just installed MFactory LSD; now I hear some grinding-like noise when turning hard

I hear this noise when the steering wheel is turned all the way left (or mostly there) and I accelerate, from a stand still, with half decent throttle.

This noise started after I had the MFactory LSD put in. I also had the rear engine mount replaced (with a stock one), but I don't think this is related.

The sound I hear isn't exactly what I'd label as a grinding noise, as it is of lower frequency, but it's the best description I can come up with.

I'm trying to figure out if this noise is coming from the MFactory LSD, or something else?

Any MFactory LSD owners out there experiencing anything similar?

nope, no werid noises from mine... Did you put in new bearings and races while you was in it? Did you loctite the bolts in?

I had a mechanic put in the diff. He replaced several MSP diffs not so long ago, and seemed like very knowledgeable guy so I used him for the job.

He replaced bearings and races, and all the other hardware that normally needs to be replaced.

He torqued the bolts to ~83 lb (he said that 75 didn't seem like it was tight enough). He put loctite on the bolts like I told him to. He also put loctite on the ring gear where it comes with contact with the diff. He said that he didn't like how once the bolts were (without the nuts) in, the ring gear had a bit of lateral play. MFactory told him that their ring gear has some play too, but that it's OK. He put loctite on the ring-gear because he wasn't comfortable with that answer.

pomidor said:

I had a mechanic put in the diff. He replaced several MSP diffs not so long ago, and seemed like very knowledgeable guy so I used him for the job.

He replaced bearings and races, and all the other hardware that normally needs to be replaced.

He torqued the bolts to ~83 lb (he said that 75 didn't seem like it was tight enough). He put loctite on the bolts like I told him to. He also put loctite on the ring gear where it comes with contact with the diff. He said that he didn't like how once the bolts were (without the nuts) in, the ring gear had a bit of lateral play. MFactory told him that their ring gear has some play too, but that it's OK. He put loctite on the ring-gear because he wasn't comfortable with that answer.

Click to expand...

wait are you saying the ring gear that bolts into the mfactory diff had a little bit of play in it.. IE you can wiggle it while its attached to the diff?

yes, but only when the bolts weren't tightened with the nuts. He said that he could wiggle it a little bit to one side or the other (clock and counter-clock wise - if looking at the ring gear as if it is a clock). Mind you, once he put and tightened the nuts on the bolts, the wiggle was gone.

i thought you were saying there was play with the bolts tightened. that would of been scary. another thing to check is if the axles are fully inserted? does it sound like a whine?

No, I don't think I'd call it a whine. I'd think of a 'whine' as the noise you sometimes hear coming out of your car speakers. An alternator whine that is. The sound I hear is more like metal rubbing against metal. Imagine you grip a stripped bolt with pliers, to loosen the bolt. You turn the pliers but the bolt doesn't move. It only skips inside the pliers, while giving off a low frequency rumble as the shallow teeth of the pliers skip over whatever rounded edges are left on the bolt.

They say a picture paints a thousand words...

...I wish I had a sound clip of that sound, that I could post. I could try recording the sound, but I have a feeling that with the engine and exhaust noise in the background, it wouldn't be audible enough. I might give it a try though.

I saw my mechanic today to have him investigate the noise, but I couldn't reproduce it because it was raining. I need good tire grip to get the throttle and the wheel angle just right to reproduce the noise. He tried to reproduce it too, but with wet pavement it was of no use. I've described the noise to him. He's installed these types of diffs before and expects for it not to be as silent as the stock MSP diff at certain conditions given its design, but he said he can't tell me that for sure until he hears the noise himself. I'm due to drop by his shop again when it's dry.

Our LSD doesn't use nuts, as the bolts thread in to LSD flange (which are threaded on our LSD) and shouldn't be any play whatsoever once tightened. If there is play, your ring gear is past its sell by date.

As it is a Helical LSD (i.e Gear Type), it is silent during operation. You should not hear any whine, crunch or chatter coming from the differential area.

Are you sure your mechanic actually installed your MFactory LSD that you gave him?

Hmmmmm...

MFactory said:

Our LSD doesn't use nuts, as the bolts thread in to LSD flange (which are threaded on our LSD) and shouldn't be any play whatsoever once tightened. If there is play, your ring gear is past its sell by date.

As it is a Helical LSD (i.e Gear Type), it is silent during operation. You should not hear any whine, crunch or chatter coming from the differential area.

Are you sure your mechanic actually installed your MFactory LSD that you gave him?

Click to expand...

Forget about the nuts. My bad. I've assumed it was a nut and bolt configuration. I haven't seen the LSD in person (it was delivered to the mechanic). When he spoke of tightening the bolts, I assumed he was tightening them to the nuts. I see what you mean. No nuts. Bolts tighten to the LSD flange. My apologies for the confusion.

And no, there was no play after the bolts were tightened. There was play only there when they weren't tightened yet.

I do hear a whine when I'm in gear and with foot on the throttle. It increases with loudness as the speed of the car increases. The whine will stop if I let my foot of the gas. I can't say what is causing the whine or when exactly I started hearing it, so I'm not blaming the LSD. It's a bit irritating, but it's not that loud so I'm not bothered by it.

That grinding-like sound *is* there when I accelerate while turning, from a stand-still. It started after the LSD was installed. I have to be turning with just the right angle and just the right amount of throttle to reproduce it. I still haven't figured out how to reproduce it on demand. I just hear it every now and then when I drive around daily.

i know the exact whine you are talking about, although mine doesnt happen while driving so i am not concerned about it. my diff/clutch only makes a "whine" noise when engaging the clutch while on throttle. speaking of which, what clutch do you have in your car. mine didn't make noise for the first 1000 miles or so but once the clutch was broken in the "whine" started so it could be clutch noise as well. though i think yours may be your diff because you say it gets worse as speed increases whereas mine is only when engaging the clutch.

I bet your mechanic did something wrong. I have a Mfactory LSD and it is 100 percent like the stock. In every way as far as DD is concerned. Im telling you right now I dont know how he torqued the bolts any more than 75 ft pounds. I torqued mine and it was all we could do to hold the ring gear from spinning. I actually took a 10,000 pound ratchet strap and some 2x4's and had to come up with a crazy way of holding it. I ended up being able to use the hitch of my dads 3500 dodge in a weird combination non describable on the internet. Also two of my brothers also holding the LSD and got them to torque down. I honestly dont know how you could torque them any tighter.

I would say take it back to the mechanic and tell him whats wrong.