaft have two set’s of U joint;s?

Ok, I see what you mean. To your credit the instructions say the proper way to do this job is to remove the driveshaft and lube it on the bench. There’s a lot of common sense in that advice, as lubing it on the truck is a major pain. The u-joints do indeed have zerk fittings, but accessing them isn’t so easy, especially the front two. I have to use a needle adapter, and even then I had to file the needle so it had a flat spot before it would clear the stuff in the way enough to reach the fitting opening. Just to make things even more fun, I had to manually push the truck backwards and forwards a little while laying underneath to get the driveshaft at just the right angle to access the fittings, propping my leg against the rear wheel to hold it steady when it was just right … lol .

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That is the only way I could ever get it done right.

When I lubed the slip joint, grease came out the backside, but none ever appeared at the front. I think you are right, to lube the slip joint properly you have to remove the driveshaft, take the two pieces apart, lube each one, and put it back together. Not doing that may be why I’m having a bit a clunk when I shift from P to D. The instructions say to lube the rear leaf springs too, which I’ve never done. So next time I’ll do it the correct way, see if that improves the clunk problem. Even with the short-cut way I did it, the squeaking is gone, so that’s a good thing. And the clunk is significantly reduced.

I have heard about greasing the leaf spring’s but I have never done it & have never had a problem the only thing I have ever done was to use an old paint brush & put a lite coat of usded motor oil on them I would think if you was to put grease on them it would pick up a lot of dirt & crap.

The instructions say to lube the ends of the springs, not the entire length. Why do it that way? Don’t know. In fact I’m starting to think there may be a lot more things I don’t know than I do know … lol .

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You never get too old to stop learning.

You’re also never too old to discover another thing you never knew.

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If the truck is raised at the frame the axle will drop, extending the springs and moving the spacers at the ends of the short leaves away from their normal position. Applying a light coat of any grease to the normal contact spot should take care of the problem. A few shots of spray lithium should take care of the shackles while the axles is swinging also.

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Also known as a “Double Cardan Joint”, they have 3 lube points
Capture
or sometimes thru a hole in the center section
Capture1

There is also an often neglected center ball joint that needs lubed also
Capture

It sounds like you’ve got all the parts where things could move. Did the squeak stop?

If you heard a squeak and you have a clunk, you probably have a bad U-joint. Sometimes it is hard to determine which if any are bad while the drive shaft is in place. I would recommend removing the drive shaft and checking each U-joint, or just do a pre-emptive replacement of all of them.

The spline you greased, was that at the back of the transmission or in an expansion joint? If it was in an expansion joint, then the spline at the end of the transmission would be your fifth place, but it is usually done only when the drive shaft has been removed for other maintenance, i.e U-joints.

The easiest way to check for a worn U-joint is, jack the rear of the vehicle up so the rear tires are off the ground, place the transmission in neutral, and rock one of the rear tires back and forth while watching the driveshaft for a worn U-joint.

Tester

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If just the needle bearing in one cap got crossed up and self destructed, that may not ID the bad joint as the other three caps will hold the joint steady. But usually when one cap does that, the others have enough wear so that some movement will be visible. But it is hard to put the kind of strain on them with your hand as the engine puts on them when driving.

I did that on my Silverado once and they all appeared to be good. I did it because I could hear a slight clunk when shifting the transmission into gear. Didn’t see anything so I ignored it. A couple of weeks later, the transfer case adapter cracked at the end of the transmission. When I removed the drive shaft, then I discovered that both U-joints in the rear driveshaft were bad.

I’ve had bad u-joints before so know how they show play when hand-twisting on the drive shaft. I’m not seeing any u-joint play or movement, so doubt the squeaking problem is a bad u-joint. The lube fixed the squeak in any event.

Thanks for the informative photos, yes, that makes more sense, the 5th lube point must be that double cardan zerk, the middle one in your top photo. That one is not associated w/a u-joint. The manual refers to something called a “centering ball and socket”, which I presume is what center zerk lubes. I don’t recall ever lubing it before. I may have lubed it at some point when replacing a faulty u-joint on the bench though. The zerk fitting for the middle one must be a different type, more recessed, than the ones on the opposing u-joints. The u-joint zerks have a short stem that sticks up, while there’s nothing sticking up that I can see from the middle of the DC joint. I’ll clean that section up and see if I can find a recessed zerk fitting there.

A double cardon joint is difficult and few DIYers would have the tools to do it @George_San_Jose1. But you seem to be at the upper end of DIY.

How about a Master DIYer!

This vdo purports to show to rebuild a Jeep double cardan joint, and shows where the ball/socket assembly is located in relationship to the other stuff; I couldn’t see the zerk fitting for that part, but it seems like it must be the missing third lube point for the front part of the rear driveshaft.