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

[RocketyMan]

Alrighty....so I've been fed up with going down the highway in top gear at 3500 rpms going around 70mph. I tried looking at getting a AWD 6 spd transmission, but the setup is completely different--unfortunately. My differential ratio for my manual 5sp X5 is 4.10s. And with no real "over-drive" top-gear, the only thing I can do is change the front&rear diffs.

I did not see any good write-up for 3.0 E53s changing front diffs. And I did not want to drop my subframe like TIS suggested neither. All I could find with VAST google search's is that, yes you can squeeze the front diff out of the car barely.

So off to changing my front diff first!

[RocketyMan]

So after some research on what diffs I could use for the X5, the lowest ratio I could find would be from the 4.4L E53s only. They use 3.64 differential ratio. To me, this should be well enough. And going 70ish mph @3500 rpms would then drop to about 3100 rpms. I think this should be fine and hopefully pick up maybe a half mpg or two. In addition, maybe my 1st gear will be more useful.

Below you should see the pictures of this process.

Steps:
1. Remove both front CV axles left to right (this is REALLY easy to do with just removing the lower control arm at the K-member and removing the tie-rod ball joint--I don't know why ppl remove the whole knuckle just to replace a CV axle -_- )

2. Remove the drive shaft to the input gear of the front diff
a. Mark the bolts to the flex joint as there is a specific orientation for this to go apparently, should be 3, 16mm bolt-nuts and 3 flange-bolts
b. Once all fasteners are removed, pry the drive-shaft flange with a screwdriver towards the x-case, notice this pushes shaft deeper in splines which you can then remove flex joint and mounting flange

3. Drain your diff and get ready to loosen all 4 bolts to the oil pain, also remove vent tube
a. All 3 short bolts can be easily removed via 16mm socket, but the long bolt needs to stay in the diff housing until you can rotate it down to remove the bolt (NOTICE! These are blind holes on the side of the oil pan--that are aluminum!! Take SPECIFIC precaution when torquing and ONLY do by hand. DO NOT use power tools as you can hydro-lock your bolt and blow out your threads.)

4. Now rotate diff and move towards the rear, disconnect oil pan sensor if you think it will get in the way/break
a. Rotate diff input flange down to help aid in removing
* it might help loosening motor mount top-nuts so the engine can wiggle some more for added clearance

5. Installation is obviously the reverse. Do take note on when tightening the bolts to the oil pan! Make sure to clean threads on bolts. Don't use power tools for this! Tighten by hand! Only tighten to about 40 ft*lbs or so.


Couple of notes:
1. When reinstalling new diff, it might help taking the edge off various sharp edges, like the input machined surface, oil pan side surface--you'll notice on my last picture
2. I actually pounded with a hammer slightly the left side motor mount area just so re-installation of the new diff would be much easier--and it was, but what you see is the sharp edge on the diff digging into K-member. It might be better not to do this, but no welds were broke--so I'm okay with it.
3. Luckily, I still had good enough splines on the drive shaft to the diff as they look a little wore out. It was mostly rusty when I took it out which I wonder if it contributed to a lot of the wear. I made sure to grease up the splines real good upon re-installation. These are heat-treated splines so I'm not worried after 185k miles how these look.
4. Don't be afraid to mark things with your grease pen--this really helps with identifying what goes where.
5. You can easily identify the diffs with the tag on top, but the writing quickly fades away the more you wipe it

[RocketyMan]

During the whole diff swap, i'm swapping out new steering components. After 185k miles, I think it time to change all of these STOCK components. You can see the BMW insignia on every steering component.

The rubber on the thrust joint is completely shot as there are cracks in the rubber throughout. ALso, the lower control arm ball joint rubber has cracks all in it too.

I will actually be re-using the thrust control arms and just replacing the rubber bushings. Shouldn't be too bad to replace. Just need to press out old and press in new. $30 for one new assembly or just $13 for a new rubber bushing. Shouldn't be too bad, and plus I didn't see ANYONE post doing a thrust control arm rebuild.

[Purplefade]

Brother that is impressive - Nice work! I know how much fun just the suspension alone can be and, unfortunately I share your experience with the diffs but for a different reason... my rear decided to eat the ring gear at about 90k, wasn't "real" hard to pop in the rear (mine are 4.10) but I can't imagine tackling the front on my 4.4i...

[crystalworks]

I am definitely impressed with having the idea and actually going through with the swap. Most ask and never do anything about it. But, I think I would have dropped the subframe before hammering on it. JMHO though obviously. You keep, keeping on. I'm definitely interested to hear in the results after you're done.

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

[wpoll]

Ummm.... is anyone going to point out the need to change the rear diff at the same time?

[wpoll]

Originally Posted by RocketyMan

… I will actually be re-using the thrust control arms and just replacing the rubber bushings. Shouldn't be too bad to replace. Just need to press out old and press in new. $30 for one new assembly or just $13 for a new rubber bushing. Shouldn't be too bad, and plus I didn't see ANYONE post doing a thrust control arm rebuild.

I went down this same path, since full thrust control arms are prohibitively expensive down here (the two Meyle HD bushes cost me $160!). Rebuilding the old ones is an easy job with a press and saves discarding two very large, still serviceable parts of the car.

[andrewwynn]

My two x5 3.0 turn about 2600 at 75 mph. 3500 is way too high I hope you are exaggerating.

3.91/4.1*3500=3337. It's not a very big difference.

[e39_touring]

Originally Posted by andrewwynn

My two x5 3.0 turn about 2600 at 75 mph. 3500 is way too high I hope you are exaggerating.

3.91/4.1*3500=3337. It's not a very big difference.

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.

[Clavurion]

Originally Posted by e39_touring

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).

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