intermittent clunk in the drive line

[j cAT]

Originally Posted by CKENDZIORA

We had the truck on a lift we were tugging and pulling etc and didnt see, feel or observe anything unusual. Man i hate intermittent issues that is why I have grey hair.

GOOD !
I would replace the transfercase fluid ...use the proper fluid..tracII transfercase fluid at the GM dealership...need 3 QTS ..simple when vehicle is hot has been driven to heat up these fluids drain fluid , the fill using a qt sized hand pump and fill to the top of the fill hole...

after a few miles the clunking will most likely be gone..Like I stated I do this every 30,ooomi...these 4X4 vehicles need a lot of maintenence..

tighten these plugs to 15 ft lbs ...like a spark plug not too tight ..

If you see that the fluid is very dark / gray blue you needed this fluid replacement ...If black cross those fingers ...

the other item is the rear diff fluid ...replacement is the removal of the rear cover and cleaning out the box ,,this takes more time but this is the proper method to PROPERLY service this componet...only draining and filling is not a advised ..

[CKENDZIORA]

Originally Posted by j cAT

GOOD !
I would replace the transfercase fluid ...use the proper fluid..tracII transfercase fluid at the GM dealership...need 3 QTS ..simple when vehicle is hot has been driven to heat up these fluids drain fluid , the fill using a qt sized hand pump and fill to the top of the fill hole...

after a few miles the clunking will most likely be gone..Like I stated I do this every 30,ooomi...these 4X4 vehicles need a lot of maintenence..

tighten these plugs to 15 ft lbs ...like a spark plug not too tight ..

If you see that the fluid is very dark / gray blue you needed this fluid replacement ...If black cross those fingers ...

the other item is the rear diff fluid ...replacement is the removal of the rear cover and cleaning out the box ,,this takes more time but this is the proper method to PROPERLY service this componet...only draining and filling is not a advised ..

so the transfeer case lube is avalable dealer only then? the diff fluid was dark blue. thanks again.

[MikeD266]

Question jc et al...

Last time I changed diff and xfer case fluids I didn't have access to a fluid pump. To make it a bit easier to re-fill everything I got a couple of feet of clear tubing and water bathed the diff and xfer case fluid just enough to warm them up. Crawled under, threw the tube in the hole and had a friend squeeze the bottles until things were full. Double checked the levels an hour later when everything was ambient temp.

Any issues with this - aside from making sure that you don't "cook" the fluid?

[j cAT]

Originally Posted by MikeD266

Question jc et al...

Last time I changed diff and xfer case fluids I didn't have access to a fluid pump. To make it a bit easier to re-fill everything I got a couple of feet of clear tubing and water bathed the diff and xfer case fluid just enough to warm them up. Crawled under, threw the tube in the hole and had a friend squeeze the bottles until things were full. Double checked the levels an hour later when everything was ambient temp.

Any issues with this - aside from making sure that you don't "cook" the fluid?

the use of the small hand pump is a fast easy way to fill these.....its a small cost and last a long time ...

with stiff tubing of the correct dia you can adjust the suction tube to handle different sized containers....

when I change the tranny fluid in the 96 impala I use this pump to suck out a 1.5qts of fluid before droping the pan much less spillage..use a 6 ft long tubing ..stuck in the fill tube ....

[CKENDZIORA]

Originally Posted by CKENDZIORA

so the transfeer case lube is avalable dealer only then? the diff fluid was dark blue. thanks again.

ok changed the diff fluid yesturday all was good inside the diff no metal chips etc. auto shop teacher looked the truck over for me said the front shaft front joint seems looser than normal to him and to change it and see if that resolves the issue.

I will change both joints however as only doing "1" or the front only would seem counter untiuitive too me or half assed

[j cAT]

Originally Posted by CKENDZIORA

ok changed the diff fluid yesturday all was good inside the diff no metal chips etc. auto shop teacher looked the truck over for me said the front shaft front joint seems looser than normal to him and to change it and see if that resolves the issue.

I will change both joints however as only doing "1" or the front only would seem counter untiuitive too me or half assed

are you talking about the U joints on the fwd drive shaft ?

no such thing as looser than normal ....any U joint movement is a no no ...the U joint is in need of replacing....I thought you had done this ?

when you start this you must mark the driveshaft and yoke flanges ...I use paint...then on installing put back as it was ....

when ever you drop a drive shaft replacing both JOINTS is normal...also do not buy any CHINESE U JOINTS !

well anyway the transfercase fluid replacement you will see the 4wd selecting time much faster with the clean fluid ....takes a few miles of driving for this to occur...

[CKENDZIORA]

Originally Posted by j cAT

are you talking about the U joints on the fwd drive shaft ?

no such thing as looser than normal ....any U joint movement is a no no ...the U joint is in need of replacing....I thought you had done this ?

when you start this you must mark the driveshaft and yoke flanges ...I use paint...then on installing put back as it was ....

when ever you drop a drive shaft replacing both JOINTS is normal...also do not buy any CHINESE U JOINTS !

well anyway the transfercase fluid replacement you will see the 4wd selecting time much faster with the clean fluid ....takes a few miles of driving for this to occur...

yes is did check everything but the issue was still there and asked my sons autoshop teacher to look the truck over. He said the ujoint seemed looser than he would like it and told me to start there but wasnt totally convinced it would solve the clunk but it was a starting point.

Chinese u joints? who sells those so i stay away from them?

[j cAT]

Originally Posted by CKENDZIORA

yes is did check everything but the issue was still there and asked my sons autoshop teacher to look the truck over. He said the ujoint seemed looser than he would like it and told me to start there but wasnt totally convinced it would solve the clunk but it was a starting point.

Chinese u joints? who sells those so i stay away from them?

well this is probably why he is an instructor ...U joints must not have any play....this causes vibration .....I just did a U joint on this same drive shaft and the replacement U joints are made in USA....replacing as I believe I previously mentioned need both replaced, painting the drive shaft / yoke to ensure it is assembled as removed is important....this should correct the problem....

the new U joint will need grease every oil change ,,,,this usually means it will last the life of the vehicle...

[MetzO7]

"Some times bumpy roads bring it on yes, the steering column has a groan in it when going lock to lock that has been there for a while too? i do not feel the issue on take off or gear shifts during normal driving but to make it fun it's intermittent"

Found this TSB mayb it will help you out I remember reading something about another TSB for the rear drive shaft slip yoke causing a similar consurn I'll have to do some more looking around to find it

TECHNICAL
Bulletin No.: 03-03-09-002C
Date: June 02, 2009
Subject: Rear Leaf Spring Slap or Clunk Noise (Replace Spring Inserts)
Models:
1999-2009 Chevrolet Silverado 1500/2500 Series Pickups
2000-2009 Chevrolet Suburban 2500 Series
2002-2009 Chevrolet Avalanche 2500 Series
2003-2009 Chevrolet Express 2500/3500 Vans with 8500 GVWR (RPO C5F), 8600 GVWR (RPO C6P) or 9600 GVWR (RPO C6Y)
1999-2009 GMC Sierra 1500/2500 Series Pickups
2000-2009 GMC Yukon XL 2500 Series
2003-2009 GMC Savana 2500/3500 Vans with 8500 GVWR (RPO C5F), 8600 GVWR (RPO C6P) or 9600 GVWR (RPO C6Y)
Supercede:This bulletin is being revised to add the 2009 model year. Please discard Corporate Bulletin Number 03-03-09-002B (Section 03 - Suspension).
Condition
Some customers may comment on a rear leaf spring slap or clunk noise. This noise is most apparent when the vehicle is operated over irregular road surfaces.
Correction
Important
DO NOT disassemble the main pack on the leaf spring or remove the bushing from the spring.

Insert - P/N 15604067

Insert - P/N 15247030
Verify that the rear leaf spring inserts (1) are present on the leading and trailing ends of the overload spring (second stage leaf). The insert may have broken apart from wear and fallen out. If the inserts are not present, install new ones.
Important
On some models, the vehicle may have to be raised to allow the springs to separate enough so the insert can be installed.
Parts Information
Important
Technicians should refer to the Parts Catalog when ordering the insert.

Warranty Information

For vehicles repaired under warranty, use the table above.

[MetzO7]

Here is the TSB for the rear drive shaft slip yoke

Bulletin No.: 01-04-17-004B
Date: January 05, 2005
TECHNICAL
Subject:
Clunk, Bump or Squawk when Vehicle Comes to Complete Stop or Accelerating from Complete Stop (Replace Rear Drive Shaft Nickel-Plated Slip Yoke)

Models
Supercede:
This bulletin is being revised to add Cadillac Escalade (Old Style) 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.
Diagnostic Tips
There are several resources in the electronic Service Information System which can provide the technician with information on diagnosis and repair of clunk conditions, and fix the customer's vehicle right the first time without unnecessary parts replacement. Some of the documents available in SI include:
^Symptoms - Propeller Shaft
^Knock or Clunk Noise
^Rear Drive Axle Noises (SI Document ID #700580)
^Launch Shudder/Vibration on Acceleration (Replace Propeller Shaft and Install a New Pinion Flange/Seal), Bulletin # 02-04-17-001
^Information on 2-3 Upshift or 3-2 Downshift Clunk Noise, Bulletin # 01-07-30-042
^Driveline Clunk When Stopping (Reprogram Powertrain Control Module (PCM), Bulletin # 03-07-30-028
Correction
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.
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.
Note: 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.