I have a S4 welded(dumb) T2 LSD diff that has been recently making some popping noises when turning at slow speeds, especially backing up. It started to get worse, to the point when I punch the gas a bit i'll hear a clank too. I'm about to dive my car from south FL to AZ so I figured I'd check it out.

When I jacked it up the first thing I did was grab the driveshaft and move it back and forth a bit. I noticed the stub shafts going into the diff have play. Driver side wasn't too bad put passenger was bad. I also noticed if I pushed in the driver side the passenger side would push out and vise versa. Is that normal?

Anyway, just wanted to see if anyone has any ideas. I was suppose to leave for AZ today but instead I'll be dropping my subframe and tearing my diff apart again. Thanks for any help!

 

When I move the drive shaft, the play I'm talking about is up and down, meant to specify that, can also move it up and down with my hand.

 

When you say drive shaft do you mean half shaft? If so it sounds like you have a worn out cv joint.
With a welded diff you may be one wheel drive and don't know it!

 

Okay, I tore it apart and there was a TON of play in the whole assembly once I opened it up. As far as I could tell, the bearings were shot. I replaced them and put it all back together and no more play.

I didn't have the tools to set backlash so I read up on it and set it the best I could without the tools. I made it tight enough that I could barely turn it, then slowly loosened it until it spun freely.

Got everything back together and put the subframe back in by myself which was a nightmare. Go to pull out of my driveway and "POP"..... Fuckkkkkk.

All the play in the stubshafts is gone. Only thing I can figure is there is too much backlash which is causing the ring gear to smack the pinion gear when the inner wheel skips due to the welded diff. I jacked the car back up and when I turn the back wheel there is quite a bit of play before I hear it hit the pinion gear which I don't understand. So, I really don't know what to do at this point, I'm suppose to leave tomorrow to drive 33 hours to Arizona in this thing. Guess I'll just have to cross my fingers!

 

I would feel sorry for ya but welding an Lsd?..why?,and on a street car?
Make sure the Guy in the Tow truck uses deodorant.I have the feeling you are not gonna get far. ..(your not fully clean unless your Zestfully clean...good song..!)

 

Thanks for your helpful contribution misterstyx. The car is being built as a track car, however I had to sell my daily so now I'm driving it daily. I had no choice but to weld it, it's a long story that I don't need to tell you. If you know how a clutch type lsd works then you know it's really no different then welding an open diff. So please go be useless somewhere else.

Anyways, I've come to the conclusion that the sound is not the differential. I believe it is the rear diff bushings. The ones that the studs on the car go through. They are torn pretty bad on each side and I believe it is allowing the diff to have little a bit of movement and it's hitting the bottom of the car. A lot like when the front mount goes out but the sound comes from further back and on each side of the car.

 

Do you care to explain why the only choice you had was to weld your clutch type? It just might help us understand the situation a bit better.

The thing is, that I can't really think of a situation (other than a drag strip) where a locked differential would be more beneficial than a clutch type LSD. Drifting... sure a welded would come in handy if all you had was an open differential... But a lot of people who regularly attend drift events actually seek out the s4 turbo LSDs.

I had a welded in my car. For a short period of time. Couldn't stand it. I had those same noises, even with a solid boxed front diff mount, derlin rear diff mounts, and a pinion snubber. Its a solid differential: they just make a **** ton of noise. Found the same diff you have (but not welded of course) and have been happy with it ever since. I would personally just try to find another s4 turbo lsd if I were you.

BUT if you don't wanna do that... reinforce the **** out of everything. And make sure your backlash is set right. Install a pinion snubber with a ton of preload. Check to make sure your mounts are in good shape or solid or whatever your budget allows. But you can really expect it to be a bit noisy either way.