Transaxle design

[jkyle69]

Is their anyone on the forum that has experience of transaxle/transmission design? I am looking at the possibility of starting up a design project to design a transaxle with specific requirements in stages; I am looking for someone who can do this on a freelance basis and work with me to produce a project plan for staged design execution based around the specifications I have. Can anyone give me help/advice/contact for this at all?

[Doc Watson]

I've been looking at transaxle design for a little while now. I have a mechanical engineering degree and worked for a few years as a design engineer and project engineer in the paper industry which involved some huge gear trains. Im looking at T44's and ford toploader internals, although it has been said before that a Quaife Mk 2 6 speed is good for 750-800 HP and you can get it sequential. Its also expensive!!!!!

A replica T44 with a 427 side oiler in a mono chassis would be something special though.......

Doc Watson

[Jim Cowden]

Have had the same thoughts mainly because im a tight arse.
Cast a diff case that will take a ford 9" as there are 4 million ratios & cheap
$380Aust for cw & p.
Use available limited slip.
Plus you will never brake it.

Use a tremac there is on that handle about 600fp torque they have a selection of ratios.
Make a main shaft & cluster shaft (cluster is pinion).
Cluster is splined like a zf to slide all the gears on.
Mainshaft longer to go through diff housing.
Use all tremac selector hubs forks ect(cheaper)
The tremac case bolts to the diff housing.

Still a lot of work but very interesting project.
I have a tremac at work & everyday I look at that gearbox deep in thought.

Jim

[DBLDREW]

I agree with Jim with the idea of using standard off the shelf parts, but I would suggest going with a 8.8” r/p rather then the 9” r/p. Not that I think that going with a 9” would be a bad idea, it’s just that the 8.8” stuff is a bit cheaper, easier to come by and the strength of the 8.8” is still more then enough. There are 9 and 10 second cobra mustangs running the 8.8” and that is in a 3500lb car!

The one thing I would try to do is stay clear of Quaife if you need custom gears made. I think they are just a little over priced for my taste.

Just to compare a few products, if we look at the quaife torque biasing differential for the 8.8” rear end it will cost around $1300.00 compared to the Eaton Detroit Trutrac torque biasing differential will cost $435.00

If you want to upgrade your t-56 you can get a gearkit from g-force transmition that will handle over 800lb of torque for a little over $2000.00 or you can by a complete new trans for $4795.00 if you went with a new trans from Quaife you are looking at over $11,500.00!

So maybe contact g-force trans if you need some custom gear kits made here is a link…

http://www.gforcetransmissions.com/default.htm

[HILLY]

I like your idea Jim.
What do think the prototyping would cost if you were to include the cost of your own labour as well as the materials and subcontracted work??

[Jim Cowden]

Pete

I hadnt got around to cost I was still playing with in my head.

It would require a pattern for diff housing & ext housing.
For the experiment I would cut the back of the old one & plate it.

Use as much as you can without any mods.
Required remanufacture would be.

Main shaft on piece (no input output seperation)
I would contact the gearbox manufacturer of choice & see if they would be prepared to make the cluster shaft gears (exactly the same with a broached spline through the centre or blank)
Absolutly no reinventing the wheel.

That pritty much raps the box up.

The diff pinion your first stop would be the crown wheel & pinion manufacturer.

The diff case would require a tapered bearing to stop the gearbox being thrust of the diff housing by the pinion loads.
The bearing would nautralize that.
I would front load the diff & not from the side as it would reduce the case distortion.

Im not a trained engineer but for one its prob the cost of a ZF.
But for a few it might be half.

This is why you need to use existing parts as much as possible.
Once you have the pattern castings are as cheap as shit.

I get the feeling you are trying to trap me Pete.
Is that paint on my shoes Pete




l

[HILLY]

No traps Jim. I would not be smart enough for that!! I would probable just hit you with a big stick
The reason for the question was because I also have often thought of very similar but less detailed proposals that you have mentioned. Call me stupid but I like a challenge also. The problem is that I have is limited knowledge in this field and limited time at present to learn the ins and outs to come up with the design. The question of cost is more of curiosity than anything because without much of a brain strain you would quickly work out that it would be cheaper to just buy the ZF off the shelf and be on the road twelve months earlier with no teething problems. The only reason that I would pursue such a project would be for the challenge, experience and satisfaction of running the completed project in my own car. Obviously in your case you would be looking at ongoing business and ultimately a profitable product.
I dare say that I will do it one day, and as a one off I will probably just fabricate a box from AL plate and machine it from there. I even thought of a possible quick-change design just so it wasn’t too straightforward. But for now I will just concentrate on getting the car on the road with the little Audi.
And don’t walk that paint through the house Jim or you will be in the shit again.

[Jim Cowden]

I to wish to finish my car first before taking on a project.
I agree it is the challenge.
I might do some basic research & contact a few box manufacturers.
When we are both done building and still interested maybe a joint project.

The tremac I talked about that I have at work the owner turned up today he claims (I havnt checked his claim 600ft trq & 750hp it is good for)dont shoot me if that is wrong.
Cost new $3800 aust.
Its a good start to a low budjet.
Also its not very long.
I looked on the tremac site & they seem aprochable.
I did notice today that Subaru liberty auto has this set up.

Jkyle69 I apologize I feel like I have hijacked your thread sorry.

Jim

[HILLY]

Sounds like a good plan Jim.
I am sure that we will talk some more about this in trime.
Pop a photo of the tremac through if you have one.

[Richard Timte]

Jim,

I hope you have a lot of cash sitting around as I had the same thoughts. If you want to get the cost down (sales price) you need to produce around 100 units.

100 transaxle cast housings (50,000) for design and initial tooling and about 2000.00 each for a limited production run so 250,000.00

100 sets of shafts, seals etc. expect at last 1500.00 or more like 2000.00 for the shafts and such. so that is 150,000.00 to 200,000.00

100 front engine transmission for Donner gears and syncros 1500.00 each pr 150,000.00.

100 differential's 350.00 to 1,800.00 depending on style and source. 35,000.00 to 180,000.00

100 custom ring gears as it needs to be made with the same machine as making the shaft with the pinion gear at least 500.00 each or 50,000.00

So just to get you 100 transaxle the cost is going to be

250,000.00 +
150,000.00 +
150,000.00 +
100,000.00 +
50,000.00 =
700,000.00 or 7,000 each with no profit

I'm sure I forgot something but as you can see it takes a lot of capital to just produce 100 of these things and the price per is already 7,000.00 each with no profit.

[Richard O'Clery]

Some more related stuff from an earlier thread.

Richard, it looks like you are making an assumption that all design and engineering must be outsourced. You and I might have to do this, but some of the people on this forum would have many ways to reduce these costs. I expect that someone who could design make the patterns, and has a reasonably extensive home machining shop (mill, lathe etc) could build 5-10 units using all new components for around A$7,000 each, which is about a third of the price of a new Porsche transaxle.

While you would need to go large to make a profitable case for a full-time business, the right person could do this as a hobby and turn a couple of grand profit per unit. Of course the cost would go down a little for customers who are happy to use a 2nd hand gearbox/diff as the starting point.

Who wants to build a transaxle?

[BruceA]

I went down this track about 20 years ago. I had lots of ideas floating around on paper and in my head. Most of the design was to use a lot of existing parts eg: Ford 9" and Tremec or similar gear sets. All that is needed then is the in/out shafts and a case to be made (very simplified explanation there!!)

But lets put it this way. There are already thousands of diffs and gearbox units made for the automotive industry. More than 1 person out there knows how to design the things. Perhaps someone knows someone who does this for say, Ford, Honda, GM, Porsche etc etc. Pick their brains and run it by them as to what is involved and what can be done. Not limit oneself to the auto industry either, there is also the agriculture industry and heavy transport as well. Making the shafts wouldnt be a problem after the first one is done. Thats what CNC machines are for. Get one shaft right and every other is just a matter of the machine replicating the rest.
Even the casting isnt a problem. How about making up mould and have someone like Zeus Castings pop them out on contract? Better still, does someone know someone who works there, use their knowledge on this.
If you were to make 100 boxes the can be popped out rather quickly with current manufacturing processes. Ok, so you're saying "we need a die cast mould for the case". Well then, so be it. Someone out there must know who or where this can be done.
And - I think there would be more demand for a 'decent' box than just a run of 100. Probably world wide you could peddle off 1000 units to the mid engine crowd.
But it would have to have changable ratios, changeable diff ratio, changeable bellhousing to suit different engines, left/right gearchange etc etc.
Certainly not a pipe dream. And with the abundance of knowledge from people through this forum, how would it sound to have an 'global internet designed project' with product design and ideas from 15 countries!!!!?

[Ingvar Öhlund]

I have read on the ERA website that they produce reproduction T44 transmissons. Using original moulds to make the housing. I did not see any price though. We will probably see other making these gear boxes if the market is big enough

Ingvar

[Jim Cowden]

Since I posted I have asked someone in the manufacturing industry some questions on this because it interests me.

A few manufacturing processes that he explained would reduce some cost.
The comment by Richard about getting the pinion & ring gear made on the same machine so they match got me thinking.

If the end of the cluster or lay shaft at the diff end was machined down & a splined shaft fitted over it can be friction welded by spinning the 2 shafts at speed to make it as one.
If the bearing was replaced with a larger inside diameter to accommodate it.
Then a spline sleeve could be used to link the cluster shaft to the pinion.

The gear on the input shaft can also be used as the shaft can be cut off & the gear bored out & a sleeve friction welded to spin on the new main shaft.

Doing this has got it down to a main shaft & 2 modified existing gears.
Everything else remains the same.

As for the castings he explained that he would do a 3d model (cad) & he uses a process of powdered plastic & a laser ,the laser runs around in the powder melting it to form the die required & that can be done at reasonable cost (cheaper than a pattern maker).

This person makes diff products & is switched on; he didn’t see it as a major deal.
The other thought I had about bell housings was maybe if the diff housing face that bolts to it had some common stud patterns that allowed multie fit to existing bell housings?

Jim

[Trevor Booth]

Jim,
Not quite that simple,
In the event that the mainshaft is the driven shaft, the cluster set with pinion on one end has quite substantial bending loads induced by the CW & P set on top of the normal bending loads from the spur gear set. It is unlikely that any splined coupling would give sufficient rigidity to the Pinion.

In the event that the cluster is driven, a quill shaft from the clutch could via a splined coupling drive the cluster. however , you still need to support the cluster set. The bending loads from the pinion would then be on the mainshaft. The mainshaft gear set chosen would need to have a large enough ID to facilitate a mainshaft of adequate proportions.

An existing pinion gear may be able to be internally splined and shrunk onto a spline on the new mainshaft. The alternative is to make a new pinion gear.

You also would not finish up with a 1:1 top gear.


Polymer patterns from RP machines or 3D printers have a limited life span and not suited for production work. They are very good for somethings but not that. ie you can 3D model a ball bearing all assembled, have it 3D printed and get a functioning polymer ball bearing!!

Pattern making shops these days have 3 & 5 axis CNC mills and make a pattern direct from a 3D model. They are not expensive.

Not to dampen anyones enthusiasm, but, the cost would not be cheap and the end result may not provide a degree of longevity.

[aji]

You can also do what is done in Japan.

Take one apart, study it, make changes, put it back together with new part number and manufacture markings..

Than sell it without issue...LOL

[BruceA]

Why try and 'adapt' pinions to shafts and the like? Transmissions factories like Ford, Holden, Honda, etc are popping out gearboxes and parts at the rate of 1 every 30 seconds. Ok, so they have several machines to do the work, but the point is, instead of adapting a secondary shaft, just make a new one! Thats what CNC machines are for.

As for the case, how about this for an idea.
Use an existing transaxle case. eg: a Porsche or ZF or similar. Then perhaps just make a small mod to get around copyrights if necessary, then use that case as the start for the making of a die.
OR someone with good influential speaking skills, convince Mr Porsche to sell them 1000 cases only from their gearbox factory and we can put our own internals in it!

[brett w]

Porsche buys all of their gear boxes from Getrag or Aisin Warner. I am sure you could contact these companies to make a box that would meet the requirements or perhaps buy a bulk number of the boxes we need.

[Tye GT40]

Hi guys,

A project for a T44 is started in Sweden. Please follow the link below.

T44 Gearbox soon in production

To be able to see the pictures you have to register. It is worth the trouble!

Regards
Henrik Smedberg

[John W]

For those that can't see the link, it is from Goran at GOX. He is trying to fill an order book before starting the first production run. You need to contact him for prices.

The ERA one last time I spoke with them was in the order of $30k...