DIY: How To Swap a Differential (plenty of pics)

**Jeffrie** · 11-26-2005, 06:06 PM

Mine did too, don't notice anymore.

**encasemyheart** · 11-28-2005, 11:54 PM

I'm doing this tomorrow and away from home so I don't have my tools aside from a ratchet and jacks and whatnot. Will have to go and buy everything from Autozone or whatever. Can anyone tell me what size wrenches are needed? I have the E12 torx, looks like maybe 17mm for the diff bolts, 16 mm wrench for the driveshaft to diff, 14mm for the sway bar bolts and 10mm for exhaust bolts?

Anyone? So I don't have to buy all kinds of stuff I don't need hoping it works.

Thanks.

**encasemyheart** · 11-28-2005, 11:54 PM

I'm doing this tomorrow and away from home so I don't have my tools aside from a ratchet and jacks and whatnot. Will have to go and buy everything from Autozone or whatever. Can anyone tell me what size wrenches are needed? I have the E12 torx, looks like maybe 17mm for the diff bolts, 16 mm wrench for the driveshaft to diff, 14mm for the sway bar bolts and 10mm for exhaust bolts?

Anyone? So I don't have to buy all kinds of stuff I don't need hoping it works.

Thanks.

**Jeffrie** · 11-29-2005, 07:27 AM

18mm for diff bolts, need a 13mm wrench and a ratchet for head and nut on the sway bars. 16mm is correct for the driveshaft, a 1/2 lenth extension helps with removal of the C.V. axles, 14mm hex for filling the diff fluid (do before install PITA after). Some advise first thing disconnect the speed sensor conector get's in your way when you forget.
For a 318 diff this is all that you need.

**clumpymold** · 11-30-2005, 03:13 AM

Originally Posted by encasemyheart

I'm doing this tomorrow and away from home so I don't have my tools aside from a ratchet and jacks and whatnot. Will have to go and buy everything from Autozone or whatever. Can anyone tell me what size wrenches are needed? I have the E12 torx, looks like maybe 17mm for the diff bolts, 16 mm wrench for the driveshaft to diff, 14mm for the sway bar bolts and 10mm for exhaust bolts?

Anyone? So I don't have to buy all kinds of stuff I don't need hoping it works.

Thanks.

A breaker bar for the 16mm wrench would help tremendously too.

**leedawg** · 11-30-2005, 03:16 AM

Yeah and just so you kjnow I dont think you can get a socket on those Driveshaft nuts, so id get a box end wrench for those.

**Tommy R** · 11-30-2005, 07:30 AM

Originally Posted by leedawg

Yeah and just so you kjnow I dont think you can get a socket on those Driveshaft nuts, so id get a box end wrench for those.

Yup. I used a Quickwrench.

Tommy

**5speed300** · 11-30-2005, 08:51 AM

Yeah using those quickwrenches woudl help tremendously. I had to use a regular box end wrench of the driveshaft bolts and it took forever, only to find out after completely removing and installing the diff. that my dad had a full set of those quickwrenches.

**tatawaki** · 03-15-2006, 04:03 PM

sorry to bring up an old thread but I'll be replacing my torx bolts however I'm not sure which ones to get:

I have
33-21-1-227-664 (325) 45mm long
33-21-7-507-845 (325) 43mm long
EDIT: found this part Number: 33-21-1-227-279 (from M3) 50mm long
dealer says they've updated the 33-21-1-227-664 to the 33-21-7-507-845. but the 664 bolt is longer by 2 to 3 threads.

I'm upgrading to a 3.38 using the m3 output flanges and bolting it to a 325. which torx screws do I need?

EDIT2: another thing noticed is the following:
http://www.realoem.com/bmw/showparts...68&hg=33&fg=25
for the M3 the Drive Shafts have the following: LK=94MM/D=27MM
http://www.realoem.com/bmw/showparts...68&hg=33&fg=25
for the 325 the Drive Shafts have the following: LK=86MM/D=27MM

so what does the LK mean?

I'm assuming that the output flanges are different from the 325 but is that only in thickness? Maybe the LK=94MM means that its thicker and that you should use the 50MM bolts?

**GottaLoveAvus** · 03-15-2006, 08:11 PM

nice Al Pacino quote... lol

**tatawaki** · 03-17-2006, 02:46 PM

Bump - I bought also the M3 Torx Bolts just in case. any idea's what LK means?

**4Life** · 05-18-2006, 11:32 PM

I know its kind of late but I think the LK means length followed by D for diameter.

On another not, I stripped 2 axle bolts trying to get them off, I will be grinding those heads off tomorrow unless someone has and easier way? I couldnt fit my little dremelt cutoff disks in there.

**tatawaki** · 05-18-2006, 11:52 PM

Update: I had to use my 325 output flanges the diameter is larger on the m3 output flange. I ended up using the standard 325 torx bolts.

**theruss1an1** · 05-19-2006, 12:02 AM

Just finished taking notes and will be doing this tomorrow.

Just need to pick up some royal purple diff fluid and torx sockets. I can just fill the diff using the speed sensor hole cant I?

-Serge

**clumpymold** · 05-19-2006, 04:52 AM

Originally Posted by theruss1an1

Just finished taking notes and will be doing this tomorrow.

Just need to pick up some royal purple diff fluid and torx sockets. I can just fill the diff using the speed sensor hole cant I?

-Serge

You can? I thought you had to remove that diff bolt using the really random torx socket. Something like 40 or 44. Don't remember now but I DO remember buying one on eBay only to find out I can't even fit my socket wrench in there.

**leedawg** · 05-19-2006, 09:31 AM

Um the only torx socket required is an E12 for the half shaft bolts everything else is standard metric heads.

**clumpymold** · 05-19-2006, 01:37 PM

Originally Posted by leedawg

Um the only torx socket required is an E12 for the half shaft bolts everything else is standard metric heads.

He was talking about refilling the differential fluid. It requires a 14mm hex socket.

http://forums.bimmerforums.com/forum...ht=diff+socket

**theruss1an1** · 05-19-2006, 02:24 PM

So I cant use the speed sensor hole to drain fluid in? So I gotta find a 17mm allen.

-Serge

**4Life** · 05-19-2006, 02:43 PM

Got my diff out today, hoping to only see some allen bolts backed out and instead I find 1/3 of my pinion gear missing and large chunks of it all over my diff!!!

The weird part is I cant see anything that worked loose to cause this kind of damage.

**wcbimmr328** · 05-19-2006, 04:00 PM

Sorry about the noob question but the search is down. What is the point of putting in another differential? I really appreciate your response

**M52 POWER!** · 05-19-2006, 04:05 PM

4life that is NUTS. Was it making any crazy noises before you removed it?

wcbimmer, a higher gear ratio will improve acceleration quite a bit!

**4Life** · 05-19-2006, 05:54 PM

Must be the massive horsepower my stock 328is with a Dinan intake is making LOL.
I noticed a faint barely audible clicking noise for about 10 minutes, then it suddenly turned into a loud clunking noise. I drove the remaining 2 KM home with no problem aside from the noise. After taking it apart and assesing the damage Im surprized I was able to drive it home.

**theruss1an1** · 05-19-2006, 07:31 PM

JB weld, I swear it will work.

-Serge

**CRYPTiC** · 05-20-2006, 12:27 AM

Originally Posted by theruss1an1

So I cant use the speed sensor hole to drain fluid in? So I gotta find a 17mm allen.

-Serge

I read about one board member who created a work-around by putting a bunch of 17mm nuts on a bolt with a 17mm head. I've never changed the diff fluid myself, so I can't vouch for whether this would work or not ...

**Jeffrie** · 05-20-2006, 03:40 AM

^^^ 17mm no.
A 14 mm yes.
Just need to lock two nuts togeter or weld one.
Although the proper hex tool only cost 5 bucks.

Thread: DIY: How To Swap a Differential (plenty of pics)

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