Just bought 2002 avalanche 5.3 4wd autotrac np246, 4l60e, 65000 miles. had a rubbing noise (paid in concequence), sound louder when turned left. front hub bearings changed, no difference. checked fluid transfer case, and ounce, no leaks, filled smurf blue autotrac 2 went for drive, still a hum wether in 4hi-2wd-4lo so put in drive-2wd to come home pushed the gas a little and all of a sudden--HUGE clunkclunkcluk, i mean HUGE. even not moving in drive-clunkclunkcluk, put into neutral-ok,reverse-ok, park-ok...back into drive clunkclukcluk. put into reverse and drove all way home, even up steep driveway,in reverse no problem. Put on stands and all same symptoms...not spining foot on brake, just into drive from neutral drive..HUHGE clunk clunk cluk..put tcase into neutral...still big sound when put into drive, not reverse.what can this be transmission too? 4l60e...or can tcase planetairies work only in 1 direction if broken?

SOURCE: Will not go into reverse/05 chev avalanche

chances are you have a transmission problem. If its just reving it means the transmission isn't catching. I would take it to a transmission specialist right away and be sure to call the seller. I would ask for your money back or have the seller pay for the repair cost, which may be a lot. Advice for the future: Always test drive the vehicle so you don't get ripped off.

Douglas Smith

• 3 Answers
• Posted on Oct 16, 2008

SOURCE: Had transfer case rebuilt and I can't find a definite answer to what fluid it uses.

www.mygmlink.com has the answer and many more items for sale like a owners manual or service manual. I am pretty sure it is ATF though. I have not had to take mine apart nor add any fluid.

SOURCE: 2002 Chevy Silverado clunking noice when shift from 2wd to 4hi

It is somewhat Normal Depending on how Loud the Clunking is. This is a Common Complaint on the Chevy 4x4's. I have verified this through the Dealerships here in Oklahoma and they all say the Same thing But, I am with you, They should go into 4x4 without that Clunk for as much as we pay for them.

SOURCE: 1996 suburban makes grinding noise in 2 wheel drive

sounds like the clip on the rear output shaft its probably broke. do this by removing the rear driveshaft, and the tail of the transfer case, there are 4 bolts holding it in place. then grab the output shaft and see if it has any front to back movement. if so pull it all the way to the rear and you should see a groove at the front part of the shaft where the clip goes. Then you should find the pieces fo the clip in the tail housing. One person said he found the replacement clip at a local tranny shop. I am calling the dealership parts counter for a new clip for my 97 Tahoe tomorrow. Hope this helps..

SOURCE: chevrolet truck 4wd switch blinks

If they are blinking I believe it means that there are fault codes present in the pcm. You need to get the computer scaned to see if there are an codes present. If you live near an Autozone or Checker autoparts they can scan it for free.