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      04-23-2014, 10:52 PM   #1
mfanatic325
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Performance Gearing Differential Replacement

Just thought I'd share...
So as some of you may know, I've been having ticking noises coming from my differential for the past year or two, developed from track use. Some research into the factory M-variable diff shed some light on the matter. I used to think it was simply grime on my lug nuts, or other non-issues. However, after getting several opinions from different trusted mechanics, all eyes are pointing at my LSD (probably overheated).

In any case, to save myself time and money overall, I decided to just get a whole new built unit and simply have the old swapped out with the new. It would take longer and cost more to dissect the diff and figure out exactly which parts I needed and which parts I didn't. Since I wanted as little downtime as possible on the car, I went with the whole unit replacement.

I decided to go with Jim Blanton's solution @ Performance Gearing (http://www.performancegearing.com/function.php) because I was thoroughly impressed with Jim's attitude. He has always been patient with me and provided me with ample personal feedback and recommendations for my particular setup. He has been honest and top notch at communications throughout the whole process, even though I stated no particular referrals from the beginning; I was merely a stranger! As some of you may also know, I'm big on customer service (especially after having a horrible experience with VF-Engineering and trying to get them to help my supercharger kit run smoothly). I give Jim Blanton and his shop full marks and definitely recommend it for those that are considering diff builds/replacements in the future.

Jim has been building salisbury-style (friction disks/mechanical ramping configuration; with both static and dynamic locking) differentials for decades and I can tell that he's extremely anal about his builds because he refuses to sell units separately. I originally inquired about potential purchase of their proprietary LSD only. He told me that he only sells fully-built units to customers because he simply does not trust other differential builders. He does not want to warrant his products for the typical 3 years/unlimited mileage if someone else does the build (where he can't ensure quality, care, and expertise during the build process).

He's building my diff, and it will be shipped out end of this week. He hasn't even collected payment yet! That's trust and dedication right there
In total, I'm paying about $3k (with core deposit) for a full housing with his proprietary LSD, the street/track setup with 40% static lock and 30/50 ramp angles for dynamic lock; as well as slightly downgrading back to the factory 3.62 final drive ratio as compared to my current 3.91

Jim says that practically any mechanic can swap whole housings, so I got a quote from the shop that usually lets me borrow their lifts and wrench on stuff that I know how to do myself. It'll be $400 for the swap labor as the job is listed at 5-6 hours of work.

Last edited by mfanatic325; 04-24-2014 at 09:21 AM..
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      04-23-2014, 11:01 PM   #2
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For what it's worth, I feel like I drive pretty smoothly. I mean, I try to push the car hard at the track, but well within my own limits; let alone the car's. Several folks local to my area have ridden with me on the track before, and I don't do anything particularly different than others in such a way as to damage the LSD. So it was a surprise to me that my LSD would crap out like this, whereas I haven't really heard or seen anyone on these forums with the same kinds of issues
In any case, I'm merely sharing my thumbs-up experience with Jim Blanton @ Performance Gearing, and documenting here on the forums that this is a viable option for our cars (for those that may be interested).
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      04-23-2014, 11:03 PM   #3
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Good game my friend =)
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      04-24-2014, 02:39 AM   #4
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Quote:
Originally Posted by mfanatic325 View Post
For what it's worth, I feel like I drive pretty smoothly. I mean, I try to push the car hard at the track, but well within my own limits; let alone the car's. Several folks local to my area have ridden with me on the track before, and I don't do anything particularly different than others in such a way as to damage the LSD. So it was a surprise to me that my LSD would crap out like this, whereas I haven't really heard or seen anyone on these forums with the same kinds of issues
In any case, I'm merely sharing my thumbs-up experience with Jim Blanton @ Performance Gearing, and documenting here on the forums that this is a viable option for our cars (for those that may be interested).
Why did you choose to go back to the 3.62 gearing ?
Do you feel that the car with the 3.91 and the VF engineering is not suitable ?
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      04-24-2014, 09:07 AM   #5
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Quote:
Originally Posted by dorifto88 View Post
Good game my friend =)
Good game indeed =/
Quote:
Originally Posted by tikamak View Post
Why did you choose to go back to the 3.62 gearing ?
Do you feel that the car with the 3.91 and the VF engineering is not suitable ?
I chose to go back to the 3.62 final drive ratio based on a few things:
1) Jim Blanton actually recommended it, saying that it was one of BMW's better decisions in terms of gearing
2) I miss staying in gear for a longer amount of time; with the charger, each gear goes by real quick
3) I primarily only go to Laguna Seca, and for me personally, I can benefit from not having to shift so much at this particular track.
4) I secretly wanted to save some money

Last edited by mfanatic325; 04-24-2014 at 09:23 AM..
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      04-24-2014, 09:11 AM   #6
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Good information all around. Thanks for sharing!
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      04-24-2014, 01:29 PM   #7
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I wish more people would take the extra time to push something like these posts out for those of the folks that do a good job. There are still a lot of them out there but for the most part you never hear about them because everyone is too busy bashing on the one bad experience they had from months ago. It's really a pleasure to read about the great services others provide and what any given persons experience was with a specialized vendor. I'm not even close to buying something like this for my car but it was still a pleasant read and a refreshing change of pace and great to know that the support is out there.

Thanks for taking the time to write this up and great information all around!

Best of luck in the swap!
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      04-24-2014, 03:06 PM   #8
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Quote:
Originally Posted by Walkurie View Post
Good information all around. Thanks for sharing!
Quote:
Originally Posted by Skiddish View Post
I wish more people would take the extra time to push something like these posts out for those of the folks that do a good job. There are still a lot of them out there but for the most part you never hear about them because everyone is too busy bashing on the one bad experience they had from months ago. It's really a pleasure to read about the great services others provide and what any given persons experience was with a specialized vendor. I'm not even close to buying something like this for my car but it was still a pleasant read and a refreshing change of pace and great to know that the support is out there.

Thanks for taking the time to write this up and great information all around!

Best of luck in the swap!
Always here for the community!
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      04-24-2014, 07:26 PM   #9
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Always here for the community!
With as much as you use this guy You'd better have grown a long mohawk by now.
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      04-24-2014, 08:49 PM   #10
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30/50 ramp angles...interesting.
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      04-24-2014, 10:01 PM   #11
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Quote:
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With as much as you use this guy You'd better have grown a long mohawk by now.
Believe it or not, I used to have punk hair when I was a toddler. My family called me firecracker head
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Originally Posted by Kgolf31 View Post
30/50 ramp angles...interesting.
Do you have a recommendation for me? Perhaps I can change it up if he's not finished building the diff yet
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      04-24-2014, 10:58 PM   #12
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Believe it or not, I used to have punk hair when I was a toddler. My family called me firecracker head
Pics or shenns
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      04-28-2014, 08:33 AM   #13
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Did you look at diffsonline.com ?
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      04-28-2014, 08:48 AM   #14
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Quote:
Originally Posted by just2talented View Post
Did you look at diffsonline.com ?
Yes sir, but if I recall correctly, they were a couple hundred bucks more expensive for a similar type of built unit. And before I could get a chance to reach out to them, Performance Gearing had already won over my business with their professionalism

Not to diss diffsonline or anything, but I highly doubt the overall transactional process could be any better. I'm not sure if the professionalism stems from the fact that these are very specific speciality items, but in any case, more vendors and shops need to have the same kind of attitude towards customer service in general. For me personally, I feel like the buyer experience has just been redefined by Jim @ Performance Gearing and I'm ecstatic about it.

For those that know me, I rarely ever dump this kind of money. I mean heck, I didn't address this diff issue for well over a year. I'm sure 85%+ of owners out there would've had it fixed long ago. I literally waited and bided all this time out of reluctance to spend money. But I truly feel like PG deserves my business, and I have yet to regret it. My diff was shipped out via FedEx last Friday from Arizona, and it should arrive at my shop by Wednesday. Perhaps I'll drop the car off this weekend to get the diff swapped out

Last edited by mfanatic325; 04-28-2014 at 09:08 AM..
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      04-28-2014, 08:59 AM   #15
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Hes doing my trans. I drove it up there a week ago, i was impressed. Brand new shop, everything very neat and organized. Dan is very professional. A little expensive but very knowledgable and patient since i had 100 questions. Not putting your guy down, just an experience from a different option.
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      04-28-2014, 09:08 AM   #16
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Quote:
Originally Posted by just2talented View Post
Hes doing my trans. I drove it up there a week ago, i was impressed. Brand new shop, everything very neat and organized. Dan is very professional. A little expensive but very knowledgable and patient since i had 100 questions. Not putting your guy down, just an experience from a different option.
I'm extremely happy to hear that you had a great experience! I second my statement about how other vendors and shops need to behave in such a way as to convince us as buyers that they deserve our business
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      04-28-2014, 09:09 AM   #17
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Are there any other places out there that specialize in gearing and rebuilds? I was only aware of diffs online until today.
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      04-28-2014, 09:12 AM   #18
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Are there any other places out there that specialize in gearing and rebuilds? I was only aware of diffs online until today.
Probably VAC motorsports, but they might contract builds out to specialists near them. I've heard of both Performance Gearing and Diffsonline prior to making my purchasing decision, but have a more fonder image of PG from years back when I was on the E46 forums and it was recommended moreso than Diffsonline.
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      05-02-2014, 09:34 AM   #19
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I went for a light drive last night with a buddy in the mountains, sort of as a farewell to my current diff
Ticking all the way! I'm surprised it hasn't completely failed yet, whatever is wrong with it.

In other news, my diff arrived this past Wednesday, and I'm going to be taking time off work next Monday to get the diffs replaced. Will report back with findings.
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      05-03-2014, 04:11 PM   #20
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Looking forward to your impressions and review
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      05-06-2014, 12:04 AM   #21
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So Jim Blanton told me that my specific build is as follows: 40/50, with 95 lbs/ft static lock (baseline, at rest rotational resistance between the rear wheels)

In any case, I got the car back earlier this evening. And although it was rush hour and I couldn't really test it out, I can say one thing for sure. It's buttery smooth, and most importantly: QUIET! I'm so glad there's no more ticking
Can't wait to get back out on the track and test out the current setup 100%!
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      05-06-2014, 01:37 AM   #22
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Quote:
Originally Posted by just2talented
Are there any other places out there that specialize in gearing and rebuilds? I was only aware of diffs online until today.
I am sure there are others that are good but diffsonline is of the highest quality I've seen . Dan built me a 3 ramp 30/60/90 2 clutch mechanical carrier with REM polished 4.10 BMW Motorsport gears setup 3 years ago . I have 15k supercharged track miles on the kit and it is flawless . I mean it puts the power down coming out of a corner like no car I've ever run . The variable lockup of the multiple ramps makes it super predictable under braking and throttle lift situations , but it still can go to 90% lockup to put my 525 hp to the ground . At any rate I can't say enough about Dan Fitzgerald , super friendly knowledgable and skilled as hell . That's why Turner motorsports and many other race teams use his diffs in their race cars . I'm glad the OP is happy with his diff but I had to give major props to Dan !
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