humming diff problem

[nissan_star]

Hi, I just installed a used jdm 180sx diff, said to have around 45000miles on it. I drained the old oil and added Royal Purple Max gear 75w-90 with lsd additive. I have since, heard a whining and humming noise that increases with rpms, but only happens when i accelerate.

Is this the gear oil I picked? Or do I have a bigger problem?

[OutToWinPAHC]

Well LSD additive in a VLSD is pointless. Humming usually comes with heat and wear, could it be leaking. Is it low?

I would inspect it, drain and refill to see if it helps. Try some heavier gear oil like Lucas 85/140 no LSD additive. Its a sealed unit, not a clutch type.

[nissan_star]

It isn't leaking, I filled it to the filler plug. I might inspect it, but i really think that its the oil weight. even the r200 and 200v take 80w-90 oil. since this isn't a r200 or 200v i didn't know what oil to use.

I was going to use redline, any other oil sugestions? lucas is good too?

[OutToWinPAHC]

Its a R200V.

[AZ89two4Tsx]

Are you sure it's not the u-joints in the driveshaft?

[HoosierSX]

my 1st vlsd hummed till it went kaboom.... ended up being broken teeth on the pinion gear. so good luck with that

[blacksrjdm]

Had the same problem, the backlash is out on the ring and pinion mesh. Take it to a reputable shop and ask them to reset the backlash on the diff. Might cost you a few bucks, but, can be done. I had mine reset after installing Kaaz diff because I heard similar whining.

If not that then it is the bearings.

[nissan_star]

i was under the impression it was a r160 or something, I can't find my original source or that info .

I will change the oil first, 80W-90, then listen for noises. I know the fluid I put in it is to light and heavier fluid will help get rid of the noise. (I don't know if that is the cause for noise and if it just masks it will I be in trouble?)

If it doesn't rid the noise, then I open the pumkin. Maybe there will be a suprise in it, like an OS Giken 2 way clutch type lsd

[Razi]

Or a broken vlsd. :P

[moulton712]

sometimes people install s15 helical diffs into 180sx's and then sell the diff and they forget to mention that. the s15 diff will hum or whine.

i donno if this is your case

[LOLChevyPower]

It's prolly worn some. Put new fluid in it, see what happens. Pull the back of the pumpkin off and have a peek inside, give it a bit of an inspection. its pretty easy.

[blacksrjdm]

sometimes people install s15 helical diffs into 180sx's and then sell the diff and they forget to mention that. the s15 diff will hum or whine.

i donno if this is your case

Why would the diff whine with a helical LSD??

[lilpiton]

Why would the diff whine with a helical LSD??

sometimes people install s15 helical diffs into 180sx's and then sell the diff and they forget to mention that. the s15 diff will hum or whine.

i donno if this is your case

So I installed a S15 HLSD in to my 92 hatch and it does whine! What is the case in that??When i drive and im like in 5 and im down shift to 3rd lets say and it will whine under deaccelleration, but not everytime, Then when i press the clutch in the noice goes away?
Modified by lilpiton at 1:12 PM 6/22/2009

[blacksrjdm]

I would say that none of them should whine if set up properly. If you have a whine of sorts, it normally means that there is something wrong. The backlash is normally the culprit, and will eventually blow the ring and pinion, as I did.

[nissan_star]

I have installed the spl alum. subframe spacers aswell. Those are said to add to diff/drivetrain noise. I also have no back seats, I can hear this coming directly from the diff area. I checked my U-joint when I took off my driveshaft, no rust no nothing, aok.

what if question: What if I change the fluid and no longer hear the noise? Does this mean I am safe?

[gumby74]

I have been running an S15 helical for over 2 years now. Assembled the housing myself and had the backlash and mesh inspected before install. Everything was good to go. I also noticed some humming at slower speeds. I replaced my driveshaft with a 1piece aluminum shaft and the humming has all but dissapeared. I also am running aluminum subframe collars, heim joints at all rear links and recent urethane bushings every where else. If the humming is still there it is very subdued or I simply am used to it already.

[Fr0zEn]

How would the car act if the diff is about to break?

Would it cause the car to not go above 2nd gear?

Would it make a grinding sound from the rear when shifting?

[nissan_star]

My noise doesnt sound detrimental to the diff. After I installed it I actually noticed much smoother operation of the drivetrain. I guess that is the new diff fluid, even though it is too light. The other fluid has probably never been changed.

I should have it out and refiled by wed. If it still sounds bad... then I get serious

[lilpiton]

Or could it be the LSD bearings?my pinion seamed to spin a lil hard but i thought since it was like this before on the open diff i didnt take it apart.My buddy checked the backlash for me, he just took that class at UTI, and he said its good..

[nissan_star]

g0d d^mnit. Changed the oil. No difference in noise. I will call a shop and try to see how much to reset backlash or w/e it needs. If it is more then $100 then I will just buy a j30 diff.