8" rear on 66 mustang knocking

[handyhand]

Well this is my first post to what seems like a great forum to be a part of! I hope someone can help me out. I have been hearing a knocking or clunking sound from the left side of my rear wheel or rearend area of the car, I can olny hear it when I am off the throttle at a coast with no brakes. To my frusteration, I have had the rearend totally re-built by a shop with new gears, upgraded to 3:00 from 2:80, new spider gears, everything. When I got the car back the knock was still there! Then I had new axle bearings and oil seals installed by a machine shop and the axles tested for straightness. Th knocking still there! Brakes seem fine, everything under there is nice and tight, the ONLY thing I can see what is wrong is when I grab the tire and "rock" it back and forth, I hear knocking! The tire and rim are nice and tight, Seems to be coming from the end of the axle that sticks into the center pumkin, I have no idea what that end of the axle sticks into in there, but it is definatly knocking around in there where it is causing some noise, and I can actually 'feel' it when I have my hand on the back of the housing, what I dont get is all this is new and the axles where checked out and seem fine, so what should I check for next or do?? Thanks for any info and input gang! James

[94svt5.0]

Welcome to the boards! Not real sure on your "knocking problem" Best I know to do is take the rear diff. cover off and take a look while someone rocks the wheels, and see if there is some unusal movement. Keep us posted.

[HiFlow5 0]

Welcome to the board, we're to help!

At first, before I finished reading your post I was think that you bushing were shot in the control arms, but as I read on I have another theory.

A lot of times when you have a gear swap done, places recommend that you install and alum driveshaft. This helps eliminate any vibration and excess noise associated with a steeper gear.

Another area to note are the yokes on the driveshaft, if you car still has the orig. d/s from 66, or you replaced it with a used one, then chances are the yokes are shot!

And finally, if the pinion gear was not installed propperly and the backlash is off there will be a lot of play in the drive line. From what you said, You can only hear the noise when coasting, I think this might be your problem. As when you are on the gas you putting more power to the ground and the drive line is tight, but when you coast there's less tension in the drive line, cause things to slop around more.

[handyhand]

Hey thanks for the help you guys, ya, I think a trip back to the shop is going to be warrented here, I will have them take another look at it tomarrow, I will certianly keep everyone posted! Thanks again! James.

[vortech]

that knocking is a broken gear tooth. Its happened to me before----and it also sounded like knocking on mine.

[handyhand]

Well, last wek I got the car up back to the shop that did the rear-end rebuild, they beat around the bush and said everything from rear axle bent or brake shoes rubbing hitting the drums, so I was not going to get anywhere with them as far as tearing into the 3rd. member again to double check their work. So I found a specialist in differentials here in Phoenix and had him tear the 3rd memeber down and he found that the "Carrier" in there, had some slots or holes that were too large or even oblonged, so he replaced that and slapped it all back together, he was not happy with the back lash settings and alot of other settings, so he redid them properly, got everything back on the car and that damn left tire still has play in it!!!!!!!!!!!!!!!! The only thing that it can be is the rear housing that where the axle bearing sits in is too big or oblonged and letting that bearing clunck around while I wiggle the wheel or drive it at coast. My next step is to get a new rear housing from www.currieenterprises.com , and get it on there and hope that does it, in my thinking its the only thing left to replace! The housing is only $139.95, so its not a real big setback thank god! I will certainly keep us posted. Thanks for the help gang.

[cheeda]

Did anyone ever hear what was finally done to solve this problem?