2002 gmc sierra 1500 4x4 whirring noise that gets louder ...

2002 gmc sierra 1500 4x4 whirring noise that gets louder as let off the gas pedal and decelerate and louder when braking between 20-30 mph Mechanic's Assistant: Where exactly do you think the noise is coming from? And how ...

2002 gmc sierra 1500 4x4 whirring noise that gets louder as let off the gas pedal and decelerate and louder when braking between 20-30 mph Mechanic's Assistant: Where exactly do you think the noise is coming from? And how long has this been going on? The rear axle I'm assuming but over a year a ago raining down the freeway after recently replacing differential fluid that rear axle it something made a loud noise in the back and fluid was running out of the differential for a couple of miles so we were able to stop and it got parked and eventually when funds were available to get parts if needed or a new differential upon opening the rear cover it was evident that the bearings or bad there was parts of them inside of the carrier and the pinion shaft. There wasn't any broken teeth on the gears of the pinion or the ring gear so decided to take a chance and leave that alone and just replace the bearings and shims for the carrier and crushed sleeve and pinion nut. Note when taking apart the differential the pinion shaft did not have a shim behind the gear head and the bearing and I could not find information that would tell me if there was supposed to be a shime there or not.. pinion depth was set preload for the pinion also and backlash or mesh was measured and sent to specs gear pattern was difficult to see with the compound that was provided with the kit but from what I could tell it seemed to be fine when everything is assembled and taken out to test at very small intervals for driving it sounded fine but shortly after 3rd time testing it started to sound noisy. Mechanic's Assistant: Are you fixing your Sierra 1500 yourself? What have you tried so far? Just the other day it had to be driven for about 15 miles and topped off differential fluid til it started to spill out the fill plug once it arrived to the destination I could smell your oil and after looking under the truck it's rear axle evidence of fluid sprayed all over the actual [exhaust](/topics-exhaust-gmc/) frame differential itself Mechanic's Assistant: Anything else you want the Mechanic to know before I connect you? I have also heard many different things about the rear axle assembly of the GM 10 bolt 8.6" differential 3.73 ratio also rpo codes are gt4 g80 Would like to not have to rebuild anything else that gets put in but from what I hear it sounds like this type of rear axle assembly forward slash differential is being rebuilt or repaired frequently so I would like to know if putting a stronger p is there a possibility of a 14-bolt 9.5 or 10.5 rear axle assembly that can match the 3.73 gear with six lugs and bolt up to my truck without much modification and or which axle from which vehicle would be compatible or the same length it has disc [brakes](/topics-brake-gmc/) as well