Roaring noise motor

I have a 97 S10 chevy blazer, 4x4 manual, V6. When I spead up over 55 mph and let go of the gas, my truck turns into a mean son of a b$%@h lion , roaring to all the traffic to move the hell out of the way :lol2:. Its not the converter, its new. It only roars when you let go of the gas at high speed. As you speed up, the noise steadlly goes away. When going below 40mph or so, there is no noise even if u let go of the gas. Now, it does go into gear normally and smoothly even when starting at a red light then speeding up. Even at 50 or 55, you won't even feel the gear, so smoothly, but the noise is starting to bother me. I dont' think its the transmission or tranny..or (I dont' know all those part names). Any pros out there have experienced this. Please help me, I'll do whatever it takes to fix it..Where should I start checking? :confused:

Possably the clutch fan? i know my blazer kinda roars while speeding up when the motors cold, but fades away as i speed up more
hth,
Rick , ore

Noise in front or rear?
Got any bad tires?
Does turning the steering a little change the noise?
Is it locked in 4W drive?
Does engine RPM change noise or MPH changfe the noise?
http://www.differentials.com/install.html

its not the tires. OK, let me try it again. The sound only comes when you let go of the gas pedal, you start to hear first like a rattling chain followed by a WWWWOOOOOOOOOOOO sound. If you speed up a little, the WWWOOO sounds starts to fade away. I'm guessing the hub bearings. Again, you need to speed above 60mph or so for about 3 minutes, contently, otherwise the rattling sound will not come on nor the wwoo sound. But now, another problem I have. The truck dash lights flickered a few time when i wanted to turn the truck back on, and then no dash lights whats soever. the radio workds, the power windows work, the front/backlights work, but not the dashboard lights. So i turn the key, can hear the motor turn, but does not start? could it be the ignition switch or the ignition module inside the distributor? any ideas.

its not the tires. OK, let me try it again. The sound only comes when you let go of the gas pedal above 55mph, you start to hear first like a rattling chain followed by a WWWWOOOOOOOOOOOO sound as you slowdown. If you speed up a little, the WWWOOO sounds starts to fade away. I'm guessing the hub bearings. Again, you need to speed above 60mph or so for about 3 minutes, contently, otherwise the rattling sound will not come on nor the wwoo sound. But now, another problem I have. The truck dash lights flickered a few time when i wanted to turn the truck back on, and then no dash lights whats soever. the radio workds, the power windows work, the front/backlights work, but not the dashboard lights. So i turn the key, can hear the motor turn, but does not start? could it be the ignition switch or the ignition module inside the distributor? any ideas. OK, it might stuck on 4wd, but I'll let u know tomarrow. How can I disengage it if by pressing the 2wd button does not want to work, just incase.

97 is a bad year for ign switches.
Check for voltage to it and out of it.
On no start check for spark to plugs and good fuel pressure.

On noise is it more when you let up on it?
A rattling chain noise is not good.
If so check drive line and transfer case and rear end.

Here is a link to checking rear end noises.
http://www.differentials.com/install.html

Or a good trained ear may help you spot noise.

Up to date, I already got dash lights by replaceing a new ignition switch. I then notice the right rear shaft stained with oil, the whole right side of the differential was stained, NOT THE RIGHT WHEEL DISk. The oil stain was where the right axle housing meet the differential, is there a seal there or just 1 seal for the main shaft? So I put gear oil in the differential. Drive tested the truck, and it still sounds grinding, and wwoooooing sounds towards the front. I'm now checking for the from hub bearings. My question is how to you know if the bearings are defective? I took the main middle 13mm thread and washer, and then the round plate which holds back the bearings came off, is that normal? This plate is the front one which holds the five metal stick threads for the wheel sockets. I mean, you can actually see the bearings on the front, don't know if there are more behind the hub assembly. the bearings look perfectly round, and non are falling off, nor thing. The back of the hub where the bearings rotate also look shiny, and smooth, no cracks or anything like that. Should I just regrease the bearings and put the hub back? :confused: . maybe the noise is coming from the CV joints??:confused:

I also noticed the rotor brake being so HOT after a 10 minute drive. The rotor was a little stiff at first to move? could this be effecting the hub bearings? or the hub bearings be effecting the rotor Or the piston not working well, how to I test check?

UP to date...It seems like if I had two problems. The main chain noise was coming from the brakes. The piston wouldn't relax like it suppose to. My friend got a skrew driver and tried to push the piston inward by sticking the skrew driver through the top of the caliber. You have to put a little force when pushing the piston (thats normal) by the piston should go in slowly, smoothly. Mine was super hard that a tip of skrew driver broke. Anyway, check you pistons on the calibers and replace them if necessary. NOW, the noise is like a humming sound coming from the back or somewhere like that. It only sounds after driving for about 10minutes and when pressing on the gas pedal. The sound goes away when u let go of the gas pedal. What could it be? YOu might think the rear differential, but what about it??

UP to date...It seems like if I had two problems. The main chain noise was coming from the brakes. The piston wouldn't relax like it suppose to. My friend got a skrew driver and tried to push the piston inward by sticking the skrew driver through the top of the caliber. You have to put a little force when pushing the piston (thats normal) by the piston should go in slowly, smoothly. Mine was super hard that a tip of skrew driver broke. Anyway, check you pistons on the calibers and replace them if necessary. NOW, the noise is like a humming sound coming from the back or somewhere like that. It only sounds after driving for about 10minutes and when pressing on the gas pedal. The sound goes away when u let go of the gas pedal. What could it be? YOu might think the rear differential, but what about it??

Could be.
This site explains some rear end noise.
http://www.differentials.com/install.html



http://www.differentials.com/diagnose.html

Let us know how it goes.
MT