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Discussion Starter #1 (Edited by Moderator)
Gustav addition in green below: Official reply from Dinan:

Answer from Steve D:
  • shipping ten per week
  • Noise is attributed to: (1) BMW gears and (2) not following BMW install procedure in TIS
  • "In addition we have seen the rear cover hit both the stock gears and Dinan gears. Dinan gears are larger, so ours hits worse than stock. We are now including clearanced rear covers with the diff."
  • "We got a cover with each of the 50 differential cores we purchased from BMW. They are already clearanced and on the shelf."
  • "...we have been using he same ring and pinion in the E46 M3 for 5 years."
The following is Steve Dinan's official response to Gustav
(I'm posting for Gustav because he's traveling in Germany at the moment)

Steve Dinan said:
It looks like a further explanation is in order. TIS instructions and photos inserted.

I was asked to explain what we know about the situation on noisy E60 M5 differentials and that is what I did. Based on comments I feel further explanation is necessary.

We use both BMW gears and Dinan gears depending on availability. All of the ones that we have received back for noise so far have been BMW gears. That does not mean that BMW gears are no good it also doesn't mean that we will not get Dinan gears back with the same problem, it just means that all of the ones we have gotten back so far have been BMW gears. I have heard of an install causing a whine and BMW has a procedure with a warning on it (see BMW instructions below) that says that it might make noise if done incorrectly. We assume if BMW warns against this that they likely have a good reason. I have never had a clearance issue on an M3 rear cover either. The rear cover on the M5 is slightly revised by BMW from the M3 cover (see photos). The recess for the ring gear is smaller on the new M5 and M6 than it was on the M3 and the lip at the bottom of the recess is protruding more. It was pointed out by one of our dealers that this cover is very close and in some instances hits. When reviewing covers, we saw some witness marks on the covers from the stock gears. Our conclusion is that BMW cut it a little close. These are sand castings and as such are not very consistent parts.

There of course could be other causes for the noise as well but I do not know of any so I can't report them. These are just what our investigation has turned up.

Some people have posted that they are not sure if they hear anything or the noise is very small. As I stated before most of the gears are fine out of those delivered on the M5 and hundreds on the M3 we have had 13 warranty claims related to this issue, 5 are currently open. I think if there was a problem with Dinan gears, BMW gears, or our procedure, it would have come up years ago. It could just be that we got a bad batch of gears from BMW. Of the many 3:91 sets we sold in the last six months a small number were BMW gears, so not all of those have bean bad either. Every unit that has been returned has been inspected, a tooth pattern run and back lash checked. No assembly error has been found. I personally have inspected each one.

There were some concerns posted about warranty. The differentials have been and are still being replaced, parts and labor at our expense. It is always a complete unit and the new diff will come with a modified cover. The warranty applies to all Dinan differentials whether they have BMW or Dinan ring and pinions inside them. We treat them the same.

There were some concerns posted about catastrophic failure. In my experience a small whine does not result in a catastrophic failure.




just got a call back from dinan, so he tells me that he's having a meeting with technichal to adress the issues !! i didnt tell him i was a board member but he told me that there are a lot of the diffs coming back for the whining noise and when they open them all the gears are perfect,and how he thinks that the driveshafts are not being installed correctly or the bearing are not being repacked properly.he also said this was the problem with the e39's diff's when they were hot..i said so what about the one i blew up he said they just can't wait to get it back to see what the hell happened..

this was what i posted yesterday, well this morning i got a call from louise he says mr neil i have good news !! we had a meeting with tech and we think we have found out why the rear diffs are having problems !! thats great i say,what do you think it is,well apparently when installing the diff the dealer is supposed to just use the stock cover that works on the stock diff,but with the larger gears the pinion(gears) are touching/rubbing the top of the cover,causing a whine and also causing metal shavings to fall in to the diff..from now on they will send a modified cover for the diff along with the core..he was very optimistic that this was the problem..i should have a new diff and cover in about 2-3 weeks..he said to keep using this diff until then..

for anyone who is thinking/getting/ordering a diff i'd wait a couple of weeks till they can get a bunch of these covers and modify them so you don't have any complaints..ANDREW THIS MEANS YOU BUDDY !!

allow me to say this:througout all this dinan has been right there in contact with me keeping me informed on everything thats happening, im very impresssed with their service and customer service..the even called me before calling the dealer..i now know why they are a little pricier, you know what IMHO its well worth it..:applause:

again i asked about break in !!

THERE IS NO BREAK IN,JUST ABOUT 10 MILES(WHICH THE DEALER DOES AFTER INSTALL) TO GET THE FLUID AND SEALS ALL LUBED UP.. IF THE GEARS TURN, THEN THEY ARE IN LINE SO YOU REALLY DON'T HAVE TO BREAK IT IN !! 2ND TIME I ASKED HIM
 

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Thank you.....

Fascinating. Thanks for being so persistent about this.

Dan :checkeredflag:
 

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Thanks for the information, LI. I wonder whether Dinan intends to send the new covers to all who already have the diffs installed, or whether we need to request them.
 

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Great news Neil. So what's the deal with the ones who already have the diff installed. and have the whine also? Did they specify they will put the new cover on the existing customer's diff's? Mine still whines slightly.. :confused2
 

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Discussion Starter #6
MRichmond said:
Thanks for the information, LI. I wonder whether Dinan intends to send the new covers to all who already have the diffs installed, or whether we need to request them.
nope !! if the diff is making noise its certainly rubbing, its causing metal shaving to fall in to the gears,you'd want them to replace the entire diff..which from what i got they have no problems doing so..
 

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This is interesting. Probably means we all have a problem. Thanks
for the information!

If the gears were touching at all then it would indicate that some damage
has probably occured. I called Dinan but unfortunately had to leave a
message for Louis. I suspect he's probably got about 50 messages about
now. Seems to me that they need to replace the whole diff for everyone.
 

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Humm. Mine doesn't wine...yet. I wonder if I should have it looked at. I'll wait untill you get the new one in and report the status.
 

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I left a message and I'm waiting to hear back from them this morning.
What I find strange is that not everybody is having this problem. If the
gears are too big then everyone must have this problem.
I believe I had a little bit of the whining at the start but I don't notice
anything now except the added power. Does this mean the gears grinded
down to a point where it's not rubbing anymore? Is there some kind of variable
that some installers know about that others do not? I have an M6...does
this make any difference? These are the questions I'd like to have
answered. I don't want to be stranded anywhere because of the looming
timebomb that is the differential.
 

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I plan to sit on the sidelines and see what happens. I have no whining and, emboldened by the "Break-in? We don't need no stinkin' break-in" edict from Dinan, I mashed the gas in fourth gear (intentionally in a higher gear than I may have used otherwise) entering the highway this morning. The added torque from the diff is really remarkable. I highly, highly recommend this mod.
 

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///Marshall said:
What I find strange is that not everybody is having this problem. If the gears are too big then everyone must have this problem.
I tend to agree although I assume the diff housing and cover are cast items that for the outer dimensions would have much less strict tolerances than the gears themselves.
 

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Well. I had my 3rd dif put in today and the problem IS NOT coming from the cover. Before installing the dif, we looked at the cover and yes there is some major rubbing with it so we took a grinder to that area and made plenty of room for the next dif to be installed. (BTW, the rubbing is coming from on top of the gear and nowhere near the teeth) After the tech saw this, he basically said, "yeah that is a problem but that is not causing the whinning noises". So after install, we took the beast out for a spin and this dif is worse than the previous two:mad: . After the ride I got on the phone with Dinan (Louise) and told him what happened and he did not sound surprised and later said that they know about the cover problem but do not think it is the cause of the noise. He then said that after talking to numerous customers and techs that they think it is an install problem ( I guess they had the same problem with the 7 series). ARGHHH!!!

BTW, who ever had the 3.91 dif installed, you have some metal floating around in your rear end.


Cheers ///
 

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I've had my second diff for about two months. The first was like the others..whinng like a mad dog...the second seems great no noise at all..I'm due to have the diff oil changed next week, I'll inspect for shavings and report back.
 

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As you all know, the M differentials need an oil change after the first 2000 km's.

They use special running in oil.

Have seen a diff on an M-coupe that ran 18000km on the run-in diff fluid and that diff was scrapped.

Does Dinan issue the same procedure?

Wout
 

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Discussion Starter #17
dealer is taking my car on tues to kind of undo everything on the install while over the phone with dinans tech and go over the install to ensure that the diff is being installed properly or not..but if that was the case then all of our dealers across the country are doing it wrong,ill report after i hear any news..
 

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Not wanting to jinx myself, but no whining whatsoever from the get-go. I had one of the first Dinan diff's installed on October 10 at 30,380 miles, and followed break-in to the letter, including the change in differential fluid. Now, almost 10,000 miles later and still no problems.

I'm concerned though, and hope to hear from Dinan what the source of the problem is, and whether or not a recall is in order.
 

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To add to the confusion: I had an obvious whine when the diff was first installed.....800 miles later, I can just barely hear it, in silent running mode (no radio, etc.). So it was bad, and is getting better with every mile....

ouich


Tom
 
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