05 Z71 transfer case clunk

[bmchevy1979]

Well I recently purchased a 05 Chevy Silverado 4x4 and i am getting ready to service the transfer case and axles on it but on the transfer case when you are shifting from high 4wd to low 4wd it makes a clunk that is fairly loud it doesn't do it any other time just when shifting from high to Low and Low to High. 4wd functions perfectly in both its just fairly loud when switching I'd like to know if it's something I should be concerned about or not the truck is pretty much stock and I plan on using it off road quite often mostly at the sand dunes and in the snow it looks to be the original fluid in the transfer case it's fairly dark compaired to the bright blue that the Autotrak ll fluid is so is it possibly that it's just gummed up from not being used very often and the fluid being old

[WestButteTruck]

I figure it's normal, every push button 4x4 I've owned (5) have done this going into 4 low. And typically I am on level ground, stopped, in neutral.

[68C15]

I'm still trying to figure out why they put 4 low in a passenger truck.

[WigglesTheHoly]

68C15
Because sometimes we like to pull bushes out of the front yard....atleast that is the last time I used mine. lol

[allengator]

my '04 Tahoe has done that since new.... so did the '02 before it....

[kaycee]

transfer case pump rub it will eventually crack your rear case and cause a leak or replace the back half case. A cheap easy fix for this is to get a pump rub plate to prevent this $30 its not hard at all to put in ther is another kit to use but it is $75 and a little more advanced installation. There are several videos on you tube on this procedure . If you plan on keeping the truck or 4x a lot this is a must do

[WigglesTheHoly]

Here is a good video on it. https://www.youtube.com/watch?v=bOyZ...nPCz4Y&index=2

[treveiger]

I thought the pump rub was a issue for the hds only? Does it effect all transfer cases? I'd say the clunk is normal, try it on gravel with the truck in neutral to see if it reduces the noise.

[clinebarger]

Originally Posted by treveiger

I thought the pump rub was a issue for the hds only? Does it effect all transfer cases? I'd say the clunk is normal, try it on gravel with the truck in neutral to see if it reduces the noise.

It affects all GMT800 trucks. For example a 1500 would have NP261-LD & a 2500 would have a NP261-HD....The only difference between the 2 is the Input Gear (27 spline vs 32 spline).

[treveiger]

That's good to know, thank you.

[kaycee]

My 01 1500 had it and it has the NP 246 x-CASE

[richards72chevy]

I have an 02 Silverado 1500 push button 4wd would it use the autotrak ll?How many quarts?Should it be changed after the truck has been driven a little bit or can it be changed cold?

[clinebarger]

The Auto NP246 is also effected by Pump Rub.

NP246 uses 2 Quarts of Auto Trak II Fluid.

NP261 & NP263 take 2 Quarts of Dexron III ATF.

[AnotherWs6]

My 2000 with 308K miles has always done that.