A little help with a 1971 911/01 transmission

[xgrove]

As luck would have it I'm trying to mate two separate purchases: (1) a 1971 911/01 transmission and (2) a 1971 911T.

The 911T suffered some extreme elder abuse and came without engine or transmission. Due to the location of the homemade engine support gussets, it appears to have had either a Porsche 912/616 engine or a VW Type 1 or Type IV engine installed. This small fact may be important relative to the existing clutch cable which may not be original (although it appears to fit).

The transmission came without a throwout bearing (TOB) but other than that appears pretty normal.

My concern came when I went to replace/add the connector between the clutch cable and the TOB fork: Parts Heaven had what looked like the correct connector (57) (part not shown in my photograph) but because they didn't have one of these transmissions couldn't tell me what else I needed.

The issue they raised had to do with the boss on the mating surface (circled below) needing something to guide/hold the cable.

Any help understanding this and other issues I'm likely to face will be GREATLY appreciated.

Thanks,

RG

[mpetry]

I can help you with this one. The aft end of the "bourdon tube" (the black housing" is retained in the slot you see in the transmission casting at the mating surface. Part #62 is a little plastic thingie that had a reputation for failing. I made a replacement that worked very well, just a piece of brass with a hole and two "ears" on it.

I will post a pic of it - it's on my home computer. The nut behind it simply puts that part in tension. I think I used two nuts and locked them together.

Very easy fix.

Mark Petry
Bainbridge Island, WA

[Carrerax]

If your cable is wrong I have a good low mileage one ill sell for $25 shipped. They are kinda expensive new. Let me know.

[xgrove]

< Part #62 is a little plastic thingie ... >

Oh. So they sold me the wrong part (#57) or is #62 needed in addition?

RG

[mpetry]

I think 57 MAY be a later generation part. Does it have little "knobs" that match up with the detents in the release lever ?

Mark Petry
Bainbridge Island, WA

[xgrove]

The "articulating piece" seems to fit perfectly. In this picture the threaded end of the cable hasn't been pushed through the part. You notice however that it's still a considerable distance from the boss.

[hessel1974]

Hi,

For a 901 transmission you need the 57, 58 & 59 parts. You already have the articulated piece (57), but you need part 59 and a new clutch cable. Your current cable is not the correct one and will not work.

When you install the tranny to the engine, the TOF will move back (towards the front of the tranny) and the articulated piece will pull the fork in.

So new cable and Nr 59 and you should be good to go!

[Grady Clay]

OK, lets get you correctly situated and the right parts.

First, You have the wrong clutch cable and Bowden tube. The one for the ’70-’71 (#55 above) has a little lug on the end of the cable – no threads. The Bowden tube is captive on the cable and has a threaded portion toward the end past the white plastic sleeve. It uses two thin pattern nuts (#56) for adjusting and locking the adjustment.

You have the correct aftermarket ‘plastic piece’ (#57) made from aluminum.

I don’t see the retainer (#59) that holds the lug on the end of the cable in the slot/hole in the transmission ‘ear’.

The rubber (gummi) boot is typically unavailable. Find some other boot and make it work. That is a critical place to prevent road dirt.

I don’t see an image of the support ring that is part of the magnesium side cover. That ring must be in good condition.

There is also a steel support bracket that attached with two of the 8 mm studs of the nose-piece and intermediate plate.

On your chassis, inspect where the Bowden tube seats against the steel chassis. It is not uncommon to find a crack there.

On your clutch release fork, there is shiny mark where some aluminum has transferred. This is from the fork contacting the spinning pressure plate when fully operated. You can alleviate this issue by carefully reducing shimming under the pivot.

Be sure to clean, lube and test fit the new clutch disc on the input shaft splines.

Does your 911/01 have the rectangular boss under the differential for the type and transmission numbers? This should be a late ’71 version.

Best,
Grady

[xgrove]

So definitely a new cable and retainer.

(1) Transmission type/serial number = 911/01 - 7114534

(2) Support ring: Is the ring the part that guides the bowden tube towards the clutch fork connector?


(3) < shiny mark > Noted. You have a keen eye. I will read up on the issue as I spotted this topic on my journey through the "fork" threads of this forum.

(4) I hope this isn't the stupid question of the year but here goes: The clutch and pressure plate are both setup for 215 mm. The TOB for this transmission is 225 mm. Is the mating of these two "halves" impossible or will it just result in wear on the PP's fingers? Or more basically, can a pull type TOB work with a push type PP and clutch?

RG

[Matt Monson]

2. Your ring is hogged out. You probably want to find a new sidecover.
4. You can't mix and match the TO bearings.

[xgrove]

Thanks, Matt. It's been an interesting, if slightly painful, learning experience. Well on to Plan B.

RG