915 Output flanges LSD vs Open ????

[Russ in VA]

I am trying to finish up my tranny swap. I have a worn out limited slip trans that came out of the car and I am replacing with a rebuilt open diff trans. I went to hook up the axles, and found that the output flanges on the "new" open diff trans are larger and require larger bolts than the old LSD unit. Can I just swap the flanges from my old unit over? I read something about fine splines vs. coarse splines on another thread that has me worried that this won't work. What is the quickest cheapest solution to this problem?

"new" open transaxle came out of a Carerra, I believe an 84 but it could have been a later model. Numbers on case are: 915/73 74G 07462 Bolt circle is approx 95mm and OD of flange is approx 110mm

"old" LSD trans is from my 84 Carerra Numbers on case are: 915/68 12 74E00791 Bolt circle is approx 85mm and OD is approx 100mm

Thanks,

Russ

[addictionMS]

the new output flanges are 930 style, the old ones are original, if you have the original CV style which mate to the smaller flanges, you can simply swap the original for the 930, if interested I have a set of original style I woul dlove to swap for 930 style, let me know.

Jim

[Russ in VA]

If they'll bolt right in, I'll just swap out my own. I read something about fine vs. coarse spline. Is that not applicable here?

I will be selling the old trans as a core. The flanges will go with it unless the buyer does not want them. What are they worth separately? (I have offers of $500 and $700 for the complete core.)

[beepbeep]

Later 109mm Carrera shafts are stronger and cheaper to boot.

I suggest you to keep 930-style flanges on tranny and swap buth shafts instead. It's bolt-on. Then you can sell core tranny with it's original flanges.

This way you will get new/stronger shafts and lower prices in case you need to change them.

[ChrisBennet]

When you say the original trqansmission was "worn out" do you mean it was broken or just in need of a rebuild?

The axle change happend in mid '85.
I agree with beepbeep.
-Chris

[H20911]

you are probably dealing with something like this


I agree with the others on this change the joint or axles

[ChrisBennet]

Just to clarify. The 85.5-89 Carrera flange (105mm) will pop right into your '84 915.
-Chris

[Russ in VA]

Thanks everyone! For now, I have my old flanges installed in my new trans and everything is working great (It is SO nice to be able to shift freely again!). I think I will sell the LSD core w/o flanges so that when I need new CV's/axles I can upgrade AND save money! Just to besure I understand this correctly, the axles with the larger bolt circle at the output flanges will bolt right up to my hubs meaning that the hub end did not change when the flanges got larger???

To answer Chris's question, when I say worn out I mean still drivable BUT noisy at all times proportionate to road speed, shift lever moved about 1.5" when getting on and off throttle in 1st,2nd or 5th gear, sometimes hard to get into 4th but not a synchro type hard just very stiff did not want to go in, did not want to go into first but again not a grinding type did-not-want to go in but rather a physically would not go in type thing, fairly large chuncks on the drain plug and leaking profusely from the front of the tranny somewhere. Also, 3rd gear synchro was getting slow and speedo read about 3/8ths of road speed but is now miraculously fixed with the "new" trans indicating that some of the speedo sensors magnets had fallen off (perhaps some of the chunks I found on the drain plug?). Have had several folks more knowlegable than me diagnose my problems as worn main shaft or thrust shaft bearings. 150k miles on tranny.

[john walker's workshop]

just be sure that the length of the section that inserts into the diff is the same as what came out. compare, tip of the splines to bottom of the raised seal ring.