Custom transaxle

Hi guys ....this is my first theard and thought this would be a good place to get some feed back on my trans axle build. I'm in the early stages of building a trans axle from Nissan Patrol diff and gearbox. the reason for the choice of parts is 2 fold, 1st I had the parts lying around so it was cheap start, 2nd I need a trans that will handle Big Block HP and Torque as I intend to wrapp it in a Can-Am replica. I have been running this stuff in offroad racing and 4x4 challenge events with 600hp chev through it and you canot break it. the plan is to build a self contained diff carrier with the Pinion and the spigot shaft mounted in it so that it can be mated to the G/Box with yoke type splines driving through the Lay shaft and back through the tail shaft. The G/Box is normaly a 5 speed but for ease of aplication on this first atempt I have removed 5th gear so as to utilize the spline on the leyshaft for the spigot shaft. the other thing is in normal use the Leyshaft is under driven and when driven throught the Leyshaft this becomes overdriven and you end up with a top gear thats way to high. This way I now have ratios of 1st - 3.25 2nd - 2.00 3rd - 1.25 4th 0.75. the diff ratios avalible off the shelf are 3.54 - 4.88 just as a matter off interest with 4.1 diff at 6400rpm and 27" tyres gives you a speed of 203mph about the same as the cars of the day. At this point I have made the moulds for the carrier and the side plates and intend to have the alloy casings done in the next couple of months I also will start the rear uprights and hubs this time home and will post some phtos as the suff comes to life. I look forward to your advice and thoughts.

Cheers Leon
 
Hi guys, I thought I would revamp this thread I started way back and show the progress I have made on my transaxle. I have moved this from my M20 build log to see if I can get a bit more feed back as a Lot of you GT40 guys read this section and don't always go to the Can-Am section.
So to recap whats done so far, I have made the casing moulds from MDF and 8mm ply and I'm using Nissan gears and Diff. The gearbox will be a 4 spd and run the Pinion via a third shaft driven with QC gears in the rear section the Nissan selector forks are retained and mouted on the right side of the casing for ease of a right hand gear shift. the Diff is mounted in the side plates and will be shimed to set back lash. the spigot shaft will drive through the Ley shaft,
The shaft centre's are 4"/100mm and the the need to go to a third shaft was because the diff centre is too big to get the spigot shaft under it with the 25mm offset of the pinion. It does have its advantages in that I can easly change the final drive ratio with the Drop gear set up. I will post the photos so far and you can see where I'm headed.
 

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The first 2 Photos are the Skeleton of the casing cut from MDF, I have gone for a "Spit Case" design to make the casting process easier as there will be no need for Floating cores. The alloy I'm planning on using is the same 5008 that I have cast MY uprights with (See "M20dreaming" build log) The next thig was to give it some body and start to fill the spaces, the next Phtos show how the "Diff" and "Gears" are packaged and also how the selector fork will be fitted.
 
OK, the next step was to fit the Ley shaft and main shaft into the wooden mould to see how they would fit and relate to the housing, the selector fork set up was then fitted and it was tryed to see if it would select gears?? so far so good. AS you can see from these photo's there is the long tail shaft still sticking out the back with the ley shaft below it. The ley shaft will be used to drive an oil pump and the tail shaft will be cut off leaving the spline which will be used to drive the drop gears to the Pinion shaft (not yet fitted) The old spigot shaft at the front is also removed and a new spigot shaft will be made and mated to the ley shaft. Since these pics, I have also fitted the reverse idler gear. Once I'm happy with the set up I will finish the moulds off with filler and Polyurathene and have them cast then the custom made shafts (Spigot, Pinion) will be made and the precise job of machining the finished housing's will be done. My aim to keep as much "Off the Shelf" as possible is going OK with only the pinion extension shaft and Spigot shaft having to be custom made and also the QC drop gears will need to be made if I change from the ratio that I have at Present which gives me a 15% OD to the 4.1 Ring/Pinion. So that is it at present please feel free to comment and give ideas. Cheers Leonmac.
 

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For some reason I don't know of, the Photos have come in a different format and don't enlarge. The first Photo was fine but after that it went wrong, sorry. I just worked it out and will try to fix. Leonmac
 
You are building your own transaxle? WOW. I'm impressed, seriously. Please don't cast your own engine block, forge your own crankshaft and pistons too. PLEASE :)
 
Jimbo......I have already cast my own uprights and I'm seriously looking at casting my own wheels for this project, What can I say, Its a Kiwi thing. I think half the time we do it just because people tell us we can't and the other half is "need's must" In my case, I need a trans that can handle 800+HP and a LG600 Hewland is $60-80k in NZDollors Thats the budget for the whole car!!! so we will see how this goes???
Cheers Leonmac.
 
It looks that you really know what you are doing, at least you are not afraid of doing it. I admire that "I can do it" attitude. It is actually something that I would like to try out sometime. I could esaily found a Nissan patrol around here, a lot easier and cheaper than finding the "normal" transaxel. I am thinking of building my own chassis, why not a transaxel as well. Keep it up and maybe I'll copy what you are doing.
 
One more example of Kiwi ingenuity. Probably more inventors per capita than anywhere else in the world. What part of NZ ?
 
Does the name Burt Monro enter this conversation? Love the drive and desire. Man after my own heart, keep us informed, heck you may get a few more people who want the parts you are using too, just a thought when you go a casting.
 
Hi those who are interested, My aim is to make the casing semi generic. For example the Diff and pinion shaft could be standard fit and then with a little work there would be no reason you couldn't fit what ever gear stack you like into the case. Obviously there would be some reworking of selector forks and bearing positions but it would not be too hard. Food for thought. Cheers Leonmac.
 

Russ Noble

GT40s Supporter
Lifetime Supporter
Length to the rear of the shift rod in its most rearwards position ie 2nd or 4th engaged is

G50/50 500
G50/52 646

You may need to subtract approx 100 if you want the distance to the rear of the housing

The G50/52 has a large mount cast onto the rear housing. Much of this can be removed and the shift rod shortened

G50/0x should be the same
 
Thanks Russ, just looking at a comparison, I should be about 550 not including the oil pump.

Pablo, I'm in New Plymouth, Its in the Nth Island. All the really clever ones tend to come from the "Mainland" the deep south, My claim is that my family roots are in Southland.

Cheers Leonmac
 
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Keith

Moderator
Thanks Russ, just looking at a comparison, I should be about 550 not including the oil pump.

Pablo, I'm in New Plymouth, Its in the Nth Island. All the really clever ones tend to come from the "Mainland" the deep south, My claim is that my family roots are in Southland.

Cheers Leonmac
A Kiwi friend of mine runs a farm just outside New Plymouth and says it's a real hotspot of bars and clubs with a 24 hour economy, or was he just pulling my leg?

:rolleyes:
 

Russ Noble

GT40s Supporter
Lifetime Supporter
Not just New Plymouth Keith!

The whole country is a cocktail of fast cars, loose women, sex, drugs, and rock and roll. That's why we never get anything done on our cars.....:chug:
 

Keith

Moderator
Not just New Plymouth Keith!

The whole country is a cocktail of fast cars, loose women, sex, drugs, and rock and roll. That's why we never get anything done on our cars.....:chug:
No seriously! That was the info. Of course, there is a story attached to my original statement, but obviously this is the wrong place. Russ, tell me where we can meet so I can explain properly please....

No biggie really.... but I laughed....:drunk:
 
Leon do you have the pics of the original diff and trans as well as the applications they were originally used in? I am currently acquiring the parts for my own transaxle build. Just need to find that toploader that needs a new home. Honestly though this is really nice work that you are doing here. I wont even attempt a casting until I prototype my ideas and run them to death in a heavier car than they would ever be installed in. Besides you can make a lot more torque with a cheap big block for testing these things out.
 
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