1500 swing axle box mods

[GARRICK.CLARK]

Hi Pablo.
I can do 70, but the revs are a little high . Fast street driving I think the ratios are fine . But any long distance motorway driving its a bit thrashy.
I have a 356 top pulley fitted. This works good.
I do some times do a bit of traffic light drags. So I pre load the box with the hand brake on. NO clutch side steps tho.

[gkeeton]

You're just going to have to get the trans apart, and count the teeth to determine if you have a 3.78. Another thing to consider would be that the splined mainshafts use a different bearing in the gear carrier than the keyed shafts. To put a splined shaft in a your current Type 1 box, you would either need to have the mainshaft turned down in diameter, or obtain a later gear carrier with the correct bearing. A 3.78 is an upgrade to a 3.80, but they cannot be simply interchanged with each other. If you are taking your components to a transaxle shop, they should be able to give you an idea of what else you may need. And yes, I'm a proponent of installing a super diff, but Pablo is a fan of double snap ringing a stock diff, and using the 15 tooth side gears with two 10 tooth spiders. The 15/10 combo may be your least expensive option.

[petew]

Hi Garrick, as I suggested on the Cal Look forums, there is a better base transmission to start with. This is the late 1300 swing trans that starts with an AB code. You should be able to find plenty of them in the UK. I know you guys got lots of 1300s in the 70s. A good core only cost me $250 (pittance). My trans builder told me with only a few mods it was good for over 150hp behind my turbo engine, as long as I didn't do burnouts or sidestep the clutch. Here are the mods it got...

Billet side covers
Decent superdiff
Steel shim plate between the front housing and nose cose

I had it built with the stock 4:12 for short course club racing, but if I had my time again I'd have gone a 3:88 for the freeway. Although, freeway driving is not terrible. The motor comfortably does 3400rpm at 70mph and 3200rpm at 60mph. Yes it's noisy but even if you dropped it down under 3000rpm, I still think you'll want earplugs if the trans is strapped down in any proper way.

This trans cost $AU2500 to have built. Should be slightly cheaper for you.

On the subject of LSDs. I dearly wanted a quaife. Oh man. I still want one, but it's fine with the superdiff for 99% of driving and about 80% of khanas I do with my car club.

[GARRICK.CLARK]

So with an AB box I could swap the 4.37 ring and pinion for my 4.12 ring and pinion . Fit a Super Diff. Get a Side Cover, Steel plate, hardened keys, weld the 3rd and 4th hubs if the AB gears aren't already. Maybe use the 3 and 4th from my type 2 box If they fit.
Its more complicated than engine building. Respect.

[petew]

This is the specific info David Butler gave me re the AB box...

At a suggestion, the 1300 twin port gearbox is about twice as strong as the 1500, and just a nose cone change with steel thrust plate will do you a long time. It comes with stronger diff internals, steel forks and does not need welded gears or hard keys since it has splines and furnace brazed 3rd and 4th gears.

Specifically you want an AB box with it's numbers finishing in 3 or 4 (1973-74). I'm fairly sure it's a 4:12 from the factory.

[GARRICK.CLARK]

O Yes. Sounds good this Pete. I'll definitely be on the look out for one. Should be loads of those over here.
Are the steel thrust plates easy to come by. Who sells them.
Thanks

[petew]

http://www2.cip1.com/ProductDetails.asp ... D5058%2D10

I'm sure others will have it too. Any decent gearbox builder should stock them.

[dangerous]

AB trans has a 4.373 diff ratio standard.

[GARRICK.CLARK]

Yes , I might have to change it

[petew]

AB trans has a 4.373 diff ratio standard.

Thanks for chiming in mate. Love your work.

[GARRICK.CLARK]

Hi Guys.
I have acquired a KCR swing axle box, It says KCR 94 on the bell housing.
I'm just wondering what KCR did to these boxes way back in the day. Its an AH box so guessing its got a 4.125 in it. There is an ally side plate on it too , that's all I no, I have contacted them but had no reply.

[woodsbuggy1]

I highly recommend the Weddle torsional input shaft, we started using them several years ago in our off road buggies and they have made a big difference in transaxle life.
Kenric

[GARRICK.CLARK]

Torsional input shaft.
Can you explain why its a good thing to have, I'm guessing its made to twist slightly.

[Pablo2]

VW's engineers were heads above Porsche's when they applied the 2-piece "quill-shaft" design to the Bug transaxle. This design itself adds approximately 30% strength to the mainshaft.

The secondary beauty of the design is that it allows the gear portion to be made from premium gear material, while allowing the input (quill) portion to be made from something like 300M, as would be used in high grade axles or torsion bars. So, both features working together allow the relatively puny VW gears to last a surprisingly long life when subjected to abnormal shock-loading.

When we finally adapted the 2-piece design to Porsche racing transaxles, we used a 300M type material for the quill shaft, and Weissach never looked back. I'd recommend using one for any type of racing application.
https://www.thesamba.com/vw/gallery/pix/1567185.jpg