Clunking Noise =(

[blueZ71]

Hey there. Maybe I'm just not used to all the clunking and rattling of a truck but I'm sure this one should not be happening. In my 2000 silverado I hear a loud very audible clunking noise (passengers notice it as well) which sounds like it's coming from the rear of the truck whenever I accelerate hard from a dead stop. It sounds like something in the drivetrain is slipping and then catches suddenly. I posses nominal mechanical knowledge but I'm thinking maybe the u-joints need to be replaced? Anyone else every experience anything similar or willing to shed some light on the situation? Thanks a bunch!

[retired2001]

Is it a "single" clunk just on taking off? If so it may well be slack in the drive line. There have been "clunks" coming from the shaft coming from the splines in the transmissioin. Also, might look at all suspension bolts. At least a place to start looking. Good luck!

[vncj96]

Most likely u-joints or rear end, crawl underneath and try and twist the driveshaft, I bet you have alot of play in it

[blueZ71]

Yea it's a single clunk. What would cause play in the driveshaft?

[vncj96]

The u joints are shot or if your rear end has some problems it will start to allow slack, the rear end thing can be a bunch of different things, but if there is too much play while its in park then its one of the two. So just try and turn it and see how much you get

[mrfixdit]

Do you have a posi rear?

[blueZ71]

Do you have a posi rear?


Not sure. It's the z71 so I would think so.

I'll check it tonight after school and report back.

[cascott325]

i have the exact same thing in my truck. one single clunk and its over till i stop again and then take off... just on the take off, not on the stop. i have replaced the rear end with a used one, and the u joints, so im sure its neither of those. i had the same thing with the old rear end and u joints, so i dont know. wasnt sure how to explain it, so i didnt post about it, but you did a good enough job for the both of us. i dont know what it could be.

[bartmk]

I've done all kinds of research on this subject myself. I have a '01 Silverado Z71 with the same thing going on. From the other forums I've read it's the piece that slips into the transmission and connects the trans with the driveshaft. My driveshaft has no play in it but I get the clunk also. Supposedly it's that piece (the tube shaped one with the spline on the inside) that needs to be replaced. From what I've read GM offers a replacement one that is of better quality. The guys on the other forums seem to get the same message from the dealer... they tell them that it's a normal noise. Not sure I believe that but I'm just going to let mine be for now.

[cascott325]

I've done all kinds of research on this subject myself. I have a '01 Silverado Z71 with the same thing going on. From the other forums I've read it's the piece that slips into the transmission and connects the trans with the driveshaft. My driveshaft has no play in it but I get the clunk also. Supposedly it's that piece (the tube shaped one with the spline on the inside) that needs to be replaced. From what I've read GM offers a replacement one that is of better quality. The guys on the other forums seem to get the same message from the dealer... they tell them that it's a normal noise. Not sure I believe that but I'm just going to let mine be for now.


i seem to have a normal driving and performing vehicle, so except for the noise, i think every thing i ok and wont take it any where as well

[blueZ71]

I've noticed an extreme drop in performance recently. I drive my truck like a bat out of hell and lately she just hasn't been pulling so hard. I've only been driving it a few months but the clunking seems to be more and more noticable. I just quit my job so I don't see myself getting it fixed soon but if I do I'll post up on what it was.

[05azsilver]

I would recommend to postpone driving "like a bat out of hell" until you get the problem resolved.

[bucknasty]

I think it is after 98' in all chevy's that have a stock posi locker in the rear diff. straight off the lot. but if you dont think that it is your locker kicken in on acceleration. Then on the splines that go into the back of the transfer case has a thin film of grease that slowly wears off. Just go to the local auto zone or who ever you like and get a thicker bearing grease for like ten bucks compared to the 50+ dollars you would pay for the gm dealer to put on and give the grease some fancy name. I've heard of that litlle annoying clunk that nobody can figure out but that should fix it.

[chevyrulz]

it is the slip yoke. you can either re-grease it or replace with the updated nickel plated one. both are temporary solutions. it's a GM design flaw. it's not going to hurt anything. it just annoys you if your a perfectionist like me. my tahoe does it real bad, but my '04 silverado doesn't...yet...

the slip yoke should be re-greased every 12-15,000 miles IIRC (if i remember correctly), just like the ball joints should be regreased every oil change (3-5,000 miles)


ETA(edited to add):

Jamie

1997 Tahoe 2 door 4x4 LS
2004 Silverado 4.8L v8 5spd single cab short bed =)



edit2:

the slip yoke is simply the most common cause of the problem described. a driveline "clunk" can be caused by a multitude of things. it could be inside the rear-end itself, perhaps a pinion bearing. the ring or pinion teeth could be damaged. the ujoints could be worn out (doubtful b/c the symptoms are different). a shock mount or body mount could be missing, loose, or damaged. could be a wheel bearing or an axle issue. i mean the list is really endless. take it to a reputable mechanic shop for diagnosis. then go to 2 more and if they all tell you it's fine, drive it till it breaks...

by the way, every 4x4 GM truck or SUV i've ever driven did this to some extent. it's a design flaw...




edit3:

here's the tsb (tech service bulletin):

Clunk, Bump or Squawk when Vehicle Comes to Complete Stop or Accelerating from Complete Stop or Accelerating from Complete Stop (Replace Rear Drive Shaft Nickel-Plated Slip Yoke) #01-04-17-004B - (Jan 5, 2005)Clunk, Bump or Squawk when Vehicle Comes to Complete Stop or Accelerating from Complete Stop (Replace Rear Drive Shaft Nickel-Plated Slip Yoke)
1999-2000 Cadillac Escalade (Old Style)

2002-2004 Cadillac Escalade, Escalade EXT

2003-2004 Cadillac Escalade ESV

1996-1999 Chevrolet 1500 Series Extended Cab Short Box Pickup (Old Style)

1996-1999 Chevrolet 1500 Series Regular Cab Pickup and Utility Models (Old Style)

1999-2002 Chevrolet Silverado Extended Cab Short Box (New Style)

1999-2004 Chevrolet Silverado 1500 Series Regular Cab (New Style)

2000-2004 Chevrolet 1500 Series Avalanche, Suburban and Tahoe

2001-2004 Chevrolet Silverado 2500/3500 Series Regular Cab with Long Bed or Extended Cab (New Style)

2001-2004 Chevrolet Silverado 2500 Series Crew Cab, Short Box (New Style)

1996-1999 GMC 1500 Series Extended Cab Short Box Pickup (Old Style)

1996-1999 GMC 1500 Series Regular Cab Pickup and Utility Models (Old Style)

1999-2002 GMC Sierra Extended Cab Short Box (New Style)

1999-2004 GMC Sierra 1500 Series Regular Cab (New Style)

2000-2004 GMC 1500 Series Yukon, Yukon XL

2001-2004 GMC Sierra 2500/3500 Series Regular Cab with Long Bed or Extended Cab (New Style)

2001-2004 GMC Sierra 2500 Series Crew Cab, Short Box (New Style)

2003-2005 HUMMER H2

with Four Wheel Drive (4WD) or All Wheel Drive (AWD) and One-Piece Propeller Shaft ONLY

This bulletin is being revised to add Cadillac Escalade (Old Style) and HUMMER H2 to the Models section. Please discard Corporate Bulletin Number 01-04-17-004A (Section 04 -- Driveline/Axle).

Condition
Some customers may comment on a clunk, bump or squawk noise when the vehicle comes to a stop or when accelerating from a complete stop.

Cause
A slip/stick condition between the transfer case output shaft and the driveshaft slip yoke may cause this condition.


Part Number
Description
Usage

12477702
Yoke Asm., Prop Shf Slip (with u-joint) , Nickel Plated
4WD/AWD 1500 Series Ext Cab Short Box Pickups (New Style and Old Style)

12477704
Yoke Asm., Prop Shf Slip (with u-joint) , Nickel Plated
4WD/AWD 2500 Series Ext Cab Short Box Pickups (New Style)

12479383
Yoke Asm., Prop Shf Slip (without u-joint) , Nickel Plated

Must Be Ordered With U-Joint Kit P/N 12479126
4WD/AWD 1500 Series Silverado, Sierra Regular Cab Pickups (New Style)

4WD/AWD 1500 Series Suburban, Avalanche, Yukon XL, Escalade EXT, Escalade ESV with AWD (New Style)

K1500 Series Regular Cab Pickup, Tahoe, Suburban, Escalade (Old Style)

12479384
Yoke Asm., Prop Shf Slip, (without u-joint) , Nickel Plated

Must Be Ordered With U-Joint Kit P/N 12479126
4WD/AWD 1500 Series Tahoe, Yukon, Escalade w/ 4WD or AWD (New Style)

12479385
Yoke Asm., Prop Shf Slip (without u-joint) , Nickel Plated

Must Be Ordered With U-Joint Kit P/N 12471510
4WD/AWD 2500HD/3500 Series Silverado and Sierra Regular Cab, Long Bed Pickups with 6.0L (RPO LQ4) Engine (New Style)

89058876
Yoke Asm., Prop Shf Slip (with u-joint) , Nickel Plated
4WD/AWD 2500HD Series Silverado and Sierra Crew Cab, Short Bed Pickups with 5-Speed Allison Transmission (RPO M74) (New Style)

4WD 2500HD/3500 Series Silverado and Sierra Extended Cab Long Bed Pickups with 5-Speed Allison Transmission (RPO M74) (New Style)

4WD 2500HD/3500 Series Silverado and Sierra Regular Cab, Long Bed Pickups with 5-Speed Allison Transmission (RPO M74 build date before 2/2004) (New Style)

4WD/AWD 2500HD Series Silverado and Sierra Extended Cab, Short Bed Pickups with 5-Speed Allison Transmission (RPO M74 build date before 2/2004) (New Style)

89058878
Yoke Asm., Prop Shf Slip (with u-joint) , Nickel Plated
4WD/AWD 2500HD/3500 Series Silverado and Sierra Extended Cab Pickups with 6.0L (RPO LQ4) Engine (New Style)

4WD 2500HD Series Silverado and Sierra Crew Cab, Short Bed Pickups with 6.0L (RPO LQ4) Engine (New Style)

89058880
Yoke Asm., Prop Shf Slip (with u-joint) , Nickel Plated
4WD/AWD 2500HD/3500 Series Silverado and Sierra Regular Cab, Long Bed Pickups with 5-Speed Allison Transmission (RPO M74 build date after 2/2004) or 6-Speed Manual Transmission (RPO ML6) (New Style)

4WD 2500HD Series Silverado and Sierra Extended Cab, Short Bed Pickups with 5-Speed Allison Transmission (RPO M74 build date after 2/2004) or 6-Speed Manual Transmission (RPO ML6) (New Style)

12479126
U Joint Kit
4WD/AWD 1500 Series Silverado, Sierra Regular Cab Pickups (New Style)

4WD 1500 Series Suburban, Avalanche, Yukon XL) (Escalade EXT, Escalade ESV with AWD (New Style)

4WD 1500 Regular Cab Pickup, Tahoe, Suburban, Escalade (Old Style)

Tahoe, Yukon, Escalade w/ 4WD or AWD (New Style)

12471510
U Joint Kit
4WD/AWD 2500HD/3500 Series Silverado and Sierra Regular Cab, Long Bed Pickups with 6.0L (RPO LQ4) Engine (New Style)

88964470
Yoke Asm., Prop Sft Slip (without U joint) Nickel Plated

Must be ordered with U joint kit P/N 88964507
HUMMER H2

88964507
U-Joint
HUMMER H2

[bry2500]

Got the same noise on hard takeoffs. not at normal take offs. This post really opens up my eyes to where to start first. Need an oil change so I will grease the slip yoke good when i'm under there next week. I'll report back with the results.

[vin_bom]

I have the same issue with my '08. I found a tech bulletin on this issue (I work for GM).
#PIP4020G: Groan, Clunk or Bump Noise from Launch or at Stop.
They recommend dealers to lube the driveshaft slip yoke splines. This is a temporary repair and still under investigation.

[Land Shark]

Two days ago my girl was driving my 03' tahoe and she never told me that she heard a loud clunk noise in the rear end. So she calls me a day later from the side of the road saying the truck won't move. i had to pay to get it towed and moved it to two different shops for estimates. Final result is, ring and pinion destroyed along with the spider gears.....oh yeah the replacement jasper rearend is gonna run me about $2000.00 installed.....hope yours doesn't turn out to be this bad.

[cascott325]

dude... unless you just want a brand new rear end, call some junk yards and pull apart lots. you may have to travel a little to get to it, but you can find a good one for alot less. mine went out, and it was 850 for a good used replacement installed and out the door

[blueZ71]

Two days ago my girl was driving my 03' tahoe and she never told me that she heard a loud clunk noise in the rear end. So she calls me a day later from the side of the road saying the truck won't move. i had to pay to get it towed and moved it to two different shops for estimates. Final result is, ring and pinion destroyed along with the spider gears.....oh yeah the replacement jasper rearend is gonna run me about $2000.00 installed.....hope yours doesn't turn out to be this bad.

That's scary. I feel for you man.

If I get some time over the 3 day weekend I'll grease the slip yoke as well. Anyone got a link to an online repair manual for a 2000 silverado? And while we're on the subject, does anyone subscribe to alldata? I remember using it at school and it was helpful.

[cascott325]

That's scary. I feel for you man.

If I get some time over the 3 day weekend I'll grease the slip yoke as well. Anyone got a link to an online repair manual for a 2000 silverado? And while we're on the subject, does anyone subscribe to alldata? I remember using it at school and it was helpful.
there is a person on here who is selling dvd manuals for $22. ill try to find the link and post it. in the mean time, if anyone else can find it, or if that person catches this thread, please let us know. thanks


i think it may be trhrought the user silveradojc. search his posts and threads

[kinglt1]

it is the slip yoke. you can either re-grease it or replace with the updated nickel plated one. both are temporary solutions. it's a GM design flaw. it's not going to hurt anything. it just annoys you if your a perfectionist like me. my tahoe does it real bad, but my '04 silverado doesn't...yet...

the slip yoke should be re-greased every 12-15,000 miles IIRC (if i remember correctly), just like the ball joints should be regreased every oil change (3-5,000 miles)


ETA(edited to add):

Jamie

1997 Tahoe 2 door 4x4 LS
2004 Silverado 4.8L v8 5spd single cab short bed =)



edit2:

the slip yoke is simply the most common cause of the problem described. a driveline "clunk" can be caused by a multitude of things. it could be inside the rear-end itself, perhaps a pinion bearing. the ring or pinion teeth could be damaged. the ujoints could be worn out (doubtful b/c the symptoms are different). a shock mount or body mount could be missing, loose, or damaged. could be a wheel bearing or an axle issue. i mean the list is really endless. take it to a reputable mechanic shop for diagnosis. then go to 2 more and if they all tell you it's fine, drive it till it breaks...

by the way, every 4x4 GM truck or SUV i've ever driven did this to some extent. it's a design flaw...
Listen to this guy, he is 100% correct.

[kinglt1]

it is the slip yoke. you can either re-grease it or replace with the updated nickel plated one. both are temporary solutions. it's a GM design flaw. it's not going to hurt anything. it just annoys you if your a perfectionist like me. my tahoe does it real bad, but my '04 silverado doesn't...yet...

the slip yoke should be re-greased every 12-15,000 miles IIRC (if i remember correctly), just like the ball joints should be regreased every oil change (3-5,000 miles)


ETA(edited to add):

Jamie

1997 Tahoe 2 door 4x4 LS
2004 Silverado 4.8L v8 5spd single cab short bed =)



edit2:

the slip yoke is simply the most common cause of the problem described. a driveline "clunk" can be caused by a multitude of things. it could be inside the rear-end itself, perhaps a pinion bearing. the ring or pinion teeth could be damaged. the ujoints could be worn out (doubtful b/c the symptoms are different). a shock mount or body mount could be missing, loose, or damaged. could be a wheel bearing or an axle issue. i mean the list is really endless. take it to a reputable mechanic shop for diagnosis. then go to 2 more and if they all tell you it's fine, drive it till it breaks...

by the way, every 4x4 GM truck or SUV i've ever driven did this to some extent. it's a design flaw...
Listen to this guy, he is 100% correct.:great:

[route66paul]

Is the slip yoke the retainer for the 2 piece driveshaft? these go out on the trucks that have them, you hear a clunk when changing into gear and a vibration in the floor. crawl under and try to move the driveshaft from side to side. This mount seems to be the same on my old 1969 longhorn and my 91 sub.

[ukrkoz]

fellas, KISS.
1. clunk is caused by slip yoke. it rusts as it is made out of inferior materials and binds to the output shaft.
GMC is a bunch of cheapskates, so they tell dealers to "exercise" yoke with GM miracle grease, which lube with PTFA. After several exercises, if you are still under warranty and pissed enough to raise hell, they will replace yoke with nickel plated one. Greasing works only for few mths - I know 1st hand - and problem comes back. So, if you can replace yoke and have good source for one - do it. Dealer charges $470 for this, I think.

2. as of it being completely harmless - I have 2nd thought on this. Yoke binds to the output shaft. This causes additional stress on the shaft every time you take off, esp - if you rip it or it's loaded. My output shaft wobbles in the tail section like craizy, and I am most positive binding yoke had some to do with this.

[blueZ71]

anyone know the part number for a 2000 silverado ext cab replacement nickel plated yoke? thanks

[chevyrulz]

if you guys are mechanically inclined, i've heard you can just sand/grind the stock one a bit smoother before you regrease to keep things from clunking for longer. the slip yoke sticks and causes the clunk so no matter what you do it's going to come back. the only way to prevent it is to remember you're driving a truck, not a corvette. be easy when u get into the throttle, and your truck won't do this. once you've taken up the slack in the drive line you can feel free to hammer the throttle, but if u floor it off the line it's going to clunk worse & worse till it goes bam and your stranded.

the nickel plated yoke is probably around $300 & average install charge is going to be 1 hour (~$75), so the sanding method is much cheaper.


edit:

i posted the TSB in my original post, it should tell you the symptoms and the part# to fix for your model.

most non-corporate small repair shops have an alldata subscription. stop by a few and see if u can't get one to hook u up with a printout. i might be able to get it from my buddy's transmission shop if you give me the make/model/year & part of interest.

[kinglt1]

Is the slip yoke the retainer for the 2 piece driveshaft? these go out on the trucks that have them, you hear a clunk when changing into gear and a vibration in the floor. crawl under and try to move the driveshaft from side to side. This mount seems to be the same on my old 1969 longhorn and my 91 sub.

I think you are refering to the carrier bearing.

[blueZ71]

i might be able to get it from my buddy's transmission shop if you give me the make/model/year & part of interest.
It's a 2000 Chevrolet Silverado Extended Cab and I'm interested in the nickel plated slip yoke. Thanks!

[cascott325]

It's a 2000 Chevrolet Silverado Extended Cab and I'm interested in the nickel plated slip yoke. Thanks!

i second that motion. all my details are in my sig. thank you

[chevyrulz]

It's a 2000 Chevrolet Silverado Extended Cab and I'm interested in the nickel plated slip yoke. Thanks!
if u read my post on the 2nd page it tells you what part number for what model year and options


GM PART # 12477702
GM LIST: $271.93

that only works for 4x4 extended cab short bed 1500 series silverado & sierra pickups

for 2500, shortbed, suburban, avalanche, and others u need a different u joint kit or something it says

[cascott325]

thanks, i guess i am blind. lol

how hard is it to replace this part? can i do it on my own, or should i take it to a mechanic. i have friends who are a little more mechanically inclined than I, so im thinkin it shouldnt be too hard to figure out.

[blueZ71]

I guess my problem wasn't the slip yoke.. I got it up on jacks the other day and had a good look at her.. welded up some exhaust leaks while I was at it.. anyways I noticed the rear output seal on the tranny was leaking so I just brought it in to the transmission shop under warranty and told them it was their problem and to deal with it. So far they've replaced the torque converter, that rear seal, and greased the slip-yoke. She still clunks :gasp:. U joints are fine, slip yoke greased, it's not the tranny.. what's next?

[bucknasty]

put a pipe bomb in the gas tank im pretty sure it wont clunk anymore.

[bucknasty]

im interested though where you said that the seal was leaking there might be some internal damage like some possible bad bearings or worn gears that would cause the clunk noise and the seal to go out. did the shop go into the tranny at all?

[blueZ71]

The driveline actually exits out of the transfercase so the transmission shop wouldn't mess with that under warranty. I got them to replace the seal for a few bucks but other than that no they didn't get into the transfercase. They narrowed the problem down to my driveline, which is apparently coming apart from the inside out.

[dangerous dave]

Correction (http://gsi.xw.gm.com/si/showDoc.do?docSyskey=1580377&from=bcpi#ss4-1580377)


Replace the rear drive shaft slip yoke with a new nickel-plated slip yoke. See the parts table below
Follow the service procedure below.
1. Raise the vehicle on a hoist. Refer to Lifting and Jacking the Vehicle in General Information (SI Document ID #349918).
2. Reference mark the propeller shaft to the pinion flange connection.
Important: Do not pound on the propeller shaft yoke ears. Never pry or place any tool between a yoke and a universal joint.
3. Remove the bolts and the yoke retainers from the pinion flange.
4. Slide the propeller shaft forward and out of the rear pinion flange.
5. Lower the rear of the propeller shaft and pull the driveshaft out of the transfer case.
Notice: Never clamp propeller shaft tubing in a vise. Clamping could dent or deform the tube causing an imbalance or unsafe condition. Always clamp on one of the yokes and support the shaft horizontally. Avoid damaging the slip yoke sealing surface. Nicks may damage the bushing or cut the lip seal.
6. Support the propeller shaft in a line horizontal with the table of a press.
Important: Remove the front slip yoke and the universal joint together. The new nickel-plated slip yoke comes with a new universal joint.
7. Disassemble the snap rings by pinching the ends together with a pair of pliers.
8. If the ring does not readily snap out of the groove in the yoke, tap the end of the cup lightly in order to relieve the pressure from the ring.
9. Place the universal joint so that the lower ear of the yoke is supported on a 30 mm (1-1/8 in) hex head socket or a 27 mm (1-1/16 in) socket.
10. Place the J 9522-3 on the open horizontal bearing cups. Press the lower bearing cup out of the yoke ear.
11. If you do not completely remove the bearing cup, lift the cross and insert the J 9522-5 between the seal and the bearing cup you are removing. Continue pressing the bearing cup out of the yoke.
12. Rotate the propeller shaft . Press the opposite bearing cup out of the drive shaft yoke.
13. Remove the old slip yoke and universal joint.
14. Inspect the retaining ring grooves for dirt, corrosion, or pieces of the old ring.
15. Inspect the bearing cup bores for burrs or imperfections.
16. Clean the retaining ring grooves. Corrosion, dirt, rust, or pieces of the old retaining ring may prevent the bearing cups from pressing into place or prevent the bearing retainers from properly seating.
17. Install the new nickel-plated slip yoke and universal joint. See parts table below for parts information.
18. Remove the bearing cups from the universal joint.
19. Assemble one bearing cup part way into one side of the yoke. Turn the yoke ear toward the bottom.
20. Assemble the cross into the yoke so that the trunnion seats freely into the bearing cup.
21. With the trunnion seated in the bearing cup, press the bearing cup into the yoke until the bearing cup is flush with the yoke ear.
22. Install the opposite bearing cup part way into the yoke ear.
23. Ensure that the trunnions start straight and true into both bearing cups.
24. Press the opposite bearing cup into the yoke ear while working the cross all the time in order to inspect for free unbinding movement of the trunnions in the bearing cups.
Important: If there seems to be a hang up or binding, stop pressing. Inspect the needle bearings for misalignment in the bearing cup
25. Press the bearing cup into the yoke until the bearing cup retainer groove is visible over the top of the bearing cup.
26. Assemble the bearing retainer in the retainer groove.
27. Continue pressing until both retainers can be snapped into place.
28. If the retainer is difficult to seat, the yoke can be sprung slightly with a firm blow from a soft-faced dead blow hammer.
29. It may be necessary to lubricate the snap ring with a slight amount of chassis grease so that the snap ring seats in the bearing cup groove.
30. Install the slip yoke onto the output shaft in the transfer case.
31. Align the reference marks on the pinion flange and the propeller shaft.
32. Install the yoke retainers and bolts.
Tighten
Tighten the yoke retainer bolts to 25 N·m (19 lb ft).
33. Lower the vehicle.
these are the instructions how to fix it...all hail bob?

[chevyrulz]

The driveline actually exits out of the transfercase so the transmission shop wouldn't mess with that under warranty. I got them to replace the seal for a few bucks but other than that no they didn't get into the transfercase. They narrowed the problem down to my driveline, which is apparently coming apart from the inside out.

the part i'm talking about is mated to the transfer case, i think you should probably seek a professional mechanic...

if i had to bet, you need to change the fluid in your transfer case and replace/regrease the slip yoke. unless your transfer case needs a rebuild...


edit:


5. Lower the rear of the propeller shaft and pull the driveshaft out of the transfer case.

[drs022bow]

I had the same problem with my 2000 z71 from new till now. When new they had to change my rear end fluid twice. It quit for about 50000 miles then started again. I changed the fluid and fixed it myself the next time. It now has 155000 miles and it is starting again. Will drain and fill rear end again and should fix it.

[sledtrash]

So I read these post this morning and I have the same problem a clunking when taking off from a dead stop. So I pulled my driveline and greased it up and put it back together. No more noise. But I do believe that this is just a bandaid for the problem. When I pulled it apart I didn't think greasing it would work. it was like the yoke was dry or anything it had oil on it and so I thought problem must be somewheres else. But it isn't making noise so it must be.

And correct me if I'm wrong in my 94 1500 ext cab short bed there was ATF from the transfercase at the rear seal, is this not so with the newer models? If there is constant ATF around the yoke it shouldn't need grease. That is the purpose of having the seal to keep the dust and grime out of the oil in the transfer case...

Yes GM could have a problem with the yoke but could the underlying problem be with the new auto 4x4 transfer case?

My current truck is a 1999 1500 new body style 5.3 with a 4L60e transmission

[tks20]

I bought my truck new and the clunking started around 10,000 miles. Replaced rearend, U-joints, rebiult tranny. Ifinally figured out it was the play in the yoke. My solution = dropped the drive shaft, compressed a ping-pong ball with ample grease into the slplines and pushed to the bottom. Takes about 20 minutes and lasts about a year.

[BenEllis]

I have an 02 Z71 EXT, had the same problems. My issue ended up being my shackles ( leaf springs ). They were old and rusted and were actually popping on takeoff when the truck would squat. Dealer said to lube them up with WD-40 every now and then, and it has worked, no more clunking.

[thrasher]

If it's a 4X4 and has the torsion bar front suspension, check the torsion bar cross member mounts. They mount the torsion bar cross member to the frame, and have rubber bushings. I replaced mine last year after hearing a clunking sound taking off from a dead stop. They're pretty easy to replace. All you have to do is cut the rivets with a high speed grinder & pop them out with a hammer & drift, then bolt in the new ones. Use grade 8 bolts with flat & lock washers and Ny-lock nuts. takes about 1 hour to do.

[Z_10002003]

The noise is coming from the slip yolk, the only way to get rid of it, is to replace it with the nickle plated one that gm uses to fix the clunk problem. This is a super common, often miss diagnosed problem. I'm not sure it the part is available to the aftermarket, but you should be able to go to any gm dealer parts dept. and order one, they probably have it on the shelf.

[buffalojoem]

First, check the vehicle for loose objects rolling around-anywhere in or out of the vehicle.
Next, if the U-joints are OK you may want to change the rear-end oil.
It probably has an Anerican axle "G-80" option for trailering which has clutches.
Bring your VIN number to the dealer and get a factory gasket, DELCO synthetic rear-end oil and DELCO limited slip additive. Wipe as much of the old clutch material and smudge as you can and check for foreign debri. Fill the additive after the first jug of rear end lube to ensure the littel container of additive gets entirely put in. Fill with lube to it's oozing out of the fill plug.
I worked in theGM St. Catharines Components plant and the guys in the lab told me this. It's now closed and outsourced to American axle.

[1500ExtChevy]

I was gonna say I bought a 2005 Silverado Ext. Cab about 3 days ago now bought (3-6-10) and when braking doesnt do it but taking off you hear the clunk. But if you come to a stop and slowly take off theres no noise. I've noticed it but havent done much about it well it being 3 days old but I just watch myself as far as the take off by taking it slow which is quite the challenge.

[derekj]

I would suggest checking the carrier bearing.