901 Transmission

[Forssling]

Hi All, I'm restoring a -71T which I bought in crates. This is the transmission I got. There are some flat areas at the bottom front of the case. They both have two holes in them.

What is this for? Is my transmission case modified?

Please help shed some light over this!

Jörgen Forssling
Gothenburg
SWEDEN

[MBEngineering]

HI Jörgen

the gearbox looks like it has been fitted to a VW Beetle, as the Rev light switch has been chopped, and there are large studs in the end casing.

is the speedo drive still in the end case?

the holes in the bellhousing are to mount the box in the beetle gearbox support.

I would remove the drive shaft flanges from the box and take off the diff side plate, to inspect the pinion, also remove the end case and inspect 1st gear dog teeth

regards mike

[Forssling]

Thanks Mike, for your input.

The speedo gear are still in. Can you clarify "there are large studs in the end casing" and "Rev light switch has been chopped".

So if I weld the holes for the beetle gearbox support I will be OK with this case you think? Is it aluminium or magnesium?

Will get back regarding inspection when I clean it up some more.

Thanks a bunch!

//Jörgen

[Trackrash]

The case is magnesium. The clutch release arm and cable are unique to this trans.

Post a picture of the other side of the trans and inside the clutch area.

If you plan on using the '70-'71 clutch, cable, and other parts you will need to have the three parts shown by the arrows.

[MBEngineering]

HI Jörgen

the Rev light switch should look like this



and the end case, like this,



this is the casing with no holes, it is from a 914, converted to fit a 911



the case is magnesium, 911/01 box should have a gear set of ;

1st A 11:34
2nd GA 18:32
3rd O 23:28
4th V 27:25
5th ZA 29:22

with a 7:31 CWP

unless some one has been in there and changed things round

has the clutch arm pivot in the bell-housing been moved/changed, as some times the ratio is not correct for the Beetle and the clutch will not work correctly

regards mike

[Forssling]

Thanks Gordon and Mike for valuable info!

I will check my trans and get additional photos when I get home.

Meanwhile, can I ask you Gordon about your pic with the arrows:

Top arrow, is that a separate part or integrated to the diff cover?

Bottom arrow, same there, a separate part or integrated to the case?

I have searched for images but find very few with these details. Can't seem to find these details in the PET either. Can you post some additional images?

KR//Jörgen

[Mark Henry]

I agree it was in a bug, I have a 911/901 with 914/4 gears in my '67 bug with a 2.6L T4 engine.

[Forssling]

Hi All!
I got some additional photos yesterday.

I have now seen that the both parts I'm missing is integrated.

My plan is, for the case, fabricate a mount in aluminium and bolt it using the two existing holes. Weld the two holes on the other side.

Try to locate a diff cover with the cable guide intact. Or fabricate it and use the bolt below to fasten it.

I need to find a drawing of the bell housing or find someone to stencil the clutch wire fixture. Anyone here that can help?

Regarding the gears, is there a way to determine what gears I have shifting gears and count revolutions?

ps. I've got the clutch fork. The yellow bolt just put there temporarily.

Thanks for all your support!

//Jörgen

[Trackrash]

Looks like you can make it work. Unfortunately my 901 is long gone, but hopefully someone will chime in with the measurements you need.

If you get the clutch cable with the end pieces that will help you get things aligned correctly.

Thankfully the release arm pivot mount is still good.

[Forssling]

Thanks Gordon! These days you've got to work with what you have. I have a new cable and end piece so that will help as you say.

What do you think about finding out what gears I have? Got any ideas on that?

Cheers//Jörgen

[Trackrash]

Have you pulled off the side plate yet to inspect the ring and pinion? I would do that before commiting to this trans. Not hard to do, and if the R&P is good, most likely the trans is usable.

As far as the ratios go, I would guess they are the stock 911 gears. Who would change the gears for a VW? But who knows.

1st A 11:34
2nd GA 18:32
3rd O 23:28
4th V 27:25
5th ZA 29:22

You should try to keep your side plate. If you replace it with one from another trans you will have to check and posslby reset your R&P, which is a PIA.

You will also need the cable guide (clamp) and the throttle crank. Here is a picture.

[Forssling]

Gordon, I've got the throttle crank but not the cable guide yet. It is a hard to find item and NLA from Porsche.

OK, so I pull the side plate and there is the ring and pinion. What do I look for? Obvious damage? Something else? Appreciate you taking your time to educate me.

//Jörgen

[Trackrash]

I imagine it would not be hard to fab a cable guide, if you can't find one.

Here is a thread showing a damaged pinion gear. Metal bits in 915 oil

You might want to take some pictures of yours and post it here if you have doubts as to its condition.

[oldie44]

Attached is a picture of a clutch cable guide that bolts to the side cover. Another picture shows the welding jig used to align the parts. I can send you a guide for €50 including shipping to Portugal but you need to work through a complete solution first.
You have another problem though in that the clutch cable fixed point has been sawed off. Your clutch won't work without it. See the pictures.

[Mark Henry]

Originally Posted by Trackrash

As far as the ratios go, I would guess they are the stock 911 gears. Who would change the gears for a VW? But who knows.

I did, my 911/901 in my '67 T4 conversion bug has stock 914/4 gearing.
My 3.0 914/6 (again conversion) has a,f,o,x and a flipped HB 5th.

Only way to really know is to remove the stack.

[RWebb]

or spin things in each gear & count the turns...

BTW, the 1970-71 cars take a typ 911 trans, not really a 901

[Forssling]

Originally Posted by oldie44

Attached is a picture of a clutch cable guide that bolts to the side cover. Another picture shows the welding jig used to align the parts. I can send you a guide for €50 including shipping to Portugal but you need to work through a complete solution first.
You have another problem though in that the clutch cable fixed point has been sawed off. Your clutch won't work without it. See the pictures.

Thanks for your offer. I'll get back to you if I need the jig. I'm working out a template for the cable fix point and are going to get it fabricated. The images helps a lot.

//Jörgen

[Mark Henry]

Originally Posted by RWebb

or spin things in each gear & count the turns...

BTW, the 1970-71 cars take a typ 911 trans, not really a 901

Nit picking and I do it for clarity. Really don't care, I've rebuilt way more than you have and I'll still call it a 911/901.
901, 914, 911 are all base 901 transmissions and 96% of the part # start with 901.

[RWebb]

not "Nit picking " if you need to ID something to someone else

but I'm sorry to hear about your parasite infestation

[Matt Monson]

Put a 901 clutch in a 911 and you’ll care. Or order a 901 lsd for your 911 box and wonder why the bearings and axle flanges don’t fit. I’ve learned not to correct every single post here about it being wrong. However when someone says ,”how do I fit this 901 in my car?” It is importsnt that they understand the differences.