Differential shifted

[78TA_In87]

I was told that my differential shifted, as indicated by these 2 photos.  Is this a simple fix that just requires the bolts under the springs to be loosened, re-shifted so the bolt is going through the center of the hole, then tightened back up?  Looks like the bolt may not be long enough to go through the hole enough to keep it from shifting under the leafs ( PTFB Heavy duty tie down leaf spring plates is what is in the pictures) .  And what would have caused something like this to happen?  The car was maybe driven 60 miles after the install, and most of that was highway miles from the shop back to my home.

[78TA_In87]

Do I just need to loosen the U bolts on the springs and push the axle back into place so that bolt goes into the center of the hole?  Is this easy to do?

[firebirdparts]

Seems to me you have to try that.  I don't know why it didn't stay put, though.  I guess the original rubber is broken up some and maybe it didn't index in that hole all that convincingly.

[78TA_In87]

Seems to me you have to try that.  I don't know why it didn't stay put, though.  I guess the original rubber is broken up some and maybe it didn't index in that hole all that convincingly.

Thank you for your reply.  I will try to see if I can replace that rubber part (the springs are from PTFB).

[Wallington]

Is one tyre a lot closer to fender front/rear than it was before compared to other side?

[81Blackbird]

Mine didn't slip like your but it was on its way.

https://imgur.com/Xk9OlMd

https://imgur.com/3f8s0Mr

[78TA_In87]

Mine didn't slip like your but it was on its way.

https://imgur.com/Xk9OlMd

https://imgur.com/3f8s0Mr

Do you know what caused it to slip?  I hope the people did my LS3 swap measured correctly what the new drive shaft length would have to be before they purchased the new one.  It wouldn't surprise me with so many things that did wrong and the many new parts they broke.  Does this seem like maybe the diff could have been off and maybe that is why it is not centered?  This is my big fear about this.

[78TA_In87]

Is one tyre a lot closer to fender front/rear than it was before compared to other side?

I just measured and they're off by 1 inch! 

I measure the gab between the back of the wheels and the bottom edge of the wheel well.
Driver's side has just a bit more than 2 1/2" gap. 
Passenger's side has a 3 1/2" gap.

[Wallington]

To be expected, the rear is now out of alignment due to the new slightly off-centre leafspring mount. Keep that in mind as a good adjustment to aim for when they match again.  Possibly didn't match before but it's a start. You may be able to add a threaded sleeve onto the end of the leafspring bolt to use as an indicator and centralise against general movement.

[NOT A TA]

When you reset the rear, measure in an X manner from points on the body and/or frame to be sure the rear is square with the uni-body (not just the spring bolt is in the hole).  When tightening the U bolts and/or T bolts draw the nuts up evenly a little at a time to keep the plates flat and avoid squeezing the rubber pad more on one side which pushes the rear end out of square. DON'T OVER TIGHTEN THE SHOCK PLATE NUTS, the torque spec is lower than most people would think. Also watch for difference side to side when you reset the rear and try to get it even.

[78TA_In87]

To be expected, the rear is now out of alignment due to the new slightly off-centre leafspring mount. Keep that in mind as a good adjustment to aim for when they match again.  Possibly didn't match before but it's a start. You may be able to add a threaded sleeve onto the end of the leafspring bolt to use as an indicator and centralise against general movement.

Thank you. 

By "slightly off-centre leafspring mount" you mean the mounting installation was not done properly or do you mean the leaf springs themselves are not centered?  I think I know but just want to be sure.  And the drive shaft is probably the correct length (I accidentally referred to it in my previous reply as the differential) ?

[78TA_In87]

When you reset the rear, measure in an X manner from points on the body and/or frame to be sure the rear is square with the uni-body (not just the spring bolt is in the hole).  When tightening the U bolts and/or T bolts draw the nuts up evenly a little at a time to keep the plates flat and avoid squeezing the rubber pad more on one side which pushes the rear end out of square. DON'T OVER TIGHTEN THE SHOCK PLATE NUTS, the torque spec is lower than most people would think. Also watch for difference side to side when you reset the rear and try to get it even.

Thanks so much for the tips!

I only have a small metric torque wrench for my bikes (bicycles).  But have been in the market for working on the car too. 
Been thinking of this one, a 1/2 inch 20-250 ft-lbs.
https://www.amazon.com/gp/product/B00C5ZL1NS/ref=ox_sc_act_title_5?smid=ATVPDKIKX0DER&psc=1

Any other sizes  (1/4, 3/4 or other size) to get?

[Wallington]

No, I just meant the issue you have with the leafspring mount no longer being centred, therefore twisting the axle out of alignment and causing the fender gap differences.

[81Blackbird]

Not sure but the thought of not tightening the bolts, U-bolt and T-bolt evenly may have been part of my issue and not paying attention to the fact the rubber nipple was not placed over the bolt that holds the springs together wasn't seated properly in the shock plate.

[glenn911]

Every 2nd gen I have owned (7) has had the rear axle shifted to the driver side.  Factory original or ground up resto, didn't matter.

[78TA_In87]

Thanks Everyone for replying!  I feel much better about being able to do the job now, and less worried about extra things that may need to be done to fix this (although I will be cautious, just in case).  You guys ROCK!!!