Axle question

[Trackrash]

Does anyone know what difference there is between the axles on a '71 and a '72?
I'm replacing the 901 in my '71 with a '72 915. I noticed the axle flanges are different. I thought the axles were the same? The flange on the right is the '71.

I would like to use the flanges that came with the 915 but am afraid they won't match my axles. FWIW the differentials are identical in both transmissions.

[Flieger]

The '71 uses a Type 911 transaxle. The '72 uses a Type 915 transaxle. I would think that is the reason the output flanges are different.

[rolls 912]

I had a pair lathe cut and then fusion welded with the newer flanges - and balanced. Worked a treat....

[Trackrash]

The '71 uses a Type 911 transaxle. The '72 uses a Type 915 transaxle. I would think that is the reason the output flanges are different.

That's what I originally thought. Believe it or not the differentials in both my '71 901 and '72 915 are identical. Even the same part number! So that's not it.

I think it has something to do with the CV joints. CV joints for '70 and '71 are NLA. But they are available for '72-'73!
Then confusingly there are replacement axles complete that fit 69-73.

So does any one know what the difference is between a 71 and 72 axle?

[m1franck]

I'm sure the output flanges where the CV bolts up are identical from your '71 911/01 trans to the '72 915. They should both be 108mm OD and use four 10mm bolts with 2 roll pins.

The CVs look like this?

[Trackrash]

Yes, both axle flanges are four bolt.

You will notice the difference in length in my photo above. That's what has me baffled.

I can only guess that there is something different in axle length or CV construction between the two years.

The part numbers on the flanges are:
'71 901 332 209 23
'72 915 332 209 01

Perhaps the flanges that I got with the '72 transmission are not the originals?

[m1franck]

With the output flanges installed in the transaxle what is the outside/side to side measurement from the face of one flange to the face of the other for the 911/01 compared to the 915 trans? My guess is one of these trans will be wider than the other.

I've recently purchased the new axle assemblies for my '71 911/01 trans. As you noted the PP website indicate these fit '69 to '73. When I compare the new axle assemblies to the old ones the differences are:

1. The CV thickness of the old 911/01 axles is more than the new replacement axles

2. When I measure the overall length of the old 911/01 axles and the new replacement axles, they are identical.

I've not yet installed these in the car yet, however, I do not foresee any issues.

[Flat6pac]

The thickness of the CV joint
40mm before 10/71
32mm after 10/71

Bruce

[Trackrash]

1. The CV thickness of the old 911/01 axles is more than the new replacement axles

2. When I measure the overall length of the old 911/01 axles and the new replacement axles, they are identical.

I suspected there must be a difference in the CV joint.

However my older 71 flanges are longer which would mean a wider transmission, needing a shorter axle or narrower CV joints. I'm going to take a closer look at my CVs when I get home today.

If you wouldn't mind could you measure the thickness of the CV joints you have?

Thanks,

Edit, Bruce, you were thinking ahead of me

[Nine9six]

Without any awareness regarding availability; why not try to source what you need from one of the Porsche dismantlers? Google Parts Heaven in Hayward CA.
P.S. Both flanges appear to have had bearings that overheated. Note the discoloration on both bearing surfaces.