SuperchargedSS

iTrader: (24)

Just wondering if someone knows what the issue is, but I have 4.10 OEM gears (installed recently from 3.23s) with a TruTrac and T/A Girdle, etc. No problems with the gears, tuned good, etc. I ran 10 heat cycles no faster than 40-45mph over a period of 2 weeks.

Opened up the throttle a bit and climbed to about 90mph and head a loud growl/howl/rumble coming from the rear end. It is nowhere near a whine, just a loud noise. Just curious what this could be? Doesn't feel right tho?

Any suggestions?

GMCtrk

iTrader: (27)

well...you just had the rear end messed with...and now you've got a new noise....I'd say it's your rear end. How good was your installer?

SuperchargedSS

iTrader: (24)

well, I kinda figured that part out. Just trying to think of exactly what the cause of the problem was (i.e. backlash off, bad trutrac unit, typical noise with a high gear ratio).

Installer was pretty reputable.

02_Orange_D1SC

iTrader: (30)

im going to say probably a bad bearing either a wheel or a carrior or maybe the pinion only cause my old truck had a bad wheel bearing and it maid a growling noise but it only did it on the highway

SuperchargedSS

iTrader: (24)

crewcab does not have a carrier bearing, atleast not to my knowledge? I guess it could be the pinion angle, I'll have to look into that. Good call, didn't even consider that!

02_Orange_D1SC

iTrader: (30)

is that the first time you've had the truck at that speed since you lowered it?

SuperchargedSS

iTrader: (24)

lol, oh no. I have had that truck alot faster than that before the gears and still dropped.

It definetly has a 1-piece driveshaft.

02_Orange_D1SC

iTrader: (30)

well i figured you,ve had the truck faster then that since you lowered it but i just thought id ask lol

im thinking that its probably something inside the rearend because if it was the pinion angle the truck would vibrate not make a howling or growing noise it sounds like a bad bearing IMO

Coban

iTrader: (14)

You might have had the truck faster before, but now you are spinning the driveshaft over 25% faster to reach the same MPH. That could definitely bring out noise that you didn't hear before.

Now, your pinion angle might be a bigger factor because of this increase in RPM of the driveshaft.

05HD1500

strap it down on a chassis dyno so you can get the same speed and still walk around to locate the noise, sounds like a well spent $75 rather than changing parts that might not need to be or the labor to do so...