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Posted by: ctc911ctc Sep 3 2020, 06:28 PM

'74, 2.0 Barn Find - ~22K miles

I have been posting and working on this car for 2 years - I have it running and performing well - about an 80 point driver.

Decided that the 1st to 2nd transition needed work as well as a few oil leaks so I dropped the engine and started to rebuild the tranny.

I watched the Dr. Evil video 100 times - better than anything on Netflix

But I found something that is flummoxing the 914World.



I replaced the Dog Teeth and the Synch rings on 1st and second gear. When I opened second gear I found that the Anchor Block was broken into 3 pieces. HHHhhhhmmmm!

Soooo, i ordered a new part from my favorite vendor and received the part above (the one that is NOT broken) and it is too big. However, this is the correct part as per all of the documentation.

As a Sanity Check, I opened up 3rd gear and the same SMALL anchor block is in 3rd as well. Also in 4th and 5th!

My questions to the 914World are:

1. have you seen this before? Calling Dr. Evil @Dr_Evil
2. What might cause one of these to crack into 3 pieces?
3. Might this be the PO putting in the car 911 parts? (these small anchors are found within 911s I am told)

Thank you fellow teeners.....

Posted by: ctc911ctc Sep 4 2020, 08:02 AM

So far 127 people have read this post and not one has responded.

Seems that my Tranny is a Red Herring of the 914 fleet!

My guess is that they ran out of parts and reverted to older bins ( smaller anchors and larger braking bands) to meet the quota?

Posted by: Mark Henry Sep 4 2020, 11:40 AM

Dr Evil has a lot on his plate and isn't here as much, but he's on FB, Evilwerks LLC.

Posted by: 914werke Sep 4 2020, 12:12 PM

IIUC Looks like you have a mix of early & late brake bands & blocks.
Pretty sure early are shorter/smaller & longer bands, later are longer/bigger blocks & shorter bands
I have a Pic somewhere that helps ID
As long as you dont mix the two ON a gear pak it will work fine.
As to what caused it to break...?

Posted by: dr914@autoatlanta.com Sep 4 2020, 12:13 PM

porsche superseded the part to the longer one and also calls for shorter corresponding anchor bands.

Posted by: Olympic 914 Sep 4 2020, 05:45 PM

Dr. Evil did my trans and found a mixture of the short and long on different gears. My car is an early '73

Posted by: Dr Evil Sep 4 2020, 09:04 PM

901 had long bands and a short base block from inception through 1972. In 1973 they changed to short bands and the wider base block you pictured. The bands you have are definitely the long ones that use the destroyed short blocks. I can send you short, long, big, small, whatever you need.

Posted by: Dr Evil Sep 5 2020, 04:19 PM

Since I’m out in the shop today I thought I’d snap some pics to give example of what I was talking about.


Attached thumbnail(s)

Posted by: Dr Evil Sep 5 2020, 04:20 PM

Bands


Attached thumbnail(s)

Posted by: ctc911ctc Sep 5 2020, 07:49 PM

This is terrific,

Thank you Dr. E!

Any idea why the design change?

The date on my tranny is 11/26/72 the car is a '74

My impression is the long bands and short anchors are EARLY 69/70 production. and then there was a change to the longer anchor and the shorter bands?

Practically - from my perspective - the anchors break so they made them bigger ??

Thank you,

Posted by: Dr Evil Sep 8 2020, 11:31 AM

Internals of your box may be sketchy due to late year. I dont know if they transition gradually over a week and use up inventory, or if they mix it up until all old stock on hand is used up. Maybe someone else assembles the gear sets and it depends on whose bench it came from.

The change makes sense. The bands and block work such that the synchro band pushes against the top blocks nub. That nub slides the top block left or right depending on up or down shifting. The block then pushes the energizer band (the internal bands)_into the base block and forces it outward to firm up the synchro band keeping it from collapsing. The longer bands would be more flimsy, the short ones more stout. However, the long blocks crack as well sometimes and its imperative that they are cleaned and inspected as I have seen small cracks that were not obvious on cursory inspection. The purpose of the energizer band firming up the synchro band is to lock the synchro band into the slider. You will notice a groove in the center of the sliders that matches the crown on the synchro band. The synchro band will not lock into place if the block is broken so you will pop out of gear. Also, getting into gear can be a pain as the synchro band will just collapse. Sometimes, the block/band will break in such a way as to force the synchro band to be firmed up with the broken and jammed parts and you wont get a grind, usually, you will just get no gear engagement as the slider cannot slide over the expanded synchro band. Easier to show, as on the DVD, than to write if you are visual like me.