Will this WORK???
 

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

Yes, a friend did it in his 40 ford p/u running behind a buick straight 8. 12 forward 8 reverse. Mounts were a nightmare but (joke follows) he could start it put it in gear, go take a shower and have breakfast and not have it leave his really short driveway. Four on the floor AND three on the tree with overdrive knob.

Flywheel for engine, clutch disc of appropriate diameter from trans. pressure plate from engine.

Same process for slush box: flexplate from engine, drill 3 or 4 torque converter holes from tranny TQ. FORDS or CHEVIES are usually the same engine mount pattern across models.

The most important question: is it worth it? The ranger has 10 forward, 2 R, I use 3 mostly.

Well I THINK it will be worth it IF my van gets 20+ MPG On the highway and if my Ford goes from 20MPH to around 30MPG like the Mercury I have before it did.

I really think it will be of more use in the van as a gear spliter, because there are some hills where you cannot pull it up in 4th and third revs the motor too much so you have to slow down for it, splitting third just might work as a good go between gear.

And as my van is a RV and I do not plan on any heavy loads or any towing it should work fine.

Rich

Seems a gear vendors overdrive/under drive is the normal, simple, way people accomplish this. They run $3000 new but there are used ones out there like anything else. My van gets up to 30 mpg highway, why not dump the big van and big car and use a minivan in place of both. Then you also save insurance and liscense fees. It cruises the highway as well as a crown vic with a more comfortable seating position, also has literally a ton of payload with the seats removed, and takes full size 4x8 sheets of plywood.

Well my Crown Vic Coast me $550.00 and a little sweat in repairing a few things. So at this point I am in around $1000.00 in her, AND I nave a 04 Junker for parts.

It is fairly easy to repair and there are tons of them around.

It drives like a sports car and is fast.

My van carries four, has a bed for two, a cargo hold that can hold 6 to 8 apple boxes, and my tools, a tow bar should I have a major brake down, rides fantastic and can clime the mountain going east from Indeo CA to AZ and stay at speed.(65-70 MPH)

Ones like it are now what is being sold for around $10,000.00 and it is all paid for.

SO spending around $400.00 to $1000.00 make complete sense to me.

And I should have a little 2002 Ford Explorer v6 5 speed auto to use a s puddle jumper. Projected cost out of pocket $300.00.


Rich

PS The one thing I cannot do with any of my cars is carry a 4x8 sheet.

Im with you there on the van. My dodge surfer van had the same issues except I ran the bed lengthwise and could haul a 4 x10. Took me many years and bunches of mods to get to 15 mpg. Aero drag was my primary problem. But always had to down shift for hills under 65 mph. 2 kids ended that problem, had to buy the F250 which used to get 25 mpg before they started altering fuel.

Well at least I am at the point you finished at as my Chevy gets 13/14 MPG.

I will be putting a replacement motor with a Tune Port Injection system which is suppose to give 30% more Torque, HP and MPGs so that should give me 4.2 more MPGs getting me to 18 MPG on a good day, and with a special board added to the PCM giving me a lean burn cruse which took 85-90 Camaros from 25MPG to 30/34 MPG I should break though 20MPG and then add in a second OD.....who knows 25MPG???

Rich

https://ecomodder.com/forum/showthre...mpg-33961.html

Read the above

You will have better luck with that approach

One can overdo it with gear meshes (lossy drivetrain) and too high gearing (can't pull it unless going downhill) or maybe can pull it empty but still too low rpms- out of the BSFC sweet spot.

If you slow the engine down too much you fall out of its efficiency range. Even worse yet, combustion and crank shafts harmonics tear up the rod bearings.

Figure out the lowest recommend cruise rpm and gear for that.
Pushing the operating range down to say 1,000 rpm is just going to ruin the engine.

Interesting read. Thanks.

I wish someone would have done a Big Chevy van.

Thanks.

Rich

I have considered this and feel one more OD will not make that happen, but it is a concern.

Rich

I have considered that. My plan are for our highway speeds of 80MPH.

These are both low RPM motors, the Ford 4.6 comes with a factory Ford version of the 85/90 Chevy Tune port injection system with the extra that it has a Sequential injection system which has the better use of fuel and may get great MPG, VS the Chevy batch injection system... On the other hand I can get a special add on board to allow a lean burn cruse customize to its best setting for the Van.

Both motors are low RPM motors, both are unable to run faster than 5500 RPMs and both are past their power peek curve (4500) at those points.

Both have lockup Torque convertors.

Both motors seem to have plenty of torque at around 1000 RPMs with my target range of around 1500 RPMs.

From all I have read and tested I really think this will work.

Thanks for your input.

Rich

Here is some interesting info on the idea of a second OD on OD automatics.

Ford Auxiliary Overdrive unit for Automatic Transmissions | Gear Vendor Overdrive - Drivetrain

The three lesser features to this conversions, First is that Gear Venders is only a 22% overdrive, the Borg Warner is a 72% over drive.

Second it the $3000.00 price.

Third there has been some questions to it durability.

Rich

There are 5 and 6 speed transmissions that have very wide gear spread already. The modified NV4500 I have in my Suburban has the following ratios: 5.61-3.04-1.67-1.00-0.643 which is a 8.72 gear spread.

With 4.10's first is unnecessary for a torque down low engine, so I take off in second. Thus the vehicle could support a much taller rear end ratio and still take off fine in first, to the point that the overdrive ratio could be pushed to the limit of the engine's torque curve versus road load. For example, with 235/85R16 tires and relatively common 3.42 gears I would be turning 1208 rpm at 55 MPH. All with only one transmission and no auxiliary devices. With 3.08 gears this would be 1088 RPM. This is probably beyond the reasonably limit of most engines without drag and weight reduction to reduce the road load.

For 2wd applications there is the Tremec 6060 with 2.97 first and 0.50 overdrive. Less gear spread but more intermediate gears.

So given there are existing single transmissions with such spreads, I don't see the point in using multiple boxes outside of specialized use cases (e.g. rock crawling).

My problem is I am very happy with both the Ford and Chevy power.

The part I am NOT happy with is the gas millage, 23MPG highway for the Ford and 14MPG highway for the Van.

The Ford is all set up and other than a few minor improvements I do not expect to find big MPG improvements in it.

The Chevy needs a better injection system and PCM changes.

Your talking about transmissions I cannot use in either of my cars. If I did they would cost a lot to convert. As much as my idea to convert to the 6 speeds and 8 speed transmissions.

The idea of adding a over drive seems like the lowest cost and biggest change for better MPG.

It stops my search for those rare low ratio rear end gears, same search for those 6/8 speeds transmissions and fittings, and saves the costs of rebuilding the two rear ends, the costs of shifter and computer controls for those new transmissions.

All I need do is mount the B&W over drive to the transmissions, it is cable and electrically controlled, simple to set up and use.

With the van I also think the gear splitting will help find a best fit of power-RPMs-speed in hill climes.

Rich

I was talking specifically about your Chevy van, I don't have much experience with ford engines/transmissions. Both transmissions I mentioned will bolt right up to any engine offered in a 1993 Chevy conversion van. The 1991 K2500 Chevy with 5.7/350 TBI I converted from a 4l60 to a NV4500 cost me about $1000 total to convert, used transmission new clutch/flywheel.

It would be drastically less work to put in a period appropriate transmission into that van (like a NV4500) than to try to bolt two transmission together or to hook up an auxiliary overdrive unit. It would be way easier than some new exotic 6 or 8 speed auto. I have converted two 90s model Chevy's from auto to stick, a pickup and a Suburban with a 4l60 and 4l80e respectively. I am sure your Chevy van has one of those transmissions. The correct sensors just bolt right up, everything works fine.

If you want a more complicated project a Tremec 6060 should bolt up to the engine but may require some other custom work to fit.

The THING is I do not want a stick shift. I much perfir automatics.

On a long trip coming into a city and having to drive, look for directions, find the hotel is all I want to handle, having to work a clutch and shift is too much.

As a teenager I switched a 56 Studebaker Golden Hawk from an auto to a 3 speed with overdrive. My next car was a 68 Mercury Cougar XR7 with a 4 speed. My Ecnoline Van had a 3 on the Tree.

We have VW Bug with its 4 speed and we had a 86 626 with a 5 speed.

I have driven enough Sticks to know them and myself well.

For fun give me a stick.

For work car or truck (van) give me a auto.

Rich

The slowest I have seen a tall geared V8 chug along is 70mph at just shy of 1,600rpm.
Just make sure what speed you run at makes good oil pressure.

Your preference will cost $$$

IF the bottom line was just money, then I would scrap the big gas gussying van and get a tiny smart car, or a all electric car.

But I am trying to lower the pain and guilt of driving this BIG great riding van which can also serve as a camper and carry cargo for a business trip.

SO I am trying to get the maximum MPG with in these out lines.

Big customized van, big 350 or 383 Chevy (Because I learned by doing a smaller 305 motor is crap, no power and worst MPG) motor running low RPM cam and TPI injection, big fat 18 inch wheels and tires but sized so tires are stock height, ( These because they are the safest tires I have ever ran, one tire failed at 80 MPH and there was NO control problem and on dry roads give great traction) custom tuned PCM running Lean Burn Cruse tuned to Vans needs, and special transmission, a stock 4 speed with a added Borg Warner Over Drive OR a newer 8 spreed auto with a very low rear end gears.

Even with all that I am working on getting a 2002 Ford SUV Explorer with a V6 and 5 speed which will serve us as a smaller more reasonable run about that is in-between the Crown Vic and the Big Van.

I believe I will have the best good MPG running cars to fit my everyday needs.

Rich

Before my 1989 Diesel suburban 5mt rusted out I was getting around 30mpg highway 2.8 rear end and nv3500
That body isn’t much different than your van

That was not at 80mph and my guess is your not going to get much improvement at that speed

You maybe right, but I got to try...by the way that 14MPG seems to be at nearly any speed above 55 MPH....up to 80/85 MPH...and yes I felt something was wrong, my best guess is it cannot meter fuel at all.

Saw such "performance" on a day trip up I17 to Sedona AZ. and back...odd as a good part of that run was up hill.

Rich

If fuel economy never seems to change you are likely overgeared

A higher rear end ratio in that case should improve fuel economy

That AND/OR poorly regulated fuel supplied by the crappy TBI system, better over fed than dead I think they thought.

But trucks and Vans have always gotten worst MPG that the seemly same motors, fuel systems, transmissions, and rear end gears that came in cars.


Rich

Only word here Aerodynamics. Or as Irv Culver used to say:"drag sucks"

I am well aware, and it may very well be a problem, at this point I have found very little change in the vans MPG from 65 MPH to 85 MPH.

Also this van seems very well Aerodynamic: I found IT was the first Van NOT pushed around by the bow wake of air by the BIG RIGS when either passing them or they passing me, and after 20 years of driving normal vans THAT was a BIG surprise.

Check it out here if interested:

https://www.facebook.com/richardacoy...0269632&type=3

Rich

Afaik drag has to go up with speed. So obviously something is odd here which could make huge mileage gains if altered.
Any instrumentation planned?

Like freebeard, I dont do Facebook, so the reference was non operational.