Differential DYI instructions

Differential installation instructions. These instructions are only as a guide for people to swap differentials. Please read through all the instructions before attempting to install on your own. I take no responsibilities for any inaccuracies or problems/damage you may encounter from using these instructions. Please consult your shop manual. Sorry about the poor photos. I wasn’t planning on doing a differential write up. Most of the pictures were taken after I installed the differential. That said… lets begin.

1. Remove rear sway bar. (Check DYI section in E46 fanatics)

2. Remove Exhaust hangers and let it dangle. Unscrew the 2 rubber hangers on the exhaust. 4 M8 nuts (you'll need the room for the next step.) (Fig 1.)

3. Remove Rear suspension reinforcement brace. There's also a heat shield on the exhaust side (2 bolts). Remove the heat shield first. (Fig 2.) The Brace is held down by 6 bolts. Remove the inner 4 small bolts first. Then remove the 2 outer bolts. (Fig 3) (Tightening torque - M12 nut 57 ft-lbs, M8 bolt 8.8 grade 15 ft-lbs, M8 bolt 10.9 grade 22 ft-lbs)

4. Disconnect the drive shaft from the differential input flange. 4 M10 Torx Bolts. (Fig 4) Pry the drive shaft off the differential input flange with a screwdriver. (Tightening torque - M10 Torx bolts 61 ft-lbs)

5. Disconnect the right and left drive axels from the differential output flanges. Each axel has 6 M10 external Torx bolts. (Fig 5) (Suspend the right/left axels with a wire, Fig 6) (Tightening torque - M10x46 59 ft-lbs)

6. Remove the Differential. Support the differential with a transmission jack. The Differential is held down by 3 bolts. 2 M12 bolts in the front, 1 M14 bolt on the rear. Remove the 2 front ones first (Fig 3), then remove the rear one (Fig 7). (Tightening torque – M12 Bolts 70 ft-lbs, M14 Bolt 128ft-lbs) (when reinstalling, insert all 3 bolts finger tight. Tighten the 2 front bolts first, then tighten down the rear bolt).
Work the differential off the car by pulling it towards the rear end. Slowly lower the jack as you pull it out. (you need 2 people for this part.)

7. Install your new rear differential. Flow the steps in reverse.

Misc.
I filled up the Differential with new differential gear oil before I put it on the car. It’s just easier that way. (differentials always come without differential oil) I just used Mobil 1 Synthetic 75/90 since that's what they had at Pep Boys. (oil specification BMW SAF-XO synthetic oil. 0.95 US qt) The drain/fill plugs use a 14mm hex wrench. it's kinda hard to find. I used a nut that was 14mm in diameter instead. (any hardware store will have one for about 8 cents) (Tightening torque 14mm plug 52 ft –lbs).
The input/output flanges use External Torx bolts. You need an E12 external torx socket. You can buy the sockets at Sear (Sears item #00947733000 Mfr. model #26750)

Fig1


Fig2


Fig3


Fig4


Fig5


Fig6


Fig7


Enjoy

very good write up

oh... forgot one thing. When replacing the differential fluid, buy new seal rings. part # 07-11-9-963-355 They were 12 cents a piece at my local BMW dealer. You need 2. 1 for the drain plug, 1 for the fill plug.

Great write up. Thanks bro for sharing

Complete list of E46 gear ratios. Includes automatic final drive ratio.

Model...........1.......2.......3.......4.......5.......6... ....reverse Final...Final.Drive
............................................................ ............Drive...From.Automatic
323i/ci.........4.23....2.52....1.66....1.22....1...............4 .04....3.07....3.46
325i/ci.........4.23....2.52....1.66....1.22....1...............4 .04....3.15....3.46
328i/ci.........4.21....2.49....1.66....1.24....1...............3 .85....2.93....3.46
330i/ci.........4.21....2.49....1.66....1.24....1...............3 .85....2.93....3.38
330i-6sp........4.35....2.50....1.66....1.23....1.......0.85....3 .93....2.93....3.38
330i-zhp........4.35....2.50....1.66....1.23....1.......0.85....3 .93....3.07........

323cic..........4.23....2.52....1.66....1.22....1........... ....4.04....3.46....3.46
325cic..........4.23....2.52....1.66....1.22....1........... ....4.04....3.46....3.46
330cic..........4.21....2.49....1.66....1.24....1........... ....3.85....3.07....3.38
330cic.6sp......4.35....2.50....1.66....1.23....1.......0.85 ....3.93....3.07....3.38

323i-touring....4.23....2.52....1.66....1.22....1...............4 .04....3.46....3.46
325i-touring....4.23....2.52....1.66....1.22....1...............4 .04....3.46....3.46

325xi./touring..4.21....2.49....1.66....1.24....1...............3.8 5....3.23....3.46
330xi...........4.21....2.49....1.66....1.24....1........... ....3.85....3.07....3.46
330xi.6sp.......4.35....2.50....1.66....1.23....1.......0.85 ....3.93....3.07....3.46

z4.2.5..........4.23....2.52....1.66....1.22....1........... ....4.04....3.46....3.64
z4.3.0..........4.35....2.50....1.66....1.23....1.......0.85 ....3.93....3.07....3.46

The best place to pickup a used differential is a salvage yard. You can get a brand new one from the Dealership, but it'll cost about $1200. Used differentials from Salvages yards cost about $200-700. (depends on Ratio, age, mileage, which salvaged yard you call...). 3.46 diff are by far the cheapest. They're available from most Automatic tranny e46s.

check www.car-parts.com

(example search)
Search
year - 2001
make - BMW 325i
Part - carrier (also see differential)
all States

Differentials are very heavy, ~70 lbs. it'll cost about $45 to ship via UPS.

E46 Diff ratios listed by BMW ETK.
*Note... not all ratios were available in the US.

33 10 7 508 099 --- 330cic manual 3.07
33 10 7 505 394 --- 330cic auto 3.38
33 10 7 505 390 --- 330ci manual 2.93
33 10 7 505 394 --- 330ci auto 3.38
33 10 7 505 390 --- 330i manual 2.93
33 10 7 505 394 --- 330i auto 3.38
33 10 7 504 532 --- 330xi auto l 3.15
33 10 7 500 785 --- 330xi manual 3.07
33 10 7 500 781 --- 330xi auto 3.46


33 10 1 428 128 --- 328ci manual 2.93
33 10 1 428 344 --- 328ci auto 3.46
33 10 1 428 130 --- 328ci auto 3.07
33 10 1 428 128 --- 328i manual 2.93
33 10 1 428 344 --- 328i auto 3.46
33 10 1 428 130 --- 328i auto 3.07

33 10 7 503 230 --- 325cic ??? 3.23
33 10 7 503 245 --- 325cic auto 3.38
33 10 1 428 344 --- 325cic ??? 3.46
33 10 7 500 028 --- 325ci manual 3.15
33 10 7 503 230 --- 325ci auto 3.23
33 10 1 428 344 --- 325ci auto 3.46
33 10 7 500 028 --- 325i manual 3.15
33 10 7 503 230 --- 325i auto 3.23
33 10 1 428 344 --- 325i auto 3.46
33 10 7 500 783 --- 325xi manual 3.23
33 10 7 500 783 --- 325xi auto 3.23 ???? ETK lists the same for manual and auto???
33 10 7 500 028 --- 325iT ??? 3.15
33 10 7 503 230 --- 325iT auto 3.23
33 10 1 428 344 --- 325iT auto 3.46
33 10 7 500 783 --- 325xiT manual 3.23
33 10 7 500 783 --- 325xiT auto 3.23 ???? ETK lists the same for manual and auto???

33 10 7 503 230 --- 323cic ??? 3.23
33 10 7 503 245 --- 323cic auto 3.38
33 10 1 428 344 --- 323cic ??? 3.46
33 10 1 428 130 --- 323ci manual 3.07
33 10 1 428 344 --- 323ci auto 3.46
33 10 1 428 130 --- 323i manual 3.07
33 10 1 428 344 --- 323i auto 3.46

bUMP

Originally Posted by VanosMan

bUMP

-bump!

Pardon my asking, what is a good site or thread that can tell me what differentials actually do?

Hi sycE46!!

Can you tell me how many litres of the diff fluid did you pour into your new rear diff??

Thanks!!

Wilson

Originally Posted by wilman2772

Hi sycE46!!

Can you tell me how many litres of the diff fluid did you pour into your new rear diff??

Thanks!!

Wilson

The diff only needs 0.95 US quarts. If you're filling the diff while it's off the car, you'll only need 1 bottle. If you're filling the diff while it's on car, you'll probably need fluid pump and 2 quarts of diff fluid.

I highly reconmend filling the diff while it's off the car. It's much easier to fill.

The bottle of diff fluid I bought was exactly 0.95 quarts.

Originally Posted by sycE46

The diff only needs 0.95 US quarts. If you're filling the diff while it's off the car, you'll only need 1 bottle. If you're filling the diff while it's on car, you'll probably need fluid pump and 2 quarts of diff fluid.

I highly reconmend filling the diff while it's off the car. It's much easier to fill.

The bottle of diff fluid I bought was exactly 0.95 quarts.

Thanks for the reply bro!!

I'm changing my rear diff cover, thus I'll need to drain away all the OEM oil....U mean all I need is 0.95 quarts after the cover is in??

I'll be pouring in the new diff oil with the rear diff off the car thou..

Cheers!!

Wilson

Is removing the rear sway bar the same as the front, it says check the DIY section in tech on this forum but there is only instructions for the front...

Also what kind of oil/fluid should i purchase?

Any help would be appreciated since i will be doing this tomorrow....

Originally Posted by E46325Ci

Is removing the rear sway bar the same as the front, it says check the DIY section in tech on this forum but there is only instructions for the front...

Also what kind of oil/fluid should i purchase?

Any help would be appreciated since i will be doing this tomorrow....

Removing the rear should be pretty much the same as the front but trickier, since it has to be wiggle in/out because of the lack of space.

As far as fluid, people recommend using Redline products, google for it.

Good luck.

Can I ask a dumb question?

Why do you guys swap differentials instead of swapping gears and doing an easy diff rebuild (clutch packs/springs) and a diff fluid swap?

Originally Posted by stickaz

Can I ask a dumb question?

Why do you guys swap differentials instead of swapping gears and doing an easy diff rebuild (clutch packs/springs) and a diff fluid swap?

That's a question I personally don't have an answer to, but maybe someone else might explain why.

Originally Posted by stickaz

Can I ask a dumb question?

Why do you guys swap differentials instead of swapping gears and doing an easy diff rebuild (clutch packs/springs) and a diff fluid swap?

Diffs are cheap. They contain the final gear ratio. Easier to just buy one and swap it, then to open up the diff and rebuild it.

Originally Posted by E46325Ci

Is removing the rear sway bar the same as the front, it says check the DIY section in tech on this forum but there is only instructions for the front...

Also what kind of oil/fluid should i purchase?

Any help would be appreciated since i will be doing this tomorrow....

The rear sway bar is pretty easy to remove. (then again.. .I'd done it about 5-6 times)

1. Jack up the rear end of the car.

2. remove both rear wheels.

3. From the top of the control arms, you should be able to see the bolt that connects to the sway bar endlink. remove the bolt. (I think it's behind the spring) Do the the same to the other side.

4. Go under the car and Remove the 2 tabs that hold the sway bar in place. It's a brass bracket that only has 1 bolt in it. Remove the bolt and nut.

5. Wiggle the sway bar out. If you have problems wiggling it out, it's probably b/c the endlink is getting in the way. just bend the endlink so it clears whatever it's snagging on. (end link is connected to the sway bar with a rubber bushing)