Driveline "clunk" is back

[Stripermike]

Hey Guys,

Back again... well, in one of my last posts I was so pleased to have put to rest the driveline clunk in my 99 - I lubed the slip yoke with some marine grade grease and the problem "magically" went away - for about a week.

If anyone has an idea of how I might exact a more permanent "repair" I'd love to hear it. The thought of taking apart my driveshaft 50 or so times a year to lube my slip yoke doesn't appeal to me.

Since eliminating my "hesitation, bucking issue" I've been happier with this truck, but I have to say... the more I drive it, the more I feel like it's a mere shadow of my 95. Jeez do I miss it....

 

[Slammed]

I was told to just replace the yoke that the new one is a better design and doesn't clunk

 

[Stripermike]

Did it work?

 

[Slammed]

I haven't done it yet but 3 different mechanics told me that's how they remedy the clunk

 

[lesterl]

You used the wrong grease..... GM makes a waxy grease that doesnt feel like grease that you put in, did it to my 95 hoe 6 months ago, hasnt klunked since (my uncle gave me a tad of it - former GM mechanic untill a$$hat shut down his shop....

 

[Chaingun]

There is a service bulliten on this, the yoke was redesigned and plated with a better material IIRC, and it states in the bulletin not to grease the yoke as it can enter the transfer case and may cause damage.
I had a clunk when stopping and starting that I originally attributed to the yoke binding, turned out i had a cracked spring. After having that replaced it went away for a few weeks and came back louder. This time it was the Ubolts that i'd used to replace the ones i cut off swapping springs. I had failed to torque them correctly and the entire rear end was loose.

I've also heard of binding at the rear spring shackles too, so it wouldn't hurt to hit them with a bit of white grease too.

 

[Stripermike]

I read about the plated yoke - also about not greasing the front shaft yoke, the one that goes into the transfer case, but it seems pretty common that guys have been lubing the yoke on the rear shaft. I know that's where my noise is coming from because it went away for about a week or so after I put some marine grease in - it's back now though.

 

[lesterl]

Yeah, the rear shaft is what I greased and I drive mine pretty hard, hasnt had issue since, my uncle (gm mechanic gave me a few dabs of the grease to put on the splines and it works... felt like spreading a wax, not much of a grease.....)

 

[lesterl]

Found this doing a google search for a popping noise I have been having with my Chassis, thought I would share in case someone may find it useful...............

As the yoke splines wear, they bind on the output shaft. As you apply the brakes, the rear of your truck rises, which causes the slip yoke to slide out of the transmission extension housing a bit. Then, as speed decreases, the body comes back down, and the slip yoke slides back into the transmission. Because the worn splines are binding, the yoke doesn’t slide back into the transmission smoothly. It slides back in all at once, typically when the truck has come to a complete stop. That’s when it “clunks” back into place. Two-and four-wheel drive trucks do it, and it is maddening.

There are a number of fixes. First, your GM dealer has technical service bulletin that outlines a procedure and a special grease for lubricating the shaft splines. A technician removes the driveshaft, greases the splines and reinstalls it. The fix is good for about a year, when the clunk inevitably returns and you must return to the dealer to have the procedure done again. If you are handy enough to perform such a service, use GM grease part No. 12345879, which is available at dealerships and other outlets such as Summit Racing. Red Line’s CV-2 grease is another option.

GM makes nickel-plated replacement yokes to alleviate the problem in four-wheel drive models (part No. 12477702 for 1500; part No. 12477704 for 2500) but not for two-wheel drive trucks. If lubricating it doesn’t help, you can buy an OEM replacement slip yoke and have it treated cryogenically, which makes it more durable.

 

[Stripermike]

Thanks lester. I found a bunch of stuff as I was searching around about this as well - the marine grease I used lasted for a little more than a week, I found a posting where someone said they had used anti-seize and had good results for 6+ months. I tried that and had similar results as with the marine grease.
I don't get the banging when I come to a stop, only on take off, but it is pretty substantial and really annoying. None of the dealerships around me have the grease in stock, but I'm having some ordered and will try that before I spring for the new slip yoke. What the hell, I figure I've already had the driveshaft out twice, what's another time or 2. I know I don't want to be pulling the damn thing 40 or 50 times a year to grease it though, and I have to assume that the grease is going somewhere...... probably into my newly rebuilt transmission!

 

[lesterl]

hmmm.....

 

[IronMan4Real]

I went to dealer. Part number changed and new part number unavailable here in Canada. But they gave me free a handfull of grease he says they use in the shop for that issue.
Nice parts manager.
I am gonna try it this week sometime and see if it helps but the clunk seems to make scence

 

[IronMan4Real]

Clunk gone but for how long? Been a week now and ok.
What products have you guys used over the counter that have lasted a year or more?