901 gearbox driveshaft question

[Mawa]

Hi everyone. I have been quite challenged no by my 901 gearbox, first first the fork was not the most common option so the kit for the clutch did not match.




Now I am suffering quite a bit with the driveshaft. And the little driveshaft connection in the gearbox looks tiny like the one for 914

I have upload 2 pics from the drivetrain the part coming on the car and the one coming on the gearbox







I have tried to find the one in the driveshaft without success. Which one should I change and which part should fit gearbox and driveshaft?

I base my conclusions in the following link.

https://californiamotorsports.net/pages/porsche-901-transaxle-specification

Thanks a lot.
Al

[jpnovak]

The box in the picture looks like a 70-71 911/01. What are the numbers stamped in the boss under the differential housing? This will confirm what you have.

The axle flanges should be 108mm with 4 M10 bolts and 2 roll pins (unthreaded). This is the standard axle for 70-73 911s.

Yes, the clutch fork will appear backwards. The clutch is a pull clutch with a push cable. Strange it is. It requires a special clutch/pressure plate/ throwout bearing and cable setup. You want the 70-71 clutch parts to fit it.

What car is this going in?

[Trackrash]

Looks like a strange mix of parts. Those axles look to be later fine spline drive flanges, but maybe it is just the picture.

Show us a picture of the rear of the trans where the clutch release arm pivots and the number on the bottom.

Does the trans have a limited slip?

[Mawa]

Originally Posted by jpnovak

The box in the picture looks like a 70-71 911/01. What are the numbers stamped in the boss under the differential housing? This will confirm what you have.

The axle flanges should be 108mm with 4 M10 bolts and 2 roll pins (unthreaded). This is the standard axle for 70-73 911s.

Yes, the clutch fork will appear backwards. The clutch is a pull clutch with a push cable. Strange it is. It requires a special clutch/pressure plate/ throwout bearing and cable setup. You want the 70-71 clutch parts to fit it.

What car is this going in?

Right now the car is getting painted and I cannot take that pic with Covid19 restrictions
But this is the set up for the clutch


I can confirm that the part of the gearbox has 4 screws and 2 roll pins. However, there are different size of driveshaft with that configurations; mine is the small one. I already bought and returned one new kit that did not fit with 4 screws and 2 roll pins.

It is going in to a roller 911E that we have put a 2.7 engine with carburetors. This rollover used to race with a 2.8 engine and I guess with a G50 transmission.

The car is the silver one in the pic


The post of the car I here https://forums.pelicanparts.com/porsche-911-technical-forum/1042687-lightweight-911-rs-2-7-over-911e-72-shell.html

[Mawa]

Originally Posted by Trackrash

Looks like a strange mix of parts. Those axles look to be later fine spline drive flanges, but maybe it is just the picture.

Show us a picture of the rear of the trans where the clutch release arm pivots and the number on the bottom.

Does the trans have a limited slip?

I believe it does not have lsd.
The thing is that I bought a roller and these axles came with the car and before it had 100% a different gearbox

[Trackrash]

Here are the flanges that Porsche used. If the car had a different trans before, it may have been that the flanges in the suspension arms were changed.

The trans is a 901/911 for a '70-'71 only. You will need the '70-71 only disc, clutch cable and throw out bearing.

That trans used a course spline drive shaft output flange with the 108mm 4 bolt and two pins. However, I have read and maybe someone can chime in, that some of the old limited slips used a special drive flange. So confirm a limited slip.

This thread has some good info. http://forums.pelicanparts.com/porsche-911-technical-forum/591069-cv-joint-axle-half-shaft-compatibility.html

[Mawa]

Originally Posted by Trackrash

Here are the flanges that Porsche used. If the car had a different trans before, it may have been that the flanges in the suspension arms were changed.

The trans is a 901/911 for a '70-'71 only. You will need the '70-71 only disc, clutch cable and throw out bearing.

That trans used a course spline drive shaft output flange with the 108mm 4 bolt and two pins. However, I have read and maybe someone can chime in, that some of the old limited slips used a special drive flange. So confirm a limited slip.

This thread has some good info. http://forums.pelicanparts.com/porsche-911-technical-forum/591069-cv-joint-axle-half-shaft-compatibility.html

Thanks, to be honest is awesome to find a lsd gearbox without knowing about it.

Regarding the clutch, disc, an throughout bearing is solved and mounted on the car. I just posted the photo to further limit the gearbox types. The cable I plan to change it (not yet done).

To be honest regarding the table I see 108mm and as the photos shows mine is much less.

Thanks for the threat suggestion. In his case was pretty same size with the G50
Al

[Trackrash]

It looks like someone has put an older drive flange in the transmission. It looks like the '68 style?

The replacement axle is for a newer car, it looks like one for an SC? So the bolts match up with the trans, but won't work due to the end cap? Or is that axle for G50?

[jpnovak]

What flanges are on the trailing arms? Do they match the transmission?

Transmission should have 108mm 4 bolt-2 pin flanges.

First step is to match the drive flange on the trailing arm.

The flange on the trailing arm can be matched if you have the smaller 100mm -6 bolt flanges. The output flanges on that particular transmission can not be changed.

The picture of the CV half shaft with flanges will not fit the transmission in the picture.

BTW, if the car was setup for a G50, then the transmission you show may/may not mount in the car. A G50 has a very different mounting system which requires cutting and moving the torsion tube. Unless it was a shortened G50.

You need to check carefully that the original structure is still present under the tub.

[Matt Monson]

Based on what I have read so far, I believe this gearbox is a 1969 901 gearbox. It is a push type, like the aluminum 901 gearboxes instead of pull type as found on 1970-71 type 911 and 915. It should have 108mm flanges on it, but 100mm 914 flanges bolt right up to it. In fact, it could even be a 914 gearbox that someone converted to use in a 911 by flipping the ring gear over to the other side.

Are there any type numbers still on the gearbox? There's a rib on the bottom of it that will have both the type number and serial number. In absence of that, get us some of the casting numbers off of it. There will also be a little circle on the side of the main case with a production date in it.

Please further explain the clutch situation you've battled with? Or better yet, take a picture straight into the bellhousing showing the assembly so we can tell.

[Matt Monson]

Oh, and here's an old thread loaded with Grady Clay info that might help you out.

http://forums.pelicanparts.com/porsche-911-technical-forum/166598-clutch-cable-70-71-901-a.html

[jpnovak]

But Matt, Is that the Bowden Cable guide attached to the intermediate plate in first picture? That's why I think its 911/01.

[Matt Monson]

Originally Posted by jpnovak

But Matt, Is that the Bowden Cable guide attached to the intermediate plate in first picture? That's why I think its 911/01.

I don't trust anything on what appears to be a "bitsa" gearbox. And the details he's provided are quite vague. That's why I'm asking for more info.

[Jon B]

It's a 70/71 911 transmission set up for a pull-clutch.

The clutch lever hook is in a pull-clutch direction.
The attachment for the cable end is clearly visible on the bellhousing.

The axle flange is from a 914.

[Matt Monson]

Originally Posted by Mawa

I have been quite challenged no by my 901 gearbox, first first the fork was not the most common option so the kit for the clutch did not match.l

This is what led me to my comment that was contrary to what the pictures show. The '69 clutch configuration is what I would consider "not the most common" version. I thought maybe he was trying to convert it over to the later style by moving the pivot ball, as many have done over the years.

He clearly shows the PET for the 70-71, but again, explanations are spotty. He doesn't really tell us what his clutch problem was and how he fixed it.

I agree, it presents as a 70-71. Based on both the bowden tube and fork. And then it has the 914 flanges. That's why I asked a bunch of questions instead of assuming anything we were looking at was definitive on it's own.

[spyerx]

So...fwiw i had a very well know porsche tech (D.....) under my car look in bewilderment at my trans when he asked 3x if it was a 71... and 911/01 trans type While adjusting clutch. Yes, of course i said. In a very think German accent “what idiot back dated the cable/fork actuation?” He says. I just shrugged. He was able to adjust it out to stop the 3rd gear slipping i had...

Looking closer, yeah. Push setup. Found pics of restoration and off the car and i guess the p/o reused the parts as they look newer. But. It’s got an early clutch actuation. The bell housing was drilled and in the restoration pics can see the pivot in the push location. Guess they didn’t change it back....

I will be changing it back to a pull setup shortly. The pull forks are $

Anyway. .... sins of the past.

[Matt Monson]

Spyrex, I may have a used one. You’ve got my email.

[Trackrash]

I have my old '71 clutch arm which I am never using, let me know if you need it.

[Mawa]

Originally Posted by Matt Monson

This is what led me to my comment that was contrary to what the pictures show. The '69 clutch configuration is what I would consider "not the most common" version. I thought maybe he was trying to convert it over to the later style by moving the pivot ball, as many have done over the years.

He clearly shows the PET for the 70-71, but again, explanations are spotty. He doesn't really tell us what his clutch problem was and how he fixed it.

I agree, it presents as a 70-71. Based on both the bowden tube and fork. And then it has the 914 flanges. That's why I asked a bunch of questions instead of assuming anything we were looking at was definitive on it's own.

When I meant that is that the bearing from the clutch kit I bought did not much the fork and it toke me some time to find it. I am not a mechanic neither a Porsche expert this is a hobbie that just went out of hands

The standard type of clutch bearing I needed to replace with the part 8 of the pic.

[Mawa]

Hi all, much appreciated all your help

At this point with Covid19 we are in quarantine so I cannnot got to the paint shop and see or take pics of the gearbox more than the ones I already had.

When I bought the gearbox the reference from the seller was 901.301.301.2R and 301.301.101.0R

I believe I have a 70 to 71 gearbox as Jon and others have said is a 70-71.
Does anybody know the flange part number that should be bolt in to the gearbox as standard so I can change and will fit without braking it?