Strange noise from rear end/somewhere - throttle sensitive
 

So here's the deal...

I installed my welded differential about a month or two ago. Since then, there have been no problems with the car through drift events and daily driving until recently. A few weeks ago during mid-drift, the car kind of just cut off and it almost felt like an axle or my differential just wasn't allowing the wheels to spin anymore. Started the car right back up, started sliding again, and all seemed normal except for this LOUD annoying noise.

The noise seems to be coming from somewhere in the back of the car. It sounds like its around where the driveshaft meets the diff, the diff, and the axles. The noise begins around 35 mph and increases in noise level with increased speed. The weird thing is that the noise ONLY is heard when I apply ANY pressure at all to the accelerator pedal. No matter the speed, the noise is not heard if my foot is not on the pedal. Its a strange and loud noise, so I want to get rid of it!!!!!!!

ps I just replaced one of the axles that I thought was messed up, but it didn't change any bit of the noise. I suppose I'll replace the other axle and the driveshaft seeing as I happen to have extras.


Any ideas? Help please!

Check for anything loose between the drive shaft and diff.
Kinda sounds like there is play between the two.

check the u joints

Hate to bring this back from the dead, but we are experiencing this same issue on my girlfriends FC. Just installed coilovers, all was well for 2 days, now we have this same issue.

Anyone have any insight to this?

Another bump. Just swapped my rearend and this one is doing the exact samething as the OP. Has anyone figured this out? Everything is tight and the diff has fresh fluid.

OPs issue is either a broken diff mount or a chunk of slag came off his shitty welded diff and took a chunk out of the R+P and the diff is getting eaten away.

other 2, check your diff mounts, a bad u-joint can cause a similar issue. remove the driveshaft if the mount is ok and try to twist the yokes, if they bind then you need new joints.

PS: if you weld your diff, good luck getting any real technical help. easiest check is to drain the diff oil and check for chunky diarrhea.

this sounds like diff bearings are going, and/or the ring and pinion gear are not happy with each other anymore.

you would have to pull out the diff and check it for gear teeth missing, wear pattern on the ring and pinion gear, and backlash, etc....

is it like a whining noise? if so I think you may need a Diff, every car I have worked on that has a whining noise that is accelerator dependent has been a diff that was toast

Just swell. I swapped a REALLY loud lsd rearend (sounded like a jet engine the entire time) for a open diff rear that makes a scratching noise from the front pinion bearing, confirmed today. Ugh. How much would a shop charge to rebuild my old one? Buying all the parts myself seems like its going to cost me $350 and thats without rebuilding the lsd. My front end is pretty fresh, id like to get the rear fresh as well now.

a scratching noise like a hamster running a squeaky wheel? that is a bad u-joint.

differentials growl when they go bad, like Cujo.

I have 2 extra driveshafts, worth a shot but this driveshaft was fine before the diff swap. Eh ill check it out sometime this week.