Rear End question about gears and overdrive.

Hi everyone.

I was just about to pull the trigger on a rear end swap on my 1973 Plymouth Satellite. I have a mild 360 in it right now (318 stock), but I'm planning to either do a 408 stroker kit in it or drop in a 440. I already swapped out the 904 transmission to a 727 with a shift kit. I believe the stock rear end is a 8 1/4. I was going to swap to a 8 3/4 or a Dana 60 but from what I am seeing online, the 8 1/4 can handle up to 500 hp? I need to install a Suregrip either way. For gears I was thinking about 3.23 for the highway, but I just found out about transmission over drive kits. I am thinking a 3.55 rear end with a Gear Vendors might be beautiful. Do any of you have this set up, what are your thoughts? I would like to keep a nice top speed and get out the door fast. Do I really need a rear end swap or should I build the 8 1/4?

In part, it depends on what you will do with the car and tires you run. With common street tires the 8 1/4 will take a lot. With sticky tires or slicks and hard launches the torque in 1'st gear can do it in pretty fast. Axle torque and traction are the limiting factors more than HP. The 8.75 is a bit stronger but would get marginal with a 408 or especially 440 and sticky tires. The D60 would be pretty much bullet proof.

3.23 is a nice all around gear... OK for the highway and decent acceleration. Maybe keep the 8.25" and see how it goes. OD is really nice if you are spending time on the highway. Including with 3.23's. If you want to drag race probably need something like 4.10's for best results.

I agree with most of what ahy says. The only exception that I would take is that he feels that an 8 3/4 would be "marginal" with a 408. I run a 489 8 3/4 in my Cuda. 3,500lbs, 500" stroker, 4000 stall, 3.91s, and drag radials. The car will pull low 1.5s 60 foot. I get years out of my gears before they get noisy.

A 60 is pretty much bullet-proof, but an 8 3/4 would be cheaper, easier to set up, easier to find, lighter and eat a few less ponies while lasting a very long time. And is much easier to change gears in should you want to try a different ratio.

Also, if I am not mistaken, I believe that many Dakotas came with an 8 1/4 with 3.55s and a Sure-Grip. And the junk yards (pick-a-parts) have a lot of them now. $50 will buy the gears and carrier at most places if you pull them your self.

Good luck with what ever you decide.

I don't agree that the 8 3/4 would be marginal, especially with an auto.

HOWEVER, if you are going to buy a new rear anyway, why not just spend the extra and put the D60 in, then no matter what you may eventually do, the rear is done. In the long run it may very well be cheaper.

It is unfortunate you already spent money on that 727. An early 90's 518 transmission out of a dodge rwd truck/van would be the ticket for you. It's basically a 727 with a .70 overdrive gear. It will bolt straight up to a small block (perfect for that 408 stroker idea of yours) or mate to a big block with an adapter. The 518 could be made to fit under your car with a minimum of fabrication(shorter driveshaft, custom transmission mount, possibly some crossmember modification. Also the 518 has a superior overdrive gear to the .80 on the gear vendors. With the 518, you could do 4.10 rear gears and on the highway it would drive like a 727 with a 2.87 rear gear.

Either way, I would get your transmission choices nailed down, and worry about the rear end later.

I'm not a small block guy,...but Man does that package sure sound sweet! I give it a

No biggy,...but wouldn't the 8.75 be a 4.11 though?

The 4.11 ratio was never offered in a Mopar, the 4.10 was. I know, it is only a small difference but we strive for accuracy here, right?

I "sit" corrected.

Wish I would have know about that option back then. But I am happy with the 727. I think the Gear Vendors is .78, but yeah, it only makes a 4.10 drive like a 3.20

However, it looks like 518 is only one extra shift in the 3rd gear high range. Gear Vendors provides 1st over, 2nd over, and 3rd over. The drop down to 2nd over is supposed to be amazing for highway passing power, and the launch mode for 1st sounds like it adds launch speed without needing to jump up to 4.10 gears.

I have the gear vendors unit with 3.55 gears. It works great but you may have to messaage your tranny tunnel plus make sure your pinion angle is right. May have to shim your rear axle for the correct angle.

That being said. I don't see how you will be able to use the unit as a six speed. It has a slight delay when it shifts. How do you expect to shift back down exactly when you shift up to 2nd gear. I just use it as an overdrive and I will use it to split 2 and 3 gear when racing.

You won't use the 1st over, 2nd over. Go read reviews from actual owners, 90% of them say it's useless for anything but a highway OD, with gear splitting too insignificant to produce an ET gain at the track. IMO selling your 727 and doing a 518 would be more cost effective and more useful than the GV. If I was in your shoes I would definitely still consider it.

Also FWIW, I almost never need to downshift to pass with my 1.8L stick shift daily driver. I would have to question the driver if passing downshifts are something you need to worry about with a 400+ cube engine.

Great info here, I love my 518, makes the car so much more enjoyable to drive.

http://www.cuda-challenger.com/cc/index.php?topic=84774.0

According to their website, overdrive in 1st is auto when you engage it:

"Another great feature of the GEAR VENDORS is that you will have a full 6 forward ratios when you switch to manual on the dashswitch. Pull into low, then hit our button (on the shifter or the floor), a red light appears indicating our Auto-Launch circuit - as you are accelerating through 1st gear the overdrive will automatically shift to 1st-over. This is directly related to the rear end ratio in the car - so that a 4.56 rear car shifts earlier than a 3.55 etc. If you have a 3.25 or 3.55 rear this brings a whole new level of performance and has a whole bunch more torque multiplication than you have ever felt in your car before. With a 3.55 rear for example the torque multiplication in 1st-over is more than 4.56 diff car would have in 2nd - awesome performance gains. After you have revved up in 1st-over then shift to 2nd and turn us off. Then rev back up and hit the button for 2nd-over for the same benefit (that 3.55 example now get a 4.01 gear)."

I like to keep a balanced view of products I'm researching, could you link me to some discussions? I keep finding positive reviews.

You would need bionic body parts to be able to quickly shift into and out of the GV OD if you expect to improve your times over a standard automatic. The gear splitting feature is a BS marketing gimmick that really only applies to limited rpm mills used for towing and such.
I'd say higher than 90% simply consider the add-on as a 4th gear, not the 1, 1 over, etc.

I'm too lazy to do a search for you, but there's been plenty of discussion about it on this website coming from actual GV owners. Overdrives are great, makes these old cars way more driveable. I wouldn't put too much faith in the gear splitting marketing goodness. Some food for thought, a 408 or 440 has a very broad torque curve. A 2.45 first gear x .8 = 1.96. Second gear is 1.45, close enough that a good aftermarket torque converter should hide most of that difference. A 1.45 second gear x .8 = 1.16. Third is 1.00.

I grew up driving a 2-ton grain truck. When you are hauling 30,000 lb of truck and wheat with a 304 cubic inch engine, split shifting with the two-speed rear end helped to get up to speed faster. You have many seconds between each shift, like 8 or so at full throttle.

The GearVendors overdrive IS the Laycock deNormanville overdrive that was used in British sports cars in the '50s and was used behind Volvo four speeds in the '70s, when they didn't want to have to buy a 5-speed. At the time, even with a 2-liter four cylinder pulling the 245 wagon, no one ever tried to do any split shifting. This is the same as what happened in the States in the '50s with the Borg-Warner overdrive found behind many 3-speed manuals. The shift pattern was 1,2,3,OD. For the Volvo it was 1,2,3,4,OD.

It takes about a second to shift into Overdrive and I think you have to get off the gas a little. On a 0-60 run in 6 seconds, where is the time to shift the overdrive box?

I think the GearVendors people would tell you they aren't advertising that at all. They are advertising the extra ratios that allow one to tailor the gear ratio to conditions. For example, going over a 10,000ft mountain pass in a pickup with a typical granny 4-speed can mean you spend several miles in 1.7:1 ratio Third because it won't pull Fourth at that attitude. So there you are with the engine singing along for mile after mile. Yet every time you stick it into Fourth the truck slows down to a crawl. It'd be nice to have a gear in between. That's what the GearVendors can do. Shift down into Third and regain your speed, then shift into OD. Third OD has an overall ratio of 1.36 which the engine can pull. Everything is so much more relaxed.

That's the other advantage of the OD besides flatland cruising.

Knowing the origins of the GearVendors OD it is amazing to me that they have increased its torque capacity by something like a factor of three.

BTW, the internal workings of the GV look very similar to innards of a TorqueFlite, a planetary gear system with a multidisc clutch. The pressure for the clutch is provided by a pump in the casing. Hint: If the pump inlet gets clogged the OD won't work, but you still will have direct drive.

R.

My Dart has a stockish 318 with A518 behind it and 3.55 gears in the rearaxle.
With a more torqy-er engine I think I would like to use 3.23 gears.

The A518 adds more driveline drag then a A500 transmission which is based off a 904 (which also have a better first gear gearing).

Okay I think I understand now. The Auto launch works well for 11 second or slower cars. In a 3 speed automatic you would engage the overdrive BEFORE you start driving while the column shift is in first. As you take off the electronics automatically shift into 1st over and then you manually shift into 2nd and hit the button again. I see where there would be no time if your car is 10 seconds or faster. I saw one conversation mention that Gear Vendors makes a AutoShift Sequencer to add on to the overdrive if your car is 10 seconds or faster, but I'm not worried about that. At this time I don't plan on building my car into a 6 or 8 second car and like you guys stated, the main thing I'm after is highway cruising rpm with 3.55 gears. That 518 swap DaytonaTurbo recommends is sounding more interesting. Thanks for all your input so far

This is the point where we end the gear splitting discussion. It's not needed in a torquey engine with a broad rpm range.


The only thing I'd like to add to the 518 swap is there are many pros mentioned. I've done it and liked it, from a 904 to a 518 to a 5 speed manual.
The only cons against it is, it's not an efficient transmission. Without taking over the thread with my data I'll condense it. With my 904, excellent mileage but poor acceleration due to tall 1st and tall rear ratio. 518 was quicker due to steeper rear but the mileage was still poor, I blame the lack of efficiency, the only advantage was high cruising speed and low rpm due to tall overdrive. Finally the 5 spd gained me 3 mph in the 1/4 and 3 mpg while speeding.

Just want to add, if you go 518 you need a steep rear gear. The 1st gear is tall and so is the o.d.

(It takes about a second to shift into Overdrive and I think you have to get off the gas a little. On a 0-60 run in 6 seconds, where is the time to shift the overdrive box?)

Wrong! I have a GV behind a 511 stroker. The shift to OD is instant and you do not need to get off the gas a little, keep it to the floor.

(BTW, the internal workings of the GV look very similar to innards of a TorqueFlite, a planetary gear system with a multidisc clutch. The pressure for the clutch is provided by a pump in the casing.)

Yes it is a planetary gear. The clutch isn't multi-disc, it's a cone clutch. Correct the GV has its own internal pump and sump. It's a single piston pump, about 3/8 di.a.

I'm not trying to be a smart a$$, but have you ever driven a car or truck with a GV installed? Have you ever actually opened one up and looked inside?

As far as the split shift goes it's not practical. Since I have a manual reverse valve body I drive mine like a four speed. 1, 2, 3, OD. If I'm getting on it hard, it's 1, 2, OD, 3. I disabled the GV auto feature and manually select OD. The only draw back to disabling the GV auto feature is you have to remember to deselect OD every time you stop.

"This is the point where we end the gear splitting discussion. It's not needed in a torquey engine with a broad rpm range."

Wow... Pretty arrogant to pop into a thread and try to steer it the way that you want.

My week long experience with a Gear Vendors on a 727 with a stockish 440 was that it was not enough overdrive to warrant the expense and the gear splitting was slower than leaving it alone and shifting it into the overdrive in 3rd.

'Refreshing' to see this mentioned. Most peeps usually 'talk it away' by just saying they're happy with it after having spent about $3k?

Interesting..

My 67 Coronet has 294 gears in it ( automatic) as I like to drive it places.. They are getting boring though...

My research shows a 355 geared car with the GV unit would have an OD comparable to 274 final gears???

Seems pretty perfect to me??? What am I missing??

My 69 Bee 3.55 gear + GV = 2500rpm @ 80mph. My engine is happy, I'm happy. Was it worth $2600? Yep every penny!

New development to my project:

As rear ends go, I have had a few recommendations to NOT do a Dana 60 due to the additional weight. Some guys that race Mopars at the track are actually recommending that I go with a Ford 9 inch. Have many of you heard of this swap? What are your thoughts? I'm making the final choice in a day or two.

Car Craft did a test, used the Dana 60, the 9" and the 12 bolt.

http://www.hotrod.com/how-to/transmission-drivetrain/ccrp-0806-chevy-chevelle-rear-axle-swap/

Some facts for you rather than anecdotal bench racers opinions.

Sheesh . . . if you are thinking Ford 9 inch, then why not go with Mopar 8.75 ??? There were many made for your car . . . just an FYI . . . as was mentioned before, depends what you want to do with your car. I have a 74 Duster360, original 360, 727 auto. It had original 8.25 rear end with 2.94 gears, thought I would like more, so got 3.55 sure grip installed. However, I like driving long distances . . . so these really didn't seem like what I wanted . . . before going to Carlisle, PA show in 1999 I swapped out complete rear for another 8.25 with 2.45:1 gears ! Much happier !!! The 360 still cranks over the right tire (yes one legger) no problem, travelling down the road at 75mph, engine ticking over at 2600rpm, and mileage around 22/23 mpg all day long ! . . . Just my two cents worth . . . build the car YOU want ! . . .

Cheers

Mark

That is a lot less weight difference than I thought it would be.

Wonder if disc brakes would drop the weight more.

Late to the party, looks like a lot of info to pour through in this thread.... but just want to offer that the mere thought of putting any money into an 8-1/4" is silly. And no, it won't stand up to ANY sort of real torque. Whatever website you saw that said it would stand up to 500 hp.... Don't go there anymore.

What rear gear were you running and what tire height?
I'm at 2650 RPM's at 60 MPH on the highway in my Duster with 3.55's and a 27" tire, I know darn well an overdrive button would make me much happier at around 2100 RPM's.

Probably because the 9" is about 10 times stronger. There are alot of fast cars with 8.75 rearends but alot of them break too.

Not stock they aren't.

This is a good point. A 9" is a good rear end, but mostly because the aftermarket has offered them a lot of support. In stock form, they are a far cry from a Dana60, which can handle just about anything in bone stock form.

I was just reading this for fun and have no overdrive info to add but I feel I need to plead with you to NOT put a Ford 9" in your Mopar! You have an 8-3/4, 9-1/4, and Dana 60 to choose from so there is no reason in the world to put another brand of rear end under your car. Please don't be that guy!!!

I also have a 67 Coronet with 3.55 gears and a gear vendors unit. I have three cars with gear vendors units and I very happy with them. Found all three on craigslist and bought for less than half of new price.

Also have to add what others have said. I use it as an overdrive only because of the slight delay.

Stay calm everyone, I'm pretty sure I'll be doing the Dana 60

Hey rapom, when you picked up the gear vendors used did you have to change anything on them? They seem to be tuned for gear ratio and tire size.

Any over drive trans will produce about the same effect as the Gear Venders unit at a much lower price. The only advantage the GV unit has is it can handle more power. The 727 version of the Mopar overdrive automatic can be as stout as your current 727 or most of the Mopar OD 4, 5 or 6 speeds will work at probably 1/2 the cost of the GV unit, even after converting them to fit your big block.

My 93 Dakota 4x4 pickup has a Magnum V6, 500 auto od, 3:55 8 1/4 rear and 235-75-15 tires. It will roll down the road with the od off (switch on the dash) at about 2600 at 60 mph. Turn the od on, and the rpm drops to about 2100, and when the converter locks up, the rpm drops to about 1800 at 60 mph. The V 6 doesn't have enough balls to pull a long hill at a steady 60 (it does better at 70) without unlocking the lockup converter, and if its a really long hill, it might drop out of od. Out of od, I can gain speed going up nearly any hill. A V8 would probably pull the hills without issues. On the highway, my 4x4 Dakota gets around 20 mpg at 70 mph. Gene

The only thing that needs to be changed is the speedometer gear. The manual has a chart that matches the speedometer gear with the gear ratio and tire diameter. The gear Vendors unit uses turbo 400 speedometer gears which are readily available on ebay.

The 9" is a great option for many of us, I had one in my 9 second DartSport. They are durable, have a drain plug in the bottom, a removable center section carrier, and a much wider variety of gear ratios, especially for highway type gears.
I also had a Dana in my '69 Dart and I liked the 9" alot better.

I love my Mopars and Mopar engines but I could care less where the tranny or rearend came from. A turbo400 and a 9" is a perfect combo.

What was so much better about the 9" over the D60?

Here are a list of things that I know make the 9" better.

Lighter weight

More gear options. I don't believe you can go under a 3.55 with a Dana 60

Able to lower your car easier because 9" pinion is lower on the pumpkin than a dana 60.

easier to set up ring and pinion on a 9"

Possiblily cheaper to set up.

Larger pinion shaft diameter.


Dana 60 pluses are
More efficient transfer of power due to placement of pinion gear to ring gear. Not sure of the HP loss but there is a bit with a 9"

Looks cooler to me at least.

Looks more factory on a Mopar.

You missed one of the biggies, easy swap of center section between rounds and races.

I have a Dana with 4:30s and a GV. The GV is life altering. I've been very happy with mine. They do add some extra weight to the car though if you care about that sort of thing. The GV is bullet proof. I'm throwing decent HP at it and it's holding up fine. I've raced with it and driven on long cruises with zero problems.

I mentioned my favorite reasons in the paragraph you quoted ^^^

First of all, the 9" is NOT lighter. In order to gain equal strength, the 9" and D60 are equal in weight.

There are options all the way down to 3.08 gears for the D60. If you need taller than 3.08 gears you need an over drive, because you have compromised low (1st) gear.

I have no idea why you think ride height is compromised by pinion height.

It takes me the same time to set up a D60 as it does a 9". I'm sure anyone who has done them would agree.

It is the same money to set up either diff. The 9" is FAR more expensive than the D60.

I would have to look up pinion diameters but I've never broken a D60 pinion.
The D60 takes LESS HP to drive with LOWER gears (higher numerically) than the 9". This is NOT linear. As you go to lower gears the 9" starts to eat power like mad. The push is 3.90. At that ratio, they both take the same power to turn. By the time you get to 4.56, the 9" is wasting power. For years I ran 5.57 gears in my drag car. The gentleman who taught me how to set up diffs told me, in his personal testing, at that ratio, the 9" was eating 35-40 HP. And he actually tested them. That's why I used the D60. It was cheaper, just as strong, and took less HP to drive.


As for ease of replacement, that is the biggest bag of bullcrap I have ever heard. I can't hardly get a racer to pull all 8 spark plugs, let alone drop a 3rd member to change gears. And what about cost? You want me to think guys that [censored] about the cost of synthetic oils are going to front for 2 9" 3rd members? A Comp guy probably. A fast bracket guy maybe. But the rest of us? Fat chance.


In the end, I really don't care what diff anyone uses in their car. It's their stuff and their money. But what eats my draws is the general lack of knowledge about this stuff out there. It's sad that for DECADES the same crap has been passed around as truth.


And if Dr. Diff sees this, I would love his input and thoughts.

If you really looked at what I wrote down you would have found that I said you lose more HP running through a 9" than a 60

The pinion in the 9" is set lower coming out of the axle which allows you to lower the car over the driveshaft EASIER without cutting the driveshaft tunnel.
This is done mostly with very fast cars which start getting very low.

It is my experience that the 9" is lighter if you compare stock axle to stock axle. Even with the 9" gussetted.

The 9" ring and pinion can be set in the 3rd member on a bench without removing the rear axle.

The Dana 60 requires you set it up under the car if you don't want to remove the whole axle. Which, if you don't have a lift is a bit harder.

Plus I forgot to mention what others have said. It's easy to change 9" gears if you have extra 3 members around.

All that being said I would still prefer a Dana 60 under a mopar.

9"=Ford=

Chebby didn't have any real choices when it came to differentials so they may benefit from some Phord parts. But Mopar has always had enough superior diff choices that you don't have to resort to running Phord parts.

If you like putting Phord parts on your Mopar, it's yours, go ahead. But it is not necessary.

I'd still take the 9", I like being able to swap out the 3rd member, definitely not from a lack of knowledge. It's all personal preference, just like all the other threads about rearend ratios, overdrives, etc.

My thinking has always been that if your engine has enough torque to light up your rear tires,,,particularly with an auto trans and the torque multiplication they provide,,,that going to a lower rear end ratio buys you zip in performance.

In other words if you got a 3:08 and your motor will light your tires when you stand on it, going to a 4:10 helps not a wit. However if your plan might include some drag racing with some traction oriented tires to be swapped in as part of the deal, then yes a lower gear will usually pay dividends. I did not note what your current ratio is,,,however if slicks are not part of the plan,,,a 3:23 or even a 3:08(or whatever is close in the Mopar world) could be just the ticket,,,great on the highway and at the stoplight.

Build you motor,,,I suspect it will be a torque monster,,,keep your current gears,,,if you can light up your tires,,,save your rear end budget and spend it on something else. If the car is a slug,,,with the engine you are building, likely not,,,than think about overdrives and lower rear end ratios.

Some years back I replaced the stock 3:54's in my 3 speed push button torqueflite equipped 300 B with a 2:92 rear axle. With 3:54's at 80 mph sounded like the solid lifters were swapping holes. With 2:92's sounds like a Bentley. The torque laden dual 4 barrel 354 Hemi cares not a wit about the swap when leaving a stoplight.

When does the ground war begin?

Please tell me where I can get a new D60 3.08 gear!? Everything I have seen so far shows 3.54 is the closest that's currently available.

Same here, never see anything below a 3.54 for a Dana.


Nice car Sxrxrnr!!

Probably referring to the D61 3.07 gear that came in some Ford trucks and all 1st Gen Cummins 3 spd equipped Rams. I think I've read that a D61 gear can be put in a 60 housing with a spacer? Or it might be the other way around, 60 gear in a 61 housing with a spacer

While I have never owned a ford 9" rear end, summit sure shows a wealth of attractively priced components with gears going from 3.00 and up.



The other way around, the 61 will accept 60 r&p with a spacer from what I've read. In any event, I don't think anyone makes D61 gears at all.

Except Dana/Spicer, right?

One thing about the Chrysler vs Ford debate. As there were many many more Ford trucks built with Dana 60s than any Mopar. or probably all of them added together, it would be equally as (im)proper to call a Dana 60 a Ford rearend.

In theory, the larger the gear ratio in a hypoid gearset, the more power is eaten by friction. So it'd be a better choice to run a 1:1 Top gear and have deeper gears in the transmission. That's what the Doug Nash 5-speed was all about.

Also, in any gearset the larger the gear ratio, the weaker the gearset. Right around the 3.00 mark is when it gets tricky. To get a pinion gear strong enough for a 3+ gear ratio the transmission designer increases the distance between mainshaft and countershaft and the transmission gets bigger and heavier. All of the gears increase in diameter plus there's more case.

It's my opinion that around 10:1 total gear ratio is necessary to start a street car in any street situation. That'd be a 3.09 First and a 3.23 rear gear. My first car had a 3.09 First and a 3.08 rear gear and that was okay but I didn't live in hilly territory. Even so I could have made it work.

R.

Agree with above.

Another thing to consider is that for
durability and low noise
gears that have a
"Prime Number"
of teeth are better.

Actually, I have not seen a set of 3.08's for a 60 since 1983 when I bought the 5.57's for my car. I remember thinking who would use that gear? It's worthless to me. If they don't make it today, it's because no one wanted it.

I will never understand how people calculate gear ratio, especially the auto guys. They gear too tall and force the converter to slip and then say the engine rev's too high. Obviously, I don't care for automatics either.

I can't think of a single use for a 3.54 gear for a muscle car oriented set up. It's not a camry.

Please let all the manufacturer's know which parts you don't approve of so they can stop production immediately! And feel free to make a list of how you want us to build our cars, you crack me up.
Hopefully you'll be cruising around my neighborhood so I can show you how well 3.23 gears work with a stroked big block.
Not to mention the maroon colored Dart here on Moparts that runs 9.50's with a 3.54 gear. I hope he built the rest of his car to your expectations. Are you running less than 318 cubes with your 557 gears?

By the way 2ndopp, I think you'll be alot happier taking your 360 to 408 cubes vs. doing a full swap in to a 440. I'm a big block guy but it takes alot of time and money to completely change over, usually you're talking about changing radiator, engine mounts, headers, different tranny case, maybe converter, engine accessories, etc etc.

I don't care what you do. You get butt hurt awful easy.

If you think a 3.55 is a LOW gear I can't help you. Get a life.

Not butt hurt at all, and my life is amazing. Just trying to point out bad info, not everyone needs 557 gears in their street car and street gears aren't just for Camry's. Have a great day!

What is the lightest weight two speed rear differential available,
like those in 1980s Mack midliners
or the smallest dump trucks?

In past posts we have discussed the short lived two speed Dana 60 that was available one year on Mercury Cougars.

As far as I know, 2 speed rears are medium duty truck only... like the midliner or an old Dodge D600. Cars and HD trucks get it done with the transmission or transmissions.

Ford offered such in the mid-40's and early 30's across their product line.


http://www.flatheadv8.org/columbia/columbia3.htm

Lol.

So Bonny and Clyde could have had a two speed rear axle on some of the many Ford V8s that they liked to steal?