Best diff upgrade for 540i 6 spd??

[Iamthebull]

555 USD, people selling m5 diffs on FB marketplace for that price

Only problem I'm too far away lol

Oh my. I always forget about marketplace. Good thinking! At the same time, sometimes you have to pay out the wazoo for shipping.

[Bmwe39528i1998]

Driveshaft our, exhaust out, half shafts out, ready to take the diff out....

I was reading someone drilled a hole through their spare tire compartment to access a diff bolt, wtf lol!

But if I'm putting a Quaifie thing into my diff, do I still need to first fid 3.15 diff or does it matter? I thought Quaifie was replacing the intervals of the diff.

I also found a rebuilt m5 diff for $1500 but the guy said he didn't set the lash properly. I think it's too much as I need to buy the drive shaft and half shafts as well...

[JimLev]

You disassemble your diff and install the Quaife in your diff. You don’t need a different driveshaft or half shafts.
Did you look at Phillys post?
Use a special stubby socket to get at that one nut, no need to cut a hole in the spare tire well.

[philly98540]

As Jim said, take a look at my thread for details on how to install a Wavetrac or Quaife into your existing diff or another open diff. If you keep your existing 2.81 open diff, installing a Wavetrac or Quaife will not change the gear ratio. I like the 2.81 myself, but if you want a different ratio, you will need to get new ring and pinion for your diff or get a different ratio diff and retrofit that. Or get an M5 diff and all the stuff needed to fit that. I'd stay away from the unit you talked about above if the lash is not good. Might be a can of worms.

[Bmwe39528i1998]

Alright I'll just keep the diff I have, I'm not finding anything else and I need to get this project going. It's time for action. Will catch you in your other thread!

[Henn28]

Pics please!

[JimLev]

Henn, grab a cold one and start reading.
https://www.bimmerforums.com/forum/s...-DIY-with-Pics

[seagreen323i]

You disassemble your diff and install the Quaife in your diff. You don’t need a different driveshaft or half shafts.
Did you look at Phillys post?
Use a special stubby socket to get at that one nut, no need to cut a hole in the spare tire well.

I put a standard socket in a set of vice grips. Works a charm.

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[Bmwe39528i1998]

This might be a noob question, but if I buy the pinion and ring gear, it will make my differential 3.15?

https://www.ebay.ca/itm/115709089409...mis&media=COPY

- - - Updated - - -

Based on Henn28 message,
X5
4.4i = 3.64
3.0i = 4.1
3.0d = 3.23
4.6is and 4.8is= 3.91

I understand the higher the ratio, the faster the acceleration feels? In that case why not get 4.1 instead of 3.15?

[seagreen323i]

This might be a noob question, but if I buy the pinion and ring gear, it will make my differential 3.15?

https://www.ebay.ca/itm/115709089409...mis&media=COPY

- - - Updated - - -

Based on Henn28 message,
X5
4.4i = 3.64
3.0i = 4.1
3.0d = 3.23
4.6is and 4.8is= 3.91

I understand the higher the ratio, the faster the acceleration feels? In that case why not get 4.1 instead of 3.15?

Mainly because the crusing rpm on the highway at 60 mph with a 4.10 rear end ratio would be 2700 rpm. Compared to the 1900 rpm with a 2.81 it demolishes your mpg. Also, first gear would basically be useless with redline being at about 27-28 mph

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[Bmwe39528i1998]

I see. I found this E39 528i and according to realoem, the driveshaft ratio is 4.1. How is this possible or am I misreading it?
WBADD6324WGT90748

[CPHES]

I think Automatic 528i cars came with a 4:10 when they got the GM 4 speed. There is a 4:10 out there - I think it is the small case diff?

[Bmwe39528i1998]

Yeah it says 188k. I'm no expert in diffs and gears, but it seems like 4.10 is ok for automatic transmission, but too much for manual transmission in terms of fuel consumption?

Right now I found m5 diff with driveshaft for $2100 including shipping. I'll be missing the halfshafts, or at least the flanges I believe.

I'm not sure if anyone compared m5 diff vs wavetrac?

[taz.]

As far as I know, the 528IA came with a 3.46 on the 5 speed and 4.10 on the 4 speed.
I am swapping my M52TUB20 engine, automatic, that originally came with 3.64 diff to a M52TUB28.


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[taz.]

Yeah it says 188k. I'm no expert in diffs and gears, but it seems like 4.10 is ok for automatic transmission, but too much for manual transmission in terms of fuel consumption?

Right now I found m5 diff with driveshaft for $2100 including shipping. I'll be missing the halfshafts, or at least the flanges I believe.

I'm not sure if anyone compared m5 diff vs wavetrac?

The M5 diff is a 3.15 IRC.
Look for an automatic 530, it should 3.46.

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[BimmerBreaker]

Aren't there other differences (case size? Output flange/axel/driveshaft compatibility?) between I6 and V8 diffs? It's been awhile since I looked into this for E39's but I thought they were not directly compatible.
I do think an M5 diff is plug and play in a 540. May need to pop the 540 output flanges into the M5 diff though (again not positive but on many BMW's this is the case)

Regardless a 4.1 is too aggressive. Probably *way* too aggressive. At some point the benefit of faster acceleration is offset by the increased time spent shifting, and this actually ends up making a car slower 0-60, or in a 1/4 mile.
The 4 speed E39's having a 4.1 makes sense because in a 4 speed the transmission gears are longer. You end up with a similar total gear ratio to a car with more transmission gears and less aggressive diff ratio.

Sweet spot is probably around 3.4x - 3.6x depending on intended usage.

[Bmwe39528i1998]

Hey Taz, how's the swap going???

I'm looking on all the scrap yards, very few E39 left. I think E39 is becoming obsolete. E39s are very hard to come by.

This was posted above.
_E53 X5 OE diff ratios_
4.4i = 3.64
3.0i = 4.1
3.0d = 3.23
4.6is and 4.8is= 3.91

Lots of E53 4.4, so I'd be happy to settle for 3.64 gear ratio.
E53 diesels in canada, I can just forget it, not even a thing.
4.6 and 4.8 are possible to find, but 3.91 ratio seems too high based on what people are saying.

The E39 540i diff is showing TYP 220K, while E53 X5 4.4 is showing TYP188K.
So it means they're different sizes?
Or I can just change the covera?
Or do I take internals from TYP188K and put them into TYP 220K?

[taz.]

Hey Taz, how's the swap going???

I'm done painting the engine, I'm waiting for some miscellaneous parts, like Reizosil, thread sealer, all the o-rings, and a small torque wrench.
Funny enough, like all the other normal stuff, one can buy off the shelf in a normal country, guess what... in Denmark, you can't. You literally need to order everything online from other normal countries like Germany.



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[BMW4RE]

As far as I know, the 528IA came with a 3.46 on the 5 speed and 4.10 on the 4 speed.
I am swapping my M52TUB20 engine, automatic, that originally came with 3.64 diff to a M52TUB28.


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Well, I for one am happy to have the 4.10 diff in my '99 528, M52TU (That's what I've heard anyway,). While I rarely punch the throttle, especially off the line, I did today. Moments after some ricer passed a group of cars, including me, by making his own lane down the median on a surface street, spraying us with gravel as he approached a blind curve, I had some yo-yo run up my rear end at a red light. It was very red for me, but this aggressively driving female of the species really wanted me to run it so she could run it worse. I just don't run red lights. It's not the ticket, it's the dice roll. Obviously quite peeved with me, she then pulls next to me on my right, where there is nothing but a bike lane, and prepares to hole-shot me when the light changes. Must be all of that NHRA stuff I'm watching on TV at night, but when the "tree" flashed green, I smoked her off the line. :-) I think the erratically driving old guy left her in shock. I forgot that this little puppy can be pretty quick off the line. Granted, she was in a Camry or something, so it wasn't a big win on hardware. It really was no contest until she made it one. Pass me in my Jeep, shame on you. Pass me in my Bimmer, shame on me. Especially in a Camry. ;-) Cheers.

[BimmerBreaker]

The 4 speed gearbox in a 98 528i has a first gear gear ratio of 2.4. The V8 manual transmission 6 speeds have a first gear ratio of 4.2. This is why the 4 speed auto cars have a 4.1 diff - to keep acceleration respectable. If you put that ratio behind a 6 speed car, you'll have no usable first gear.

Out of curiosity I researched this and confirmed that medium and large case diff internals do not interchange. I was wondering where this went awry and it looks like someone in the thread posted a 6 cyl medium case diff, someone else saw that and shared medium case E53 ratios, but those X5 diffs can't be used in the E39 V8 large case diffs. The X5 used medium case diffs with the V8's because all E53's were AWD, so each diff was not handling much torque relative to the RWD E39.

You need internals meant for the large case diff. They are typically expensive, and hard to find, especially in the "good" ratios. If it was this easy to build a better V8 diff then every M5 out there would have a better ratio diff. I think Dinan made a better ratio diff (3.4x maybe?) but the few times I see them come for sale they go quickly and for BIG bucks.

It would also be prudent to ask "do the V8 cars really need a large case diff?". I would suggest, based on the insane power levels some turbo E36 guys shove through medium case diffs, that the answer is "no" - especially for a mostly stock M62 powered car. Of course that is another can of worms and downgrading from a large case to a medium case, merely for a better ratio, is almost certainly not worth the hassle. There is more involved in that than just swapping the diff itself.

Personally I would just buy the M5 diff and be happy.

[Bmwe39528i1998]

Thanks for making sense of the confusion!

I just stumbled on this Facebook post.

Apparently E65 diff with 3.38 ratio is a direct internal swap into E39 v8 diff??

Just lost that post, trying to find it again...

[Bmwe39528i1998]

https://www.facebook.com/share/p/7Qd...ibextid=oFDknk

[BimmerBreaker]

I can't follow that link, but it wouldn't surprise me if e65 stuff worked as those are also large case diffs. If so, that likely means you could also use e60/e63 V8 diffs as those were available in 3.46 ratios.

For the record though, swapping internals is pretty involved work. You'll need to set backlash and preload. Easy to mess up and easy to not know you messed up and break things once back on the road.

[taz.]

Well, I for one am happy to have the 4.10 diff in my '99 528, M52TU (That's what I've heard anyway,). While I rarely punch the throttle, especially off the line, I did today. Moments after some ricer passed a group of cars, including me, by making his own lane down the median on a surface street, spraying us with gravel as he approached a blind curve, I had some yo-yo run up my rear end at a red light. It was very red for me, but this aggressively driving female of the species really wanted me to run it so she could run it worse. I just don't run red lights. It's not the ticket, it's the dice roll. Obviously quite peeved with me, she then pulls next to me on my right, where there is nothing but a bike lane, and prepares to hole-shot me when the light changes. Must be all of that NHRA stuff I'm watching on TV at night, but when the "tree" flashed green, I smoked her off the line. :-) I think the erratically driving old guy left her in shock. I forgot that this little puppy can be pretty quick off the line. Granted, she was in a Camry or something, so it wasn't a big win on hardware. It really was no contest until she made it one. Pass me in my Jeep, shame on you. Pass me in my Bimmer, shame on me. Especially in a Camry. ;-) Cheers.

In the M52TU, you should have 5hp19 5 speed steptronic, thus a 3.46 diff.
The 4.10 came only on the 4 speed automatics.
Manual 528s have a 2.93 and tourings have 3.07.
@Bmwe39528i1998 I think your best bet would be a 3.46 or max a 3.64 as you have a 6 speed.

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[BimmerBreaker]

M52TU's used 4 speed automatics up until production month 9/99