Rear end clunk (More than the usual sound thread)

[Tristan Barton]

So the issue I'm having with my 240 is that whenever Im taking turns/bumps, off the gas, or chugging along with my welded diff there's a crazy heavy duty rattle from the rear end, and everything seems tightened down. When it should be just chugging and the outside/inside tire is slipping it should drive smooth still but instead there's vibration in the transmission and something must be getting out of alignment because I can't shift without it grinding when that's happening. Driving straight I shift fine. Any ideas?

The car feels extremely loose in the rear like there's slack when the driveline isn't under load.

Basically the car is driving terrible and I can't figure out what's causing it.

It's more than just the sound of having a welded diff.

[jr_ss]

Jack it up and start shaking things with your hands.

[Tristan Barton]

I did, that's why I said everything seems tight. The only thing that had some movement was my exhaust but it cleared everything. Still trying to figure it out.

[mechanicalmoron]

Subframe bushings?

They don't account for the grinding of gears, but if you take a turn while laying on the gas, they can make it feel like your car is being repeatedly slammed very hard.... mine does it a bit from one side, but I have an open diff, I can imagine it being horrible with a welded one.

If you have blown shocks and/or stock springs, it can feel really lose and rock/buck around, and if you have that AND bad subframe bushings, it can set up really nasty resonances in the thumping, making it literally scary.

It can also, when it's not doing horrible things to handling, cause a rattling noise from outside, and/or a thumping inside.

[Tempo]

I get a constant thumping noise while driving my car in a straight line thumps increase as speeds increase. I took off rear subframe and re tightened everything this time with an impact gun, still have thumps. I'm sure the thumps are being caused from one axle on the driver side due to the circular part that goes into the upright being bent and flattened during a 5 lug install by a friend :banghead:

Car: s14
Mods:
Welded diff
rear subframe bushings
Pbms camber/toe arms
Spl diff bushings
Spl eccentric lockout kit
Rear alligned t o -0.5 camber 0 toe by martin at pbm

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[Tristan Barton]

Some guy told me my subframe bushings could cause it, and most likely at least one of my coilovers are blown. I can hear a faint thumping/clunking on really really mellow turns also. But hopefully solid subframe bushings will fix it all.

Also, going over speedbumps and anything like that theres a loud bang from the rear? Anyone have experience with it?