Odd sound after subframe riser installation

[polar951]

Hi guys,

Ive been having a quite odd sound after installing some pbm subframe risers and also solid diff bushings and i have done a lot and alot of searching but results have been all over the place. I do know that when installing solid bushings, more sound is expected to be heard but many peoplehave had this problem.

So before i even installed my subframe bushings i had no "whine" or "slight grind"d sound whilew my clutch is engaged and is on acceleration. However, after installing subframe risers and also solid diff ear bushings I have gotten a rather annoying sound which i believe is most likely related with my drivetrain but i am still not quite sure. I've searched zilvia and people have different responses for my type of problem (some say its TOB, some say its input shaft seal, pinion bearing going out, or driveshaft carrier bearing or ujoint, exhaust leak).


I'm fairly certain that it would have to do with the drivetrain, but i cant really pinpoint what it colud be when there was so many different possibilities and its quite bothersome because ive never had this sound before these bushings and a majority of the people that i know who have the same mod, dont have this whining sound.. When i do clutch in while crusing on the freeway, the whining noise goes away which is also odd so i feel like it cant be wheel bearings, or rotors rubbing or driveshaft rubbing/carrier bearing etc.

My dad whoms a mechanic says its the ring and pinion going out int he differential but i wanted to get some more input. Thanks

Any input?

[DJ-of-E]

Did you replace the rubber subframe bushings with solid aluminum? Did you replace your driveshaft with a 1 piece?

The rubber bushings pretty much absorbed that whine/vibration. But if you replace with solid, you would definitely hear the drivetrain noise.

[polar951]

Yes, i had replaced the differntial bushings with aluminum ones but i did not replace my driveshaft with a one piece. It's really puzzling because a couple of people I know dont have this problem with the same mods, so im very puzzled....

[di-devol]

It's just the diff making noise. Welcome to the solid bushing life.

[Def]

Yep, there's a reason the factory had soft squishy rubber bushings back there. I've been in some cars with urethane bushings that didn't have extremely noticeable diff whine in the cabin, but I guess there's still a hint of it. Solid bushings make the rear of the chassis just reverberate with the diff pinion/ring meshing.

[ChoeBoy]

Yep. I did the same mods recently Polar. Can confirm there's an increase of noise from differential.

[e1_griego]

How much interior do you have?

My car is all solid and I don't really have any whining issues, but it's full interior, and a coupe.

I will vouch that Def's hatch is loud as hell all stripped out and our cars have the same full spherical setup.

[Def]

Yep, and I've gone straight from "quiet diff with rubber subframe bushings" to loud as hell with the solid bushings. Full interior with the tar on the chassis will definitely quiet it down some. As without any of that stuff the whole rear chassis acts like a big speaker, amplifying the diff noise in the car.