[racprops]

In another thread I asked why this will not work??

The question of this hour is:

Can you run a add on second overdrive behind a transmission with its own OD gear and run in both ODs at the same time.

The other thread was about:

I was asking about running a 6 and 8 speed transmissions in a 2003 Ford Crown Vic and a 1993 Chevy Van using VERY low gears like 2:26s.

This was a very helpful thread and ran 5 pages and ended with the question: "Did I know about the old Borg Warner 3 speed with OD?"

It was suggested you could mount the Over Drive, a transmission in its own right mounted on the back of a 3 speed stick shift transmission allowing it to be engaged in any of the 3 gears of the front transmission.


It was suggester that the OD unit by its self once removed from the 3 speed could be mounted in back of many automatics used in 4 wheeler cars/trucks using the adaptor for the 4 wheeler take off transmission.

This took me back to in the 90s where I WAS planing on adding a 3 speed with OD behind my then TH400 with a Switch Pitch convertor.

This would have served as a high and low range by using third as high with my low gear rear end (same plan on using a very low gearing) and second as low range.

I would then have 3 auto gears plus the OD making 4 gears in low and 4 gears in high range.

Seemed like a good idea, at that time.

It was very complex set up needing second stick shifter and controls for the over Drive.

Now I felt using a modern 6 and 8 speed again with a very low rear end gears would be the better answer.

But there are a number of problems. With the Ford 6 speed finding a flywheel is impossible. And finding any lower gears than a 2:75 is also very hard. Then rebuilding the rear end is costly unless I do it my self. So the special rear end could cost from $500.00 to $1000.00 for both the Ford and the Van.

Then there is the cost of a good used 6/8 speed autos, installing them: mounts, shifter controls, shorten drive shaft, VSS senders and a electronic controller to replace the missing PCM computer. Est. $2000.00 PLUS.

It still seemed worth it. How?? Because I plan on driving these two cars until either I or they drop dead. And as I can repair them it will most likely have to be me.

But this new old idea make a LOT of sense.

I have two 3 speeds with the heavy duty ODs behind them.

So all I need do is figure out how to mate them behind my two stock transmissions using one of those 4 wheel adapters, move the transmission mount to the mount on the OD's tail, and get a special shorten drive shaft with its own slip joint, hook up the controls for a OD, (a cable an some minor electric controls) and add a VSS sensor to the tail of the old OD.

And I now have 8 gears (by splitting the for suto's 4) and a super low final drive without having to find gears and rebuilding my rear end, or installing whole different transmission.

I also drop a lot of costs this way.

Stock PCMs, Stock transmissions.

And one extra, the OD's free wheeling so I can even hyper mile.

Seems I have come full circle.

Rich