How To Grease The Slip Yoke

RayGMC · April 24, 2010

crewdawg1981--Is the sound predictable? If not, it could be the heat shield.

I've read of people stating a similar issue but it was related to the heat shield just above a section of their exhaust. What was happening was the heat from the exhaust caused the metal to expand and subsequently pop out of shape. When it did that they heard a bang like yours. Try researching this subject on www.z71tahoe-suburban.com. I think that is where I read about it.

Wingnut · April 26, 2010

Just a follow up on the slip yoke problem...i purchased my 07 sierra CC with 24,000 miles on it and within a couple thousand miles had noticed the bump. My first thought was HOLY SH*T i bought a lemon! After taking it to the dealer, they told me about the slip yoke problem and lubed it for me, under warranty of course. Now 10,000 miles later the bump is back. I took it to the dealer again and they said there was TSB that stated they had to replace the slip yoke with a new one of a different material (I'm assuming nickel plated based on what I've read here) if it came back a second time. The paperwork read as follows:

"Customer reports a loud "klunk" noise in the driveline after sitting at a stop and then accelerating away / see history. Found "klunk" on decel/takeoff. Found slack in slip yoke previously lubed on Ro#******. Replace slip yoke per bulletin 09-04-17-002 and lubricate. Test drove to verify repair."

Truck is back to smooth for now....so we'll see how long it lasts. Just thought this might help some people who said they have had this problem multiple times. Don't let the dealer push you around!

It comes back. I've had to grease the one on my truck twice in two years. Takes 20 minutes if I'm taking my time and taking beer breaks.

gsfr659 · April 26, 2010

Awesome... At least its an easy fix, good excuse to drink beer i guess! Wingnut, what kind of grease are you using?

Wingnut · April 26, 2010

Some stuff I bought at Autozone for about $4.

gsfr659 · April 29, 2010

Seems lke a lot of guys on here are having good luck with marine grease or even Lucas Red and Tacky grease. Just to let you know wingnut

Wingnut · April 30, 2010

Pretty sure I used Mobile 1 Synthetic GP grease (got a couple of tubs on the shelf).

Or I may have used that white lithium stuff out of the tube (got a couple of tubes on the shelf).

One or the other....But whichever one it was...It worked.

emejay · May 31, 2010

No need for a "special" grease... and no, it won't contaminate your trans fluid.

Read this: http://www.truckmodcentral.com/forums/showthread.php?t=2504

Thanks for this link to a great post. My 07 Sierra started to clunk about 60K miles, and it now has 97K and getting worse and driving me nuts. I would normally not attempt this job as I have no knowledge of driveshats, but the article you wrote made it easy! I was surprised how the driveshaft didn't weigh 200 pounds.

I bought some marine trtailer bearing grease at the local boat store....it was dark red, thick, and smelled like sulphur. I used about 2 heaping teaspoons of the stuff. The results were immediate. While I was down there getting dirty, I sprayed the leaf springs and shackles with a teflon spray, and got those babies so they don't squeek.

Next job: try to figure out if it's possible for me to change all 8 spark plugs and wires as this truck is approaching 100K miles.

Thanks for all the information!

DFWSierra · June 3, 2010

I just got under my truck to see how easy or hard it would be to take the the drive shaft off. I have the occasional clunk as well. Two of the bolts came out no problem. The other too seemed like they were too long and would hit the end of the drive shaft before coming all the way out.

I didn't really try and mess with it that much since I haven't bought the marine grade grease yet. Is there a trick to getting some of the bolts out? Do I need to rotate the shaft some to get the other bolts out easier? I will hopefully try this weekend when I have the correct grease.

spikesputnik · June 3, 2010

Well this thread got me inspired, so I did my yoke today and found it to be too easy! Should have done it a couple of months ago... hopfully it is/was the cause of the "bump" at a stop light....

A few of observations. The bolts for me came out surprisingly easy- not much torque required, though "dislodging" the universal just a bit with the bolts unthreaded half way made their removal easier as they back out into the shaft before competely unthreaded. Second, the yoke itself looks to be designed to go on only one way as there is one "double valley", but there is not coresponding "double wide ridge" on the trany side of things??? I marked it anyways and reinstalled the same. Mine had some grease on it- enough that I would think that it would not bind, but it was kinda milky looking- kinda like lubriplate, or water contaminated? Oh, and some tranny fluid did drip out of the weep hole in the seal- maybe 2-3cc only. But I did have the front end up on ramps just to make it easier to move around underneath. Also, holy cow, that aluminum shaft with yokes/universal probably doesn't weigh 20-25#!! Lastly, the seal and shaft themselves were what I would call squeaky clean, so on reassembly I left just a touch of grease there too. And on reassembly blue locktighted the bolts just so I'd feel better

Test drive later, hopefully won't leave the driveshaft on the side of the freeway

x-tactical · June 4, 2010

I don't understand why grease is needed. On a 2 wheel drive the trans oil should get into the inside of the yoke and lube it. And the same for a 4 wheel drive the transfer oil should get inside the yoke to lube it. Chevrolets have had a yoke going in the transmission since 1955 and I never have heard of this before. I don't see why they do now.

Thurman · June 6, 2010

The following information is gathered from me working part-time at an auto parts store, talking to the mechanics who come into the store, delivering to the shops, and asking about this very topic. The overwhelming majority of mechanics who have worked on this problem state that using "Marine Grade Grease" ( green in color, about 2 oz., and which goes in the foot of outboard motors) is the only way to solve this problem. Cleaning the inside of the splines of the slip yoke is essential also. As far as tranny fluid leaking from the rear of a 4L60E tranny, I'm told that there are two (2) seals in this tranny. One is for the slip yoke to go into and it's purpose is to keep dirt out of the tranny. There is another seal further into the tailshaft of the tranny which is supposed to keep tranny fluid from leaking out even if the tranny is tilted down in back. So they say. Sir, I'm sorry but my training taught me that "Lubriplate" contains some amounts of ground up aluminum particles, this the color of the material. It is a great lubricant for what it is intended to be used on. We used it on slideways where metal met metal, but not on sensitive parts such as hydraulic systems nor automatic transmissions. Just my 2¢ worth, David

emejay · June 7, 2010

I just got under my truck to see how easy or hard it would be to take the the drive shaft off. I have the occasional clunk as well. Two of the bolts came out no problem. The other too seemed like they were too long and would hit the end of the drive shaft before coming all the way out.

I didn't really try and mess with it that much since I haven't bought the marine grade grease yet. Is there a trick to getting some of the bolts out? Do I need to rotate the shaft some to get the other bolts out easier? I will hopefully try this weekend when I have the correct grease.

I encountered the same situation. Just move the driveshaft forward into the transmission to get clearance to remove the two bolts. I used a rubber mallet to loosen things up to get her to move .

Zembonez · June 7, 2010

I don't understand why grease is needed. On a 2 wheel drive the trans oil should get into the inside of the yoke and lube it. And the same for a 4 wheel drive the transfer oil should get inside the yoke to lube it. Chevrolets have had a yoke going in the transmission since 1955 and I never have heard of this before. I don't see why they do now.

There is no oil circulating at the tail shaft where the slip yoke is located. It's a dry connection. The grease inside the yoke has no contact with the transmission oil.

Zembonez · June 7, 2010

I don't understand why grease is needed. On a 2 wheel drive the trans oil should get into the inside of the yoke and lube it. And the same for a 4 wheel drive the transfer oil should get inside the yoke to lube it. Chevrolets have had a yoke going in the transmission since 1955 and I never have heard of this before. I don't see why they do now.

There is no oil circulating at the tail shaft where the slip yoke is located. It's a dry connection. The grease inside the yoke has no contact with the transmission oil.

c03camson · June 11, 2010

Is this slip yoke clunk referring to the 2-3 clunk? Thats prettymuch the only time my truck makes that noise. On the downshift from 2-1 it makes a tiny noise but nothing big. But I did lube the slip yoke the other day with some marine grade grease and the 2-3 clunk is still there so Im thinking that I didnt put enough grease in there. Maybe Ill take it back off and clean it better and put more grease.

Also, do they sell aftermarket nickel plated yokes or do I have to go to the dealer? Thanks