Blown axle or LSD???

So, something went bang yesterday when I launched on my final run of the day. I chalked it up to things possibly moving around despite the mounts (CS TMM insert, DM PMM, CPE Stg 2 RMM). I completed the run about .5 second off my previous runs so nothing was obviously afoul. It drove the 35 miles home from w/o issue or weird noises I typically associate with blown CVs or Birfields.

Fast forward to when I was rotating tires and found the L/H inner CV appeared to puke some grease on the lower control arm and inside of the wheel. Upon closer examination no cuts or tears in the CV boot so it's a mystery. It gets better. While I had the left side in the air and right on the ground I could freely spin the tire as if there was no diff or the right side was in the air. This is when I got the sinking feeling of an axle swap or worse blown LSD.

This evening I got the front up on jacks, no diff action, rotating either side does not move the opposite side at all. There doesn't seem to be any axial or radial play in the CVs. Started the car put in 1st and let it idle, I can easily hold either side, the LSD does seem to try and limit the slip but it's fairly easily overcome and can hold the tire from rotating. I had read on elsewhere that checking this type LSD operation on jack stands is not really the best indicator whether it's functioning. I didn't have a chance to drain the fluid tonight, tomorrow.

So the long and the short of it is, is there an easy means of confirming whether it's an axle or something internal to the tranny/diff? I realize the grease paints a picture but the joints feel solid when manhandling them.

TL DR Something went bang, need a little help narrowing down best way to confirm the culprit without mass disassembly.

 

Maybe just pull the parking brake and do a burn out while someone films. If both tires are smoking the lsd is working.

As for the axle, make sure you are pulling on the boot a bit. Sometimes boot splits are rather small and hard to find until you push&pull on the boot itself.

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Before I drain the trans I'll have to try the wet grass trick, I don't wish to cause any more damage than I've already done.

I massaged both inner boots and no holes or leaks noted. The outer boots are made of some stiffer plastic that can't be manipulated much.

 

I dont really think there's been any notable lsd failures. I'd check the axles.

 

There has now.....

 

I had a few mins last night and drained out part if the trans, no bits, a good sign.

I reinspected the inner boot, stretching and pulling to see if there are any holes. I did end up finding a small hole I could squeeze grease out of. Since the puking grease started post bang and I haven't hit anything I'm guessing the mass migration of parts likely pierced the boot. Fingers crossed....new axle ordered. More to come if/when I get it apart and confirm.

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Well, not encouraging findings.

Pulled the axle and no apparent damage other than the hole in the boot. Drained the rest of the fluid, no chunks. With the axle removed and the wife turning the opposite tire the splines appear to turn the opposite direction than she was turning like a normal open diff. While she continued turning the opposite tire I was able to stop the splines from turning with just my finger (slight drag but easy to stop).

So, it appears this is now diff/LSD related. For the folks that drag race or autocross and have had their trans apart does this look as bad as it seems...LSD replacement?

I'm not sure who to tag but I sure would appreciate it if folks could tag the right guys. @Raider, Eric any thoughts?

 

The shop manuals are available here for metal members. I'd check those out. I think Tomas on MSF has replaced his differential, but I'm not sure.
[doublepost=1501293594][/doublepost]@my2k13speed3

 

I've got all the manuals as well so if it comes to that I should be in good shape. Since it still capable of moving on its own I stabbed the axle and put it back together for now. I'll peruse the other site and see if I can find Tomas' post.

For gee whiz I reached out to GKN UK yesterday, no luck there because they're all on holiday for August already. I found a GKN Driveline location in the US but have only been getting recordings and zero call backs. If/when I get any decent info from GKN I'll be sure to share.