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Discussion Starter #1
I have seen some anecdotal evidence of 2 different R&P ratios in the early Omnirizon 4 speed transmissions, which are a variant of the VW 020 transmissions. These would have been fitted to the 1.7L VW-based gasoline engine.

The ones that I have read about are a 3.48 ratio, and a 3.70 ratio.

Can anyone verify these numbers, as well as any codes which might reveal which transmission might have which ration in the R&P?

Thanks,

Steve M.
 

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The 1978 service manual states the the overall top gear ratios (OTGR is determined by multiplying the ring & pinion ratio by the 0.97:1, 4th gear ratio) is 3.38 for the Federal/Canadian transaxle and 3.59 for California/High Altitude vehicles.
Multiplied by 1.03 for your ratios checks out correctly, 3.48 and 3.70.
A machined pad is provided at the top of the clutch housing for stamping the transaxle # and VIN.
The emissions sales codes determine which vehicle would be equipped with which transaxle (usually 3 characters beginning with the letter 'E').
 

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Discussion Starter #5
That is excellent information. Before I saw this post, I checked the pad on the bottom of the clutch housing, which starts with code GM. I found on another site that the GM code should indicate a 3.48 ratio, but it's not a slam dunk yet.

I'll check the pad at the top of the bellhousing for the transaxle and VIN#.

I'm hoping that I have the 3.48 ratio.

Steve.


I suspect it will be the 3.48, based on the fact that the vast majority of vehicles would have been equipped with the Federal/Canadian setup. This one was found in Missouri.

Steve.
 

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Discussion Starter #6
I just checked the numbers stamped into the bellhousing.

The top line is GM08039
The 2nd line is 5240048

If my memory is correct, this trans was pulled from a '79 Plymouth TC3.

Steve.
 

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Yesterday, I managed to get in touch with a guy who uses these Omnirizon 4-speeds in a racing application. He seems to know quite a bit about these 4-speeds. I'm trying to learn as much as possible, as quickly as possible. The top line seems to break down like this:

GM = 2 letter code for this VW 020 transaxle.
08039 = March 8th, 1979

The lower line of digits being 5240048 does not seem to be tied to the VIN. It looks like this is simply a transaxle part#. He tells me that the last 2 digits being 48 indicate that it has the 3.48 ring and pinion. Here's a pic of the stampings on the machined pad of the bellhousing....

 
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