[Jetmugg]

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.

 

[valiant67]

Try this ink - best info I have ever found on the FWD transaxles.
http://www.thedodgegarage.com/trans_guide.html#460

My bet is the only way to know the difference is from the tag on the transmission.

 

[Jetmugg]

Try this ink - best info I have ever found on the FWD transaxles.
http://www.thedodgegarage.com/trans_guide.html#460

My bet is the only way to know the difference is from the tag on the transmission.

That's good info, but unfortunately doesn't cover the A412, which is the transmission I'm looking at. Thanks for the link.

Steve.

 

[ImperialCrown]

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').

 

[Jetmugg]

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.

 

[Jetmugg]

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.

 

[ImperialCrown]

There seems to be one too many numbers in the VIN sequence line. There should be 6 numbers to end the VIN. If it was a '79 Plymouth TC3, the VIN would start as: ML24A9D, then the last 6 digits.
A 1979 Mopar Passenger Car Parts manual could possibly break down the VW transaxle ID #. The parts catalog has a publication # of 81-690-1403.

http://www.ebay.com/itm/MOPAR-PARTS-CATOLOGUE-1979-PASSENGER-CARS-/130839111367?pt=Motors_Manuals_Literature&hash=item1e769e66c7&vxp=mtr

 

[Jetmugg]

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....

 

[ImperialCrown]

Yes, 5240048 would be the transaxle part #. It is referred to on this page:

http://autopartmaster.com/en/?action=catalog_show&cat=chrysler&t_id=3759&id_pic=36328