8.8 rear end (both tires are locked together)

StrollingBowling

New Member
Mar 26, 2018
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I did a gear change last week. Took out the 410 and installed a 331 in 90 GT. Drove it Saturday without any issues. Sunday I drove it and notice when turning there was a popping sound that you could feel coming from the rear of the car. Jack the car up and found that you can not turn one tire and hold the other one still. Any idea what would cause this. Did not have any issues before the gear swap. Everything went together easy
 
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Here are the photos. I don’t see anything out of the normal but have never taken this type of diff apart before
 

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How long ago was this done? Was the pinion gear done at the same time? Re-measure everything and recheck engagement pattern.

I have not had that specific traction lock (I'm very fond of the OEM unit), so I could not tell you what is normal noise for those things.

You should change your thread title to include the words, "Yukon Traction Lock".

You might also be interested in these reviews: https://www.americanmuscle.com/yukon-31spline-88-posi.html
 
so on a jack both will turn together? I am use to seeing one turn one way and one turn another but I have never done that on this car. Maybe my popping noise is not inthis and is in the shocks I also changed the upper and lower control arms

That's because you are used to an open differential and not a positive traction diff.

The faster one wheel turns ahead of another, the tighter the clamping force on the clutch packs. That's what those extra spider gears are for.
 
I don't think it is a Yukon it just looks like one. I am not sure what this rear end came out of. I am thinking it came from a 87 mustang. I am going to check the shocks to see if that's the noise I am hearing and feeling. all of them are the original I will let you know what I find. I am now thinking the diff is ok. Like I said all I did was change the ring and pinion gear, did not have this issue before. Shocks locked up when car was up in the air so that maybe it.
Thank you for the break down of this unit.

Any way to tell what this rear end came out of?
 
With a positive traction rearend both axles will always stay engaged together unless it is slap worn out or broken. The rearend that you have may be from a Mustang but it didn't come down the assembly line with that differential in it. You are looking at an aftermarket Yukon differential.

Take a real close look at your upper & lower control arms. They can bind and cause popping noises. Bolts should not be tightened until is fully weighted on the ground.

What upper / lower control arms did you use? Rubber bushings or poly?