SSC internals

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jamesbissland
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SSC internals

Post by jamesbissland » Sun Feb 21, 2021 12:18 am

Hi all,

I am getting a swing axle trans (trans code AC / 4.125) rebuilt for my bug.

I have a 73 SSC IRS trans (code AT / 3.88) in the shed that was put away for a rainy day.

At the same time Im get a fuel injected 2276cc engine with Web 86B built.


Question for the gear box wizards.. can any of the components out the SSC fit in the swing axle trans?

Ive head the SSC have stronger gears etc..

Looking forward to all your comments

Cheers :)

Bruce2
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Re: SSC internals

Post by Bruce2 » Sun Feb 21, 2021 6:19 am

Lots of parts can be switched around, but you have to know what you're doing. What interchanges depends on when your AC trans was built.
What is its trans code?

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jamesbissland
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Re: SSC internals

Post by jamesbissland » Sun Feb 21, 2021 11:45 pm

Thanks Bruce

It’s really hard to make out the number, but it looks like
AC09941
It has twin drain plugs but no sleeve on the input shaft

Came from a NZ new 69 1500

Cheers

Bruce2
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Re: SSC internals

Post by Bruce2 » Mon Feb 22, 2021 6:55 am

The last year for twin drains is 69. 69 is also the first year for the two letter trans code, so you have a 69 trans.
Do you want the 3.88 R&P, or do you want to stay with the 4.12? What are you going to use the car for? Long trips on the freeway? In town only, with only short trips on the freeway?

Likely you will want the stronger 1st gear. The problem you will find is that the stronger 9 tooth first gear's shaft has a splined connection to the 3-4 clutch gear. This means you need to use 002 type gears. You can convert the 113 type gears from your AC trans, but there's welding and lathe work involved. Can you handle that?

You might be thinking about using the gears that came on the stronger shaft. Sadly, they aren't the strongest. They are fine tooth gears, and are known for failing when a trans is shifted hard. The hard shifting causes small chunks of steel to break off. These small chunks then go floating around in the oil. When they find themselves between the gear teeth, the fine teeth chip off. I've seen some gears that were working just fine but had 5-6 chipped teeth spread all around the gear. As you chip off more teeth, more bits of steel are floating around, causing more teeth to chip off.

If you want stock gears, there is a stock solution. Get the 3rd and 4th gear sets from a 1975 Bus trans. Then they assemble onto the stronger main shaft with no modifications.

When the trans is built, both gearboxes will be apart to donate parts. Using the 9 tooth main shaft means you'll be using the gear carrier casting from the SSC trans. And the main shaft bearing that goes with it.
The 1-2 slider in your AC must be used. It will be a 2 line slider. The reason you have to use that is because of the reverse idler gear. The one in the SSC will NOT work in your AC case, so you must use your original reverse idler. It then requires the 2 line 1-2 slider.

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jamesbissland
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Re: SSC internals

Post by jamesbissland » Mon Feb 22, 2021 7:00 pm

Thanks so much for your time writing that up Bruce.. very valuable information!

You mention about freeway vs driving around town..

Most of my driving will be around town, with the odd couple hundred mile trip on the open road. We don’t really have freeways down here in New Zealand. If you exceed 60mph on roads down here you get hit with the book of the law

Would that change your decision regarding boxes?

I asked about the SSC as I had heard (as you have confirmed) they use some of the Kombi gear sets, which I had assumed would be stronger..

I guess at the end of the day I am after something I can drive around town with the odd long trip, which will be reliable, yet not poop the bed if I put my foot down with a 2276

Thanks so much again!
James

Bruce2
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Re: SSC internals

Post by Bruce2 » Tue Feb 23, 2021 5:01 am

jamesbissland wrote:
Mon Feb 22, 2021 7:00 pm
If you exceed 60mph on roads down here you get hit with the book of the law

Would that change your decision regarding boxes?
Definitely use the 4.12 R&P from your AC gearbox. If they don't allow speed, make up for it with acceleration!

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Clatter
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Re: SSC internals

Post by Clatter » Thu Mar 11, 2021 11:29 pm

FWIW, I always liked the 3.88/3.78 1st combo better for around-town driving with a light beetle and big motor.
So much nicer to drive in the crawling tourist/small-town low-speed driving we do here..
With a 4,12/3.80 1st, you're shifting to 3rd before you're even through an intersection.
This being a big motor and a light beetle with maybe a bit shorter tires, mind you.
Still.. Makes it a lot easier when 1st is usable for more than just a nudge to get moving, and 2nd provides a bit of driving,
Unlike the earlier trans that is a shift up through to 3rd every time..

FWIW, JMHO.
Speedier than a Fasting Bullet!

Beginners' how-to Type 4 build thread ---> http://shoptalkforums.com/viewtopic.php?f=1&t=145853

Bruce2
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Re: SSC internals

Post by Bruce2 » Sun Mar 14, 2021 3:07 pm

Where I live, the urban speed limits are 30mph. With a 3.88 R&P, that's just a bit too slow for cruising in 3rd gear, especially if the guy in front of you slows to 25mph. With a 4.12 R&P, 25-30mph works fine in 3rd gear. In the parts of the USA I visit, urban speed limits are commonly 35mph. At that speed, 3rd gear in a 3.88 trans works just fine.

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