BlackBirds

iTrader: (24)

About a year ago I replaced the four bearings in the rear end and the two axle bearings. Now I'm getting some rear end noise when I'm driving over 60mph. I'm thinking my pinion nut has backed out a bit and needs retightened. How do I know how much to tighten the nut?? All the threads and write-ups say to tighten the pinion nut until you measure ~20 inch pounds of drag when spinning the pinion. I can't use this measurement though because my rear end is completely assembled, wheels and all, and I have used bearings in it as well. Is there any way to tighten down the pinion nut with a completely assembled rear and get it to the correct preload??

I just don't want to have to take the differential out again...that was a PITA...

BlackBirds

iTrader: (24)

anyone? theres gotta be a procedure or torque rating, I'm sure shops have to change out that rear seal from time to time and to get to that you have to take the pinion nut off but leave the rear fully assembled.

jay_lt4

iTrader: (4)

if you used a crush washer when you set up the pinion bearing pre-load,, they are a 1 time use only and if the pinion nut did come loose you will need to replace the crush washer and re-set the pinion bearing pre-load

if you used a solid pinion spacer you can just re-torque the pinion nut, if damage hasnt already happened to the bearings

the gm procedure for replacing the pinion seal,, you measure the pinion rotating tq with the brakes/ rotors removed so you are just free spinning the carrier/ axles,, get that measurement, remove the pinion yoke, replace the seal,, then tighten the pinion nut to your original rotating tq measurement + 3 inch pounds tq.

(this really doesnt apply to you because you no longer have an accurate starting point to measure your rotation tq)

BlackBirds

iTrader: (24)

i did use a crush sleeve....sigh....

oh well, thanks for the info!

BlackBirds

iTrader: (24)

for anyone that might come across this thread in the future with the same problem, what I figured I could tighten the pinion nut down an eighth of a turn, put the driveshaft back on and take it for a drive to see how it sounded. If the noise was worse, the nut was too tight, if it was quieter, then the nut was too. I would then adjust the nut as necessary and re-do the process. This is what I did, and it worked! My rear is now quiet.

Note to anyone that might try this: Only turn the nut an eighth of a turn at the most each time! Small differences in pinion nut tightness make a huge difference in the pinion bearing preload. This method may be very ill-advised, but it worked for me, and if you have the patience for it, it will probably work for you too.

ls1anxiety

Thankyou for the help @blackbirds

manzo81maro

I just replaced my pinion seal in my 2002 SS and I'm pretty sure I accidentally over-tightened the pinion nut...first mistake was not marking the nut/yoke/pinion assembly before I took it off, then after re-installing the yoke, I got on the pinion nut with an electic impact gun and tightened to where I thought the correct amount of threads were exposed...checked the rotational resistance and it felt way more difficult to turn than before disassembly...backed off the nut and pulled the yoke out until the resistance felt better and then tightened the nut again, but I'm pretty sure this won't solve my problem...will I have to take apart the rear and install a new sleeve or is there any other way I can set this preload properly and be safe?