904 LSD open heart surgery

[ajwans]

Actually it was my stupidity, not molykote. When measuring the cover plate extrusion I added 0.025", I guess I counted the gradations wrong. This gives enough room in the housing for even the longest acceptable clutch pack installed length.

andy

[68S_SK2]

Hello,
How could I find out the slip ratio (50% or 75%) without disassembling the slip.

Next question:
I have 2 different NOS LSD's for Nadella flanges.
One is the early 904 style, the other LSD has the later style 1969-73 differential axles and bevel pinions but also for Nadella flanges. Both housings have the same ZF number. Has anyone seen this before?
I think ZF somewhen switched the housing and the interior, but both would fit into a SWB gearbox.
Which one is more reliable the early 904 style or the later style? I think the later style is more prone to error or?

left LSD: early 904 housing style with Nadella flanges______________________right LSD: later housing style with Nadella flanges


Thank you for your help.

Best regards
Claudius

[Jon B]

One is the early 904 style, the other LSD has the later style 1969-73 differential axles and bevel pinions but also for Nadella flanges.
Both housings have the same ZF number...

Claudius, those are very nice :-)
They should be opened, cleaned and re-lubricated before using anyway.

Do they both have 45 mm bearing journals? If so, they're pre-'70 differentials for aluminum transmission housings.
Differentials for magnesium transmission housings from '69-on have 50 mm bearing journals.

What are the numbers on the differentials?





Jon B.
Vista, CA

[68S_SK2]

Hi Jon,
Thank you for joining in!
Both have 45mm bearing journals and both are 4061 004 004 marked.
I'm not planning to use them, but I want to understand the difference in between both and when the interior was changed? I saw several of the later style with broken teeth. I also know, that some of the early housings differ inside: Some housings do have the 4 slots only other housings have an enlargement for the pressure ring for little radial rotation.
It's a nice booklet, but there is not much explanation given, I have the German Version.

What do you know about it, Jon?
Best regards
Claudius

[Jon B]

I'm not planning to use them, but I want to understand the difference in between both and when the interior was changed?

Claudius, you can open those up and document the differences for us!

There were a few versions of this differential. It was used in the 911 until '69, but also in the 904, 906, 907 and 910 transmissions.
I think production continued beyond '69, for replacement units.

The pre-'67 004 differentials had only 4 friction discs- 2 per side- so could not be arranged for 75% anti-slip effectiveness.
From '67 they had 6 friction discs, so it was just a matter of the disc arrangement.

Jon B.
Vista, CA

[68S_SK2]

Here are the obvious exterior differences:




Here are 2 used early style/small eyelet type ZF 4061 004 004 LSD with different interior:
One has notches for the pressure ring the otherone not.



Any explanations for it?

Thank you.

Best regards
Claudius

[gled49]

I’d guess the one housing is damaged, not sure how, but damaged. G

[68S_SK2]

Sorry, no, it is defenitely accurately milled on all 4 sides the same configuration.

[Jon B]

Here are the obvious exterior differences...

OK, it's just after 9am in California and I'm back.

I'll open the 004 ZF I have here and compare it to the examples in your pictures.
The lack of visible "axles" in one might be a slight re-design, in later versions, to decrease the "eyelet" blockage.

Jon B.
Vista, CA

[Jon B]

Claudius,

The 004 ZF here has 22 mm "eyelets", 6 friction discs- 3 per side- and the "axles" align with the eyelets.
Mine can only be assembled with the axles aligned with the eyelets.
It doesn't have the large, machined notches as in your example, but it does have very slight notches in the same place from wear.

I don't think the housing cover screws were normally yellow zinc plated... how are the screw heads marked?

Jon B.
Vista, CA