Mystery Backlash?
Mystery Backlash? Ok, my 2000 SS with M6 has a factory stock rear end. I had gears at one point but for reasons not important I put the rear back to stock....that is all the stock shims, bearings, gears, diff etc. The rear has been fine for about 20K miles. Well in the last 2 weeks it has progressed from perfect to making so much noise during deceleration in gear that its unberable. So last night I took it apart to replace the diff. berarings and the pinion bearing. So I decided to go ahead and check the backlash before I removed the diff. just as principal. Well I didnt even need the dial indicator because there was virtually NONE. I also checked the wear pattern and its not real bad at all on the gears. So I went ahead and removed the Diff. to look at the diff. bearings. They look fine and the shims all look fine. I dont see anything that would have caused the rear to loose all of its backlash? Anyone have any idea where it went? I have not removed the pinion yet. But it feels fine to spin and does not seem to have any slop? OUgh yeha the rear ws still full of lube and there is no metal or anything worth mentioning in it?
Thanks for your help
Thanks for your help
Last edited by ssjunkie; Dec 1, 2006 at 04:06 PM.
Ok, not that anyone cares apparently. As is apparent by the number of replies I got. But I found the problem when I got home yesterday I pulled the drive shaft out to check the pinion preload and to my suprise there was none. Actually the pinion would even wiggle a bit. So I tightened up the pinion nut about a 1/2 a turn and checked the preload with my inch lb. torque wrench. It was right at about 15 so I was good to go. I reinstalled the diff. and checked backlash. Right at .008 again. Reinstalled everything and I was good to go. The rear is quiest again. Im not sure what caused the pinion nut to work loose but hey im just gonna drive it.
Ough yeah I did take a punch and ding the pinion nut this time. Hopefully it will stay put.
Ough yeah I did take a punch and ding the pinion nut this time. Hopefully it will stay put.
I care man, i care... did you install a new crush collar so this would not happen again? or is it a solid pinion spacer (which i would not use because I personaly would not know how to shim it) as you know, the crush collar crushes to get both the inner and outter pinion bearings to seat properly while still maintaning the proper ammount of preload, I believe the wrong shims on a solid pinion spacer would keep the bearings from seating if there was too much shim and not apply the proper preload if there was not enough shim, maybe im not understanding the whole solid pinion spacer thing but IMO unless you are rebuilding your rear for fun every week and dont want to pay 99 cents for a crush coller every time the solid pinion spacer is yet another waist of money to fall in the abyss of pointless products for your vehical
If you reused your old crush sleeve, that was definately your mistake. The crush sleeve provides a huge clamping force on the inner bearing races while keeping the front & rear bearings spaced "just right" to obtain proper preload. Even just loosening the pinion nut (say to replace a pinion seal) relaxes this clamping force and there is no way to get back to where you were (that delicate balance of huge inner race clamping force and preload) without replacing the crush sleeve. You may have removed the slop in the pinion that caused your backlash to disappear, but I doubt that by re-tightening the pinion nut that you've re-estabilished sufficient clamping force to keep things from moving around again under load, despite getting back to the proper preload.
20K miles ago when I put it back to stock it got a new pinion seal and crush colar.But I did not replace it this time.
But....To be honest, I was not sure if I had any bearing damage, gear wear or numerous other problems that could have been caused by driving it with the pinion moving around, so I decided to go ahead and tighten it back up and try it, to see if the noise was gone. I figured the worst would be I lost a couple hours time and a couple courts of gearoil.
Now that it turns out everything is fine I agree the proper thing to do would be to get a new seal, crush colar and pinion nut. Then go back and replace them...but being its my car and my time and the optimist that i am....F'it im gonna drive it like I stole it and if it starts making noice again. I know what I gotta do and if it breaks so be it, I will just have to fix it.
But....To be honest, I was not sure if I had any bearing damage, gear wear or numerous other problems that could have been caused by driving it with the pinion moving around, so I decided to go ahead and tighten it back up and try it, to see if the noise was gone. I figured the worst would be I lost a couple hours time and a couple courts of gearoil.
Now that it turns out everything is fine I agree the proper thing to do would be to get a new seal, crush colar and pinion nut. Then go back and replace them...but being its my car and my time and the optimist that i am....F'it im gonna drive it like I stole it and if it starts making noice again. I know what I gotta do and if it breaks so be it, I will just have to fix it.
Last edited by ssjunkie; Dec 1, 2006 at 04:15 PM.
