clunk not gone

[scottac]

I drainded and refilled the front and rear diff and the T-case this weekend. front filled with 80W-90 gear oil and the rear filled with 75W-90 sinthetic with the friction modifier additive. the T-case was filled with Auto track II (Blue) fluid purchased from my GM parts department.

 

I had read on here somehere that others who have had this clunking symptom had fixed it by replacing the T-case fluid. well my clunk did not go away.

 

I am pretty sure it is the T-case too. Specifically when shifting to reverse. and gets prgressively louder as you cycle to 4-Hi and then to 4-Lo. the only time it makes a noise going into drive is when you shift really fast from either Neutral or Reverse.

 

Any suggestions as to what my be wrong. GM suggested changing the fluids in the diffs and T-case (per service department rep).

 

I just hate that sound, it is really depressing.

 

thanks in advance.

[Lou'sZ]

Have you tried greasing the driveshaft splines, where the driveshaft goes into the rear of the transfer case?

[scottac]

no I haven't tried that. what sort of lube would you recomend.

 

besides. It really sounds like it is the T-case. the fact that it gets louder as you cycle through 4-hi to 4-lo tells me that it has something to do with the t-case.

 

has anyone else had this clunk that I am talking about?

 

thanks in advance for all replies.

[Lou'sZ]

Others can correct me if I'm wrong, but I think any good quality chassis or suspension component grease will work. You have to remove the driveshaft from the vehicle there are no zerks for the splines. Others have reported that this fix can sometimes be temporary-the noise will eventually come back, then you grease it again. Should take 1 hour or less, just remove the bolts holding the u-joint at the rear of the driveshaft to the pinion cradle and pull the driveshaft straight back. Hold the unsecured u-joint end caps to prevent them from falling off and rolling into the dirt! You may want to place the u-joint back into the cradle with the same orientation as it came out. Mark it with a sharpie or pen.

[Black02Silverado]

I'm I wrong or could it be the slip yoke. I had a clunk and had the dealer look at it and they changed out my regular yoke to the nickle plated slip yoke and it solved my problem. I even got a new universal joint out of it. It is part of the replacement kit. Worth a try. That is if that is it.

[Markeaux]

Yeah I've heard the nickel yoke has fixed the clunk for many ppl.

[scottac]

I just did a little research and the problem that is described by other people is Identicle to the problem I am having.

 

I just need to get a part number and order it now.

 

thanks.

[tyudi5bs]

I wouldn't plan on buying the nickel-yoke, for the 1500 series it runs $150 shipped from gmpartsdirect. The 2500 is $165.

 

Part # for 1500 is 12477702

2500 - 12477704

 

There's a TSB out that addresses the issues and the correction is to replace the yoke with the above nickel-plated yokes.....as long as you're still under warranty. Otherwise you will have to buy them yourself. I haven't gone to the dealer to try and get mine replaced yet, doubt they will since my trucks lifted 6"

 

The bulletin number is: 01-04-17-004 dated october 2001. If you do go, and let them know that you have the problem addressed in this bulletin they'll give you much less hassle, usually they'll just throw in the new kit if they have one in stock and let you be on your way. I've heard of a lot of people going in for stuff like this and not knowing the facts, and the dealer gives them the run around and tries to charge them.....hope this helps.

[hihosilver]

I've taken my truck in to the dealer 3 times now for the driveline clunk. They put in the nickel plated slip yoke when I brought in the tsb the second time. It fixed it for about a week. Now it's as loud as ever. The 3rd time in was just last Tuesday. I went to the dealer to get the regulator replaced in my drivers side window and told them about the clunk again because I'm at 35k miles. They said they have done everything and can't fix that. They put in some new inserts and insulators somewhere in rear suspension saying they were a little squished. I filed with the BBB a month after I bought the truck and got a 100k mile powertrain warranty from GM for free. Has made me feel better about it I guess. It still annoys the h*ll out of me.

[99silveradoz71]

hiho, did you try replacing the transfer case fluid with the newer blue stuff that GM has out. I also had clunk and first had the yoke splines greased, then had the nickel yoke with no additional problems, then I switched the fluid just as regular maintanence. I believe the blue fluid was part of a tsb on the issue too.

[hihosilver]

hiho, did you try replacing the transfer case fluid with the newer blue stuff that GM has out.  I also had clunk and first had the yoke splines greased, then had the nickel yoke with no additional problems, then I switched the fluid just as regular maintanence.  I believe the blue fluid was part of a tsb on the issue too.

Yes, It already had that in it from the factory and then I changed it at 25k miles.

[scottac]

I actually changed over to the blue stuff about a year ago and changed the fluid again due to advace from this and other forums. it didn't help my clunk at all. The dealer tried to say it was the rear diff making the clunk but I showed him my reciepts that I had just changed the front and rear diff fluids like a week prior to bringing it in trying to fix the problem. He didn't have too much more to offer. I will just go to a different dealer anyway the guy was really rude and I don't want to give them any of my money anyway.

 

Oh, yeah, I have about 60,000 on my 99' silverado 4x4 if anyone else has further advice.