Is this going to be a problem?

[Guest Anonymous]

I put a 40% lsd 3.90 320 diff in my 72. After a number of failed attempts to get the car back together I got frustrated and went and bought the new 320 axles complete (with CV's). I replaced the outter CV with the '02 unit and bolted it up. I haven't put a ton of miles on it and those I have driven have been trouble free and noise free (at least from that area). Did I need to install spacers on this?

[Guest Anonymous]

(nt)

[Guest Anonymous]

I have no spacers and I am using the 320 half shaft or the 2002 half shaft, I forgot what we actually did, but the car is lowered 2 inches so the distance is reduced, unless it is up on a lift. I have been driving it like that no problem so far.

Michael

72 38/38

[Guest Anonymous]

mine are not on the car yet, but I did a lot of measuring when I did it. The length of the shafts, combined with the mounting point on the different joints seemed to add up to the little extra length that I needed.

[Guest Anonymous]

The most popular 2002 differential retrofit seems to be the 3.90:1 limited slip unit out of an '80-'83 320i with the 'S' package. The lower gearing helps acceleration, and the limited slip helps traction. A good addition for autocrossing or racing. The main problems with this retrofit is that the 320i differential is 13mm narrower between the output flanges, the bolt holes in the output flange are larger, and the rear covers are different. The rear cover can be swapped from a 2002 differential, but the width and bolt problem require more involvement. There are several options available to overcome this problem.

The easiest way to overcome this problem is to purchase modified output flanges from any of several aftermarket sources. These flanges have been modified with smaller bolt holes, and are thicker to make up for the differential width difference. The flanges simply pop out of the differential, and snap back in. You will probably have to return the old flanges as a core, however.

Another method that can be used is to mix and match half-shaft components. This requires the half-shafts from a '79-up 320i. Basically, the 320i half-shaft is used, but the outboard side CV joint is removed, and replaced with the old 2002 CV joint. This way, the inner joint matches the differential, the shaft is longer, and the outer joint matches the 2002 stub axle.

I personallly used the 02shafts with the spacers very easy solution.

[Guest Anonymous]

and clean the original '02 ones will work w/out spacers on 3.90 320i diffs. Consequently, we've had no problems on our '74 when we installed the LSD.

[Guest Anonymous]

i have a 3.90 LSD in my Inka with 02 half shafts and joints on both ends. The LSD had flanges that were small bolt size, but, the flanges did not have the "retention" ring, so they were able to freely move in and out of the diff, a total of almost an inch! I had bought 1/4 spacers with the longer bolts, the usual fix for a 3.90 LSD with a correct output flange. But those spacers did not correct the problem. I found another set of LSD output flanges that had the ring- that means you need a screwdriver to "pop" the flange out of the diff. That is the correct flange. BUT, those flanges have 10MM bif threaded holes, so you need 1 complete half shaft from a 1979 320 . That uses the big 10MM bolts on both ends. you then replace the inboard joint of your 02 half shafts with the 320 big bolt joint, and with some red locktight putit all together. Voila! no more gap, no more play- happy 02. here are the pics: i did the swap yesterday..... this is the overall pic of one side complete. Note: uutter joint is 02 with samll allen bolts and nuts onback side here is a close up of the inner transplanted 320 joint with the big allen bolts that do not have a back nut- they go into a threaded flange and are correct length..... here is a pic of my previous situation that was bad because of either PO ignorance, or unavailability of the correct components... so now i have zero gap, zero in/out play of diff flange, correct length, and a sense of relief. BTW: after the 320 half shaft was stripped of its ends, i ended up with a piece of solid metal that is very substantial. We have had a lot of discussion recentlyabout stub axle breakage and etc,.... well, i dont see the axle itself breaking, i think the failures have been in the outter joints: this is making me rething my zeal to get those upgrade billet stbs, because, the weakest link is still going to be present: it is the ends that fail. anyway, Barry- hope this helps you .