Drive line "clunk" repair...

[Unit453]

Grady (Saratoga) and I did some maintenance today and started with my driveline clunk that's plagued my truck since it was new. I've had it relubed 3 times or so and it keeps coming back. Today, it was time to do it ourselves.

Mobile 1 synthetic grease since evidently, the GM stuff is pure garbage.

We unscrewed the 4 bolts holding the shaft into the rear end and dropped the shaft. Next we pulled it out of the transfer case. We then inspected the yoke to see why this problem is happening to so many trucks.

For one, it was bone dry. Not a drop on it, nothing, nada. It was piping hot. Hot as in we couldnt touch it for more than a few seconds. I have no idea if this is normal or not.

I tried to sand off some of the rust that's accumulated on it to smooth it down a bit.

I wanted to put generous amounts of lube on the splines. I dont want this to happen for a while so I put ALOT of grease in there.

Crawl back under there, insert the yoke back into the transfer case and then button back up the shaft back to the rear diff. Lets hope this works and stays good for a while.

Thanks to Grady for letting me use his garage and for the two bottles of water, not to mention the labor. All in all, good day worth of maintenance.

Now, I'm curious to know why that yoke was so damn hot. You can also see that it is starting to show signs of discoloration from the heat. I dont know if this is normal or not.

And I didnt realize just how much rust was under there thanks to northern NY winters.

 

[JiFaire]

Hey Nick - same thing happened with my Dad's truck, and the only cure we could come up with was greasing it more often - like every second oil change.

We tried synthetic lube, too. It lasted longer, but...

Good luck with it - don't leave it so long before you check it again, 'K?

 

[Unit453]

We'll see how long this lube can last...

 

[shortcircut65]

maybe thats why i have a vibration at highway speeds? i was thinking about doing this, but couldnt find the time. how long did it take you guys to do it Nick?

 

[Unit453]

Maybe 30 minutes to drop the shaft, lube it and bolt it back up. My truck's accumulated a metric shit ton of rust up north so it wasnt the easiest job. The U joints were pretty much rusted to the housing. With help of a large flat head, we got them loose.

If you have an hour, you can do this yourself. There was two of us so it obviously went faster.

 

[shortcircut65]

thanks, just might do it today. my shaft is nothing but rust, so i know what your talking about

 

[CtChevy427]

maybe thats why i have a vibration at highway speeds?

Ken, when you put the drive shaft back in turn it 180* and see if the vibration goes away.

my shaft is nothing but rust, so i know what your talking about

Sounds like you have a problem there Ken. ):h

 

[CtChevy427]

We then inspected the yoke to see why this problem is happening to so many trucks.

For one, it was bone dry. Not a drop on it, nothing, nada. It was piping hot. Hot as in we couldnt touch it for more than a few seconds. I have no idea if this is normal or not.

Nick, did you check the level of transfer case fluid?

 

[shortcircut65]

Ken, when you put the drive shaft back in turn it 180* and see if the vibration goes away.

judging by Nicks pictures, i cant do that because of a missing spline? or are there two missing splines on opposite ends?


Sounds like you have a problem there Ken. ):h

.....

 

[CtChevy427]

Jack up the back of the truck and turn the yoke on the differential 180*. I have read sometimes this gets rid of the vibration.

 

[Sparky8370]

thanks, just might do it today. my shaft is nothing but rust, so i know what your talking about

So, you're married huh?

 

[shortcircut65]

not yet Jay. i am about to tackle it in a few minutes, will let you know what comes of it.

 

[btfarm]

So... back on topic!):h
I've had this nasty shake in my truck for about 10-15k. I thought it was just from the bad RF hub but that only partly solved it. I figured something in the front end and couldn't find it while on jack stands last week. Took it to my alignment guy last Friday and we checked it out on the rack after he test drove it. He thinks it's a u-joint because the front end is tight. I haven't pulled the shaft (driveshaft ) yet but plan to tomorrow night. We'll see. Good idea about turning the differential yoke 180*.
BTW, I checked for heat at both u-joints when it went on the rack and felt none.

 

[Unit453]

Nick, did you check the level of transfer case fluid?

Grady checked it while I sanded down some of the rust off the yoke and he said it was fine.

I also hear that there's a TSB for this yoke. I guess there's a new one out thats a different material or something. I'll have to look into that.

 

[stacks04]

nick the bulletin only applies for 04 and older stuff. it should be in your already. for what its worth, this is uncommon, if the new lube doesnt help look into it further. years back we used to use the "super balls" bouncey balls in the yoke to put some tension on the yoke. worked like a charm.

 

[Unit453]

I think for as hot as that bastard was when we pulled it off, it would've cooked anything inside there.

 

[CtChevy427]

Nick, was the transfer case hot as well or just the yoke? What back there could generate that heat. I would find it hard to believe the contact with the seal could get it that hot.

I'm gonna roll under mine tonight when I get home and see how hot things are after a 40 minute commute consisting of all highway driving.

 

[Unit453]

The transfer case was hot but the shaft/yoke was piping hot. It was too hot to touch and it was starting to blue from the heat. Like I said, I have no idea if this is normal or not but its evidently cooking up the grease thats on there.

 

[saratoga]

The yoke was really hot... much hotter than the transfer case or the tailshaft.

I don't know jack about the xfer case or what the driveshaft rides inside, but from my unprofessional position, it looked like whatever was causing the yoke to heat up was doing it from the annular space around the slip yoke based on the discolored pattern on it. I don't know if there's a roller bearing or just a dust seal around the slip yoke, but it definitely looks like something is/was rubbing the OD of the yoke. Nick rubbed some grease around the OD before putting it back in.

 

[Unit453]

I wonder if we should've put some on the outside of it before we put it back in.