Droning noise and vibration in driveline at specific gears and rpm

[warlordcrom]

Hey, I've had this droning noise and vibration coming from what feels like the rear end ever since my SR swap, with the stock driveshaft it would be loudest in 4th gear between 65-70 km/h (40-43 mph) when decelerating in gear, but still heard very slightly in some other gears at a certain speed range. Under load, and neutral, no noise ever.

I upgraded recently to an aluminum 1 piece driveshaft, now the noise is gone in that range, but instead its there at 4th gear at 70-80 km/h (43-49 mph), 5th gear at 80-90 km/h (49-55 mph), both when decelerating and in 3rd gear at around 40-60 km/h (24-37 mph) when decelerating or even under load. The noise is now higher pitch and the vibration is at a higher frequency (probably due to the fact that its one piece with no rubber along the way like the stock one)

Sound seems like its coming from the diff.. however may be affected by gearsets in the tranny? I dont know..Has anyone come across something like this?

[Pacman]

Center carrier bearing. Put the stock, problematic driveshaft in the can and drive it. When its happening, put you hand on the backseat in the middle (where the hump is). You'll feel a vibration there and the noise is from that. Mine is doing that as well and I sourced it to the bearing. Haven't replaced it yet, I don't like working on my car (cause I work on others shit at work, damn Toyota recalls).

[warlordcrom]

I hear ya man, I work for Mitsubishi. Not a bad product to work on, but hard to stay motivated to work on your own shit after hours lol not to mention all your friends and familly that want in on free service :P We never have any differential issues so I lack the experience in that field. Do you know if the s13 diff has an adjustment to it? It will just have to be replaced I think..

[az_240]

Sure it's not the tires or wheel bearing?

Use a runout guage to check the runout on rotors and driveshaft.

[warlordcrom]

Yeah wheel bearings are good 100% as for driveshaft, I just changed driveshafts and it appears to be good. It was taken off another car which did not have that problem. I machined my rotors not too long ago as well.

[Tranman324]

So any solutions to this? have the same problem!

[supreme_1]

is your motor and trans mounted straight?

[warlordcrom]

I've looked into my issue a little while ago while my car was up in the air, using a stethoscope and another tech driving it, I sourced the noise to be coming directly from inside the rear end of the tranny. So I'm assuming it has a bad bearing. I have an extra tranny at home, so when I get a chance, I'll throw it in and see if anything changes.

As for engine and tranny alignment.. it appears to be straight, but what do you mean exactly? I think that if it were crooked though, the noise would be more consistent.

[bb4_96]

If you used your SR trans and sisn't reuse your ka trans(with sr bellhousing) when you did the swap then the trans changed with the swap and ought to be your culprit since you've ruled out most else. Most SR trans are beat to piss anyway.

[RipthatE]

yeah id deff say check drive shaft run out or rotating the drive shaft around.... if not check mounts.

[warlordcrom]

Exactly, I'm pretty sure its the trans. Again, its not mounts or driveshaft. Gonna throw in the other tranny in a few weeks when I have a moment and let you guys know the outcome.