Denali Issues- Newbie

Just purchased a 2003 Denal XL with 18k on it....noticed a Humming noise on acceleration only above 45mph. Dealer replaced front diff. a few days later.

Majority of noise is gone...however, I still hear a faint hum at about 45 mph and above. Anybody have any suggestions?

Also, the brakes SUCK on this thing. The dealer looked at them and said everything is fine. However, the rotors were replaced with Stillen drilled rotars so the dealer wont touch it. The brakes are extremely soft and slow to react. My wife drives it so I am concerned? Anyone have any suggestions besides replacing the rotors? Thanks!

Did the dealer try to pass off the humming noise as being a by-product of the Denali's AWD system? There might be some merit to that claim...

As far as the brakes are concerned--yeah, the brake pedal feel on my stock brakes are a bit on the soft side too--for comparison, the stock pedal feel on my '03 YXL was a bit firmer; I may have to have the dealer bleed the system to see if it helps. Short of perhaps (re)bleeding the brakes, which may or may not resolve the pedal feel issue...you probably would need to upgrade the pads, calipers, and brake lines in order to obtain a noticeable improvement in braking performance and pedal feel on your Denali. My bro upgraded the entire front brakes (pads, rotors, calipers, lines) and rear brakes (pads and rotors only) on his Esky to Brembos and he said it was a night and day difference in braking performance between the Brembos and stock.

Thanks for the info...actually, this weekend I took it into a brake shop and they said that the Stillen drilled rotors were most likely the problem since they are not made for the way i drive and frankly should not be put on a Denali...I had them replace the rotors...the inner pads were also gone. Apparently, these "Rambo" rotors have the tendency to eat up pads...

In short, braking performance was greatly improved...why someone would put these type of rotors on a denali is beyond me. Remeber, i bought it used.

As far as the humming is considered, after the 2nd time going back to the dealer and insisting that i go with them on the test drive, they finally agreed that the front diff was making noise...so they replaced it. It is 100% better; HOWEVER, i still hear a slight hum at around 45 mph.

Someone had mentioned that the tranny fluid can have a lot to do with resolving this. Although, I cant seem to find the link anymore to the solution.

Hi ; The only two reasons that come to mind for a stillen brake upgrade on a denali would be (1) he rode the truck hard and braked even harder, (2) he had 24" (canastoga wagon) wheels on it, you know, "donuts on a dinky toy". But you are correct in your assumption that drilled rotors eat pads. They are normally reserved for competition applications...High performance- short life span. As far the hum goes...a minimal of hum is normal from any 4 wheel drive system, and not to mention your tire tread configuration could be to blame, even highway treaded tires hum. Hope this helped :2cents: Good Luck ,Mike

Hi ; The only two reasons that come to mind for a stillen brake upgrade on a denali would be (1) he rode the truck hard and braked even harder, (2) he had 24" (canastoga wagon) wheels on it, you know, "donuts on a dinky toy". But you are correct in your assumption that drilled rotors eat pads. They are normally reserved for competition applications...High performance- short life span. As far the hum goes...a minimal of hum is normal from any 4 wheel drive system, and not to mention your tire tread configuration could be to blame, even highway treaded tires hum. Hope this helped :2cents: Good Luck ,Mike


Thanks Mike! He did have 24's on it....the hum is only on acceleration and from 45 to 55mph, which would exclude tire noise. I am suspicious since I have already had the diff replaced once.

Thanks again!