24V AWD Swap Knowledge Base

[Nisse Järnet]

Ok thanks! Might have to get a E46 2.93 and take the gearing to a company nearby that make gears and let them look at it :)

[The Dark Side of Will]

it will require more than that. you also have to cut down the ring gear which has to be done precisely.

the pinion is about the same length but the diameter of the bearings is smaller on the E34, and the ring gear is thicker.

The E46 ring gear is thicker? What ratios were you looking at?

[Nisse Järnet]

Shortened the shift linkage ~10cm and picked up my 4th spare gearbox haha :)

[The Dark Side of Will]

The E46 ring gear is thicker? What ratios were you looking at?

I'm not sure I remember correctly. I thought that all the front diffs had the same relationship between the right side carrier bearing and the pinion centerline... meaning that the gear portion of the gearsets should be fundamentally interchangeable if the pinion bearings match up. Obviously the carrier needs to stay with the case, as the carrier bearing widths have to match up.

In all their rear diffs, BMW uses the same carrier across all ratios, and the thickness of the rings gears only varies according to the diameter of the pinion, so I would expect that their front diffs would be made with the same philosophy.

Chris, would you mind refreshing us on which gearsets you've compared?

[nando]

I have an E46 ring an pinion, it definitely doesnt fit. I'll have to dig up where i posted that, it must have been 2 years ago now.

I think it was a 3.25 or 3.15

[The Dark Side of Will]

"Fit" means... Doesn't bolt up to the E34 carrier?
Does bolt up, but E34 carrier with E46 gear won't fit with E46 pinion in E34 case?

[nando]

It would bolt to the carrier but its like 1/2" too thick, even if the pinion shaft was the same size it still wouldn't work.

[nando]

E34 on left, E46 on right:




it's hard to tell in the pic but the ring gear is definitely too thick for it to mesh up. you'd have to cut down the backside of it. the bolt pattern is standard BMW 168mm.

looking at it again the bearing on the pinion is the same but the output shaft is bigger. maybe there's enough room to machine the case to fit the E46 pinion and flange, dunno.

[The Dark Side of Will]

Still waiting for QC guy to get me the data package on the crossmember.

Also, ordered an inner and an outer ball joint from NAPA.
I'll pull a control arm, press the current joints out, measure the control arm carefully for redesign, press the new joints in and reinstall. Then I'll take one of the old joints and cut it apart on the band saw so that I can install the ball in the crossmember for QC guy to give me an exact coordinate for the pivot center of the ball joint and angle of the shank. Those are the only pieces of information that are hard to get about the crossmember.

With that info, I can get cracking designing a new crossmember and control arm setup.

As far as mount arms go, it also occurs to me that E53 mount arms are candidates in addition to E34 mount arms. I could also measure E39 mount arms; while those are less likely to work than E34 or E53, I should cover all the bases.

E34 M50
01	Supporting bracket left		1			11811136537	$31.86		
02	Supporting bracket right		1			11811135948	$31.86	

E34 M60
01	Supporting bracket left		1			22121702636	$49.83	
15	Supporting bracket		1			64551702640	$83.28

E39 M54
01	Engine support, left		1			22111092973	$31.87		
02	ENGINE SUPPORT RIGHT		1			22116752648	$31.87

E39 M62
01	CLIMATE COMPRESSOR SUPPORTING BRACKET		1			64551433562	$83.28	
07	Engine support, left		1		04/1997	22121745739	$67.38	
07	Engine support, left		1	04/1997		22121745739	$67.38

E53 M54
01	Supporting bracket left		1			22111096999	$50.24		
02	Supporting bracket right		1			22111097000	$46.00

E53 M62
01	CLIMATE COMPRESSOR SUPPORTING BRACKET		1			64557503477	$83.28	
06	Engine support, left		1			22116751345	$137.98

[The Dark Side of Will]

E34 on left, E46 on right:

Have calipers handy? What's the diameter and spline count of the splines on the E46 pinion?

[nando]

30mm OD, 27 teeth.

Haven't touched anything E30 related in like 2 months. Things should slow down this fall, I'd like to get my diffs built and finish rebuilding my transfercase..

[The Dark Side of Will]

Thanks!

30mm x 27 spline on a 3.5mm module. The largest module with a 90 degree face angle is 2.5, so those have a smaller face angle, which it looks like on the photos.

The driveshaft spline in the T-case is 35mm x 43 spline on a 2.5mm module, with a 90 degree face angle.

So one of the extended spline fittings could be made that had the front diff pinion splines and threaded shank on the end that normally gets welded into the driveshaft. This would allow the use of the E46 input flange at the T-case front output, which makes it easier to run a fixed yoke with u-jointed driveshaft.

[nando]

Yeah no problem, just had to remember where i put it!

[The Dark Side of Will]

Per the above, the pinion splines for a 188mm 4 bolt flange or a 210mm 4 bolt flange could also be cut, but the 168mm splines are probably smaller than those and easier to incorporate into existing design for the extended driveshaft spline fitting.

If the 168mm flange is strong enough at one end of the driveshaft, it's strong enough at the other end.

The only impediment is finding the part number for the E46 front diff input flange. (Either of us could check our flanges for it... you if you can find the flange and me if I take the flange off the diff)

[The Dark Side of Will]

Snagged a used control arm from a junk yard and knocked the ball joint apart today.

The CMM guy my dad works with has measured everything on the crossmember except the location of the ball joint pivot center. I popped the shank out of the ball joint and installed it lightly to the crossmember so that he could locate the center of the sphere and the lateral and longitudinal angles the shank makes with the mounting plane.

The press mandrel to support the control arm needs to have a minimum ID of 1.980. My dad and I used a sleeve with a 2.063 ID which worked fine.

The press mandrel to remove the ball joint needs to have a min ID of 1.400 and a max OD of 1.570... so it's fairly particular.