BMW E53 3.0i -- Front&Rear Differential Change + Other various suspension components

[e39_touring]

Originally Posted by Clavurion

Aren't the rear diffs on auto Typ 188 and on manual Typ 215?

I forget what size, but the housing, ring gear, input & output splines are the same size (I think 210mm sounds right for the ring gear) for all 2001-2003 (pre-LCI). 2001-2003 manuals and IS models have larger stub axle flanges (i.e. you can pop out the stub axles and use them in any diff of the same size).

2004-2006 (LCI) manuals and IS models use the larger differential housing. The stub axle splines are bigger and not interchangeable with the smaller-housed differentials in the auto & all pre-LCI X5's. Some 4.4L LCI models also got the larger rear differential, but I'm not sure any were US models. I think these were only the euro models with no speed limiter (high speed synchronization option?).

[e39_touring]

Oh, a couple of other things, Rockety - I don't see jack stands in your picture. Please tell me that you're not working under the car held up only by the hydraulic jack! Or, are you the one with huge wheels that are tall enough that you can walk around under the car - ha ha.

Which brings me to my second point - make sure when you tighten the front suspension points on the subframe (control arm and tension strut) that the vehicle is resting on its wheels, and you've bounced it a few times to settle the suspension. If you do it with the wheels hanging, your new bushings will tear in short order since they'll be stretched when in normal riding position.

[andrewwynn]

That's crazy the manual has such high ratio in 5th. What happens to your first and second gears? IAM pretty sure the point of the 3.91/4.10 was to help out the smaller engine in the low gears.

Now It makes much more sense to me though I thought 2600 was high for 75 indicated.

[Happy]

Originally Posted by andrewwynn

That's crazy the manual has such high ratio in 5th. What happens to your first and second gears? IAM pretty sure the point of the 3.91/4.10 was to help out the smaller engine in the low gears.

Now It makes much more sense to me though I thought 2600 was high for 75 indicated.

Now imagine that paired with an M54 producing 400 hp.

[e39_touring]

Originally Posted by andrewwynn

That's crazy the manual has such high ratio in 5th. What happens to your first and second gears? IAM pretty sure the point of the 3.91/4.10 was to help out the smaller engine in the low gears.

Now It makes much more sense to me though I thought 2600 was high for 75 indicated.

5th is direct (1:1), which is actually a stronger, more efficient setup compared to overdrive (I think the 6 spd overdrive is 0.83). 1st is crazy low at 5.09:1. With the 4.10 gears, 1st winds out incredibly fast, even in normal driving. I was always worried about being rear-ended after taking off quick and making that shift right away as I'm going up hill. People behind me don't expect that. I suppose that ratio's good when you're hitched to a 6,500 lb trailer (X5 manual max rating) to get it going without burning up your clutch. Or, maybe rock-crawling, too, since there's no 4wd-low setting in the transfer case like there is on, for instance, a 4runner.

The 4.10 gears are quite zippy around town but involve a lot of shifting as there isn't as much range in each gear. It's very strung out at highway speeds of over 70mph.

To me, the 3.64 gears are just about right for everything except maybe that 6500lb trailer. I've towed about 3-3500lbs since doing the gear swap and had no problem getting going at all.

[RocketyMan]

Originally Posted by crystalworks

Edit: Maybe instead of dropping the subframe, the motor mounts could be loosened and the engine raised? Would that provide necessary installation room?

I actually tried raising the engine thinking it would help assist in re installation of the diff, but for some reason did not help at all. Leaving the motor mount top nuts loose helped the most.

Originally Posted by e39_touring

Yep, on a 5 spd manual, it's about 3570 rpm @ 75 mph (actual - indicated is 3 mph less and 100 rpm less).

Putting in 3.64 diffs is a better option and drops the rpm @ 75 to 3170.

I just did this about a year ago and posted about it. You have to pay attention to the axle flanges as they're different between the 3.0 manual and all the auto X5's (except IS models, which are the same as the manual).

Here's the link:

https://xoutpost.com/bmw-sav-forums/...i-3-0-5mt.html

I did this as part of a MAJOR refresh (at only 110k miles) - diff swap, convert to single mass flywheel & new clutch, trans detents and shifter bushings, front suspension overhaul, and oil pan gasket replacement.

I did press new bushings into the tension struts, and it's easy. Just make sure you align the triangle marks and leave 1/4" of the bushing showing on each side. I also recommend dropping the subframe and doing the oil pan gasket because you're 90% of the way there, and your oil pan gasket WILL leak, when not if.

Oh wow...I did not know there was a difference in the rear axle flanges. I will deff need to keep a look out for this when I tackle the rear diff next. Luckily it looks like they easily pop out from the carrier, so I can use them from my original. But why the difference?? I wonder the reason.

My only concern is getting the rear cv axles out. They appear to be original and I think they're going to be rusted in the hub. Also, I think i'm going to have to undo the rear control arms some. Or maybe I wont need to? We'll see.

And yeah, I could've done the oil pan gasket too. But from what I see the majority of my oil leaks coming from is the power steering pump. There's a pinch-clamp that straight up drips from. I don't think the valve cover gasket has been done ever, so I plan on doing that when I rebuild the VANOS gaskets. Also, the trans shifter is quite sloppy. You might know about an easy rebuild? Hopefully I don't have to remove the transmission to stiffen the stick?

[Happy]

Originally Posted by e39_touring

5th is direct (1:1), which is actually a stronger, more efficient setup compared to overdrive (I think the 6 spd overdrive is 0.83). 1st is crazy low at 5.09:1. With the 4.10 gears, 1st winds out incredibly fast, even in normal driving. I was always worried about being rear-ended after taking off quick and making that shift right away as I'm going up hill. People behind me don't expect that. I suppose that ratio's good when you're hitched to a 6,500 lb trailer (X5 manual max rating) to get it going without burning up your clutch. Or, maybe rock-crawling, too, since there's no 4wd-low setting in the transfer case like there is on, for instance, a 4runner.

The 4.10 gears are quite zippy around town but involve a lot of shifting as there isn't as much range in each gear. It's very strung out at highway speeds of over 70mph.

To me, the 3.64 gears are just about right for everything except maybe that 6500lb trailer. I've towed about 3-3500lbs since doing the gear swap and had no problem getting going at all.

The gearing in my opinion is perfect! It gives the heavy E53 with an M54 and manual gear box a very unique driving experience.

I’ve said before 5th gear is amazing, even before the supercharger with only an exhaust and cold air intake I could zip in and out of traffic in this heavy vessel.

With the supercharger, 5th is exotic. With the ratios provided, the E53 can go from 65mph to 95mph with only a quick tap of the throttle.

IMHO... the ratios should not be altered on E53 M54 manual.

[RocketyMan]

Originally Posted by e39_touring

Oh, a couple of other things, Rockety - I don't see jack stands in your picture. Please tell me that you're not working under the car held up only by the hydraulic jack! Or, are you the one with huge wheels that are tall enough that you can walk around under the car - ha ha.

Which brings me to my second point - make sure when you tighten the front suspension points on the subframe (control arm and tension strut) that the vehicle is resting on its wheels, and you've bounced it a few times to settle the suspension. If you do it with the wheels hanging, your new bushings will tear in short order since they'll be stretched when in normal riding position.

Rest assure, I have two jack-stands on their designated body-seam spots!

And yeah, I'll need to joust the suspension several times and tighten the thrust arm and lower control arm bushing as well before I snug down the fasteners.

As far as both carriers I got, I think they're from a 2003 4.4L X5. So hopefully the cv-axle flanges will fit in correctly. Worst case scenario...I wonder if I could just use the different cv-axles If I wasn't able to swap the carrier cv flanges. Hmm...

[Happy]

And something I forgot to mention. You’ll lose MPG. The lower diff ratios will result in more energy needed to get the vehicle up to speed.

[RocketyMan]

Curious...I measured the carrier cv axle flanges. They appear to be 103mm.

I also confirmed that this was out of an '02 4.4L not a '03. But should be close enough and hopefully not have any problems. There's no witness marks for the drain bolt being opened--so I think it still has diff lube in it when the dismantler pulled it.

On that note, the spiders seem VERY "ratchety" and "articulatey" when differentiating the carrier. From my research, there was never an "LSD" option for rear carriers, but wow are these spiders "tight" then...otherwise it acts like a worn LSD almost. The backlash on the drive gear seems very good and tight on the ring. Maybe the cold gear oil is helping with that. No visual leaks anywhere.