What Year/Model X5 rear diff is compatible with a 645 Vert??

I'm on the hunt for a rear diff and I just don't know which years of the X5 are compatible with my 2004 645 Vert. Also does a certain model have the better ratios that will improve my acceleration.


Any help will be greatly appreciated.

I would like to find that out as well. All-or-Nothing, what makes you think the X5 diff. could fit? How did you find that out? Did someone you know do it?

It was suggested in my other thread about my diff I started yesterday.

It's titled "Rear Diff Problem.....Maybe???"

Hi sometimes you can look at the ETK for the various parts numbers, but I know that the parts can be exactly the same on different models but they still assign a different part number, still worth a look????? But just realised that is not what you asked tut tut on my part!!! you did read right there is a recent thread

Originally Posted by All-Or-Nothing

I'm on the hunt for a rear diff and I just don't know which years of the X5 are compatible with my 2004 645 Vert. Also does a certain model have the better ratios that will improve my acceleration.


Any help will be greatly appreciated.

Read the thread below, this is Jpeg's review of his X5 differential upgrade courtesy of Jim Blanton at Performance Gearing, which he highly recommends. You should send an email to Jim and ask what years are compatible and perhaps if he has one available. I am sure he will share his knowledge with you.

I have spoken with Jim several times as I am considering a full Limited Slip Differential upgrade along with a gear set change to a 3.91 or even a 4.13 (trying to remember the 4 final number, it has been a while and I am not home in front of my old emails). The X5 upgrade is less expensive but harder to find, as Jim told me the X5 that JP bought was in excellent shape and of course less than buying the LSD that he builds.

The cost for a LSD with 3.91 that matches our 6 is $3,000. This price is posted on his website, so an X5 differential comes in less than that.

http://www.bimmerfest.com/forums/sho...4&highlight=91

^^^^^


Thanks for that info.

I can't seem to find an Email address for them so I will have to call.

There are quite a few X5 diffs on Ebay in the $300 to $600 range and brand new ones right around $1200. Soon as I find out the correct years and models I am buying it immediately.

I will report back what he says after I call.

Thanks again.

The 04/05 X5 4.8 if I recall properly.

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Originally Posted by JPEG23

The 04/05 X5 4.8 if I recall properly.

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Woo Hoo found a 4.10 rear for only $500 bucks. Also found a 3.64 rear for even less. Now to make sure it will fit and work in my car.

I'm sure the, 4.10 doesn't, I believe only the 3.91 on the 4.8 X5 fits the 6er.

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Those diffs will make your car seem more like a rocket, but may make long trips a bit more harsh if your RPMs are too high. If you have an auto transmission you may not care.

My 4.8is cruises at around 2k RPMs @ 80mph, which is awesome.

2200 rpm(or so) at 75-80 mph

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Originally Posted by JPEG23

I'm sure the, 4.10 doesn't, I believe only the 3.91 on the 4.8 X5 fits the 6er.

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Thanks....I don't think I would want 4.10s anyways. (although I had a Mustang with 4.30s that was a blast to drive) I will keep my eye out for the 3.91 rear.


I tried calling the Jim guy but no answer. There is a 13 hour time difference between us so I may have not calculated my times correctly either.

There has to be some compatibility list on the internet somewhere.....

I found it best to email, use the "ask the pros" part of his website. Fill out the info and it sends him an email. Once he replies to that you can keep the dialog by email.

http://www.performancegearing.com/contact.php

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Okay, now this thread got my blood pumping. Keep it going!

Originally Posted by tampamark

I found it best to email, use the "ask the pros" part of his website. Fill out the info and it sends him an email. Once he replies to that you can keep the dialog by email.

http://www.performancegearing.com/contact.php

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Thanks......


Email sent......hope he replies back soon.

No E-Mail response yet.


I did jack up the car and check my diff fluid and it looks like brand new fluid. Just like it came out of a brand new bottle.

The Plot thickens............

Still no E-Mail response from this guy.


My brain is telling me it's not the diff. Any other suggestions on what might be my problem?????

Woo Hoo finally got a response to my E-Mail. Here is a direct quote.

Chris,



Only one BMW used the gearset you need. Look for an E53 X5 - 4.8is only. In the US, that would be 1/03 to 7/06.




Jim Blanton

Performance Gearing

And the highest gearing on that car was the 3.91

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When you change to the X5 3.91 rear differential, does the computer sense the gear change and adj for correct speed indication? Or maybe the speedo reads from a different location that the trans tailshaft?

Originally Posted by speedharris

When you change to the X5 3.91 rear differential, does the computer sense the gear change and adj for correct speed indication? Or maybe the speedo reads from a different location that the trans tailshaft?

I believe I am the only one to actually have done this mod; and, I have had no discrepancies in my speedometer and actual speed.


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Thanks JPEG23
The computer must get it's speed input from the front or rear wheels and not the drive shaft, I'm looking for a differential now.
Am I to understand that it is only a X5 4.8is 2003-2007?

Correct, and you won't regret it; however, the caveat, your MPG does suffer, especially in stop-and-go traffic.

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I didn't buy it with MPG in mind...;-}The closest thing I have to 20MPG is my diesel Excursion @19.6 MPG...;-}