Engine and Transmission Tech

"



Edited 4 time(s). Last edit at 03/11/2012 04:28AM by kill r b.

I have exactly zero experience with 2 speed axles. I know they use them on trucks. My impression is that they would be heavy and large. Might get away with it on an IRS though where it would be sprung weight. Due to the extra size needed, it would probably have to be a custom build and you might lose the battery boxes and/or need a custom gas tank.

Jim

WHY?

I've seen the old Columbia 2 speed rear ends for early Fords. Not much larger than the standard center section but as Jim said it did add some weight. All it consisted of was a planetary gear set between the ring gear and the axle gears to achieve an overdrive ratio. Not the strongest thing you'd want behind a modern performance engine but certainly satisfactory for the early Ford flat head V8s. I think that adapting a planetary gear at the output of the trans would be much stronger and achieve the same result without adding the unsprung weight unless you're using an IRS design.
By the way, the Columbia design had the axis of the planetary gear set on the same axis as the axles not on the pinion. Here's an article in Hemmings about the design. [www.hemmings.com]
They also had an over drive unit that mounted to the rear of the trans on some Lincolns as you mentioned.

Gear Venders make a O/D/U/D unit that mounts behind tranny. It is used in muscle cars and motorhomes. You might be able to modify a small 4X4 transfer case also but both would require major tunnel surgery. Might not be too bad if mounted as far rear as possible.

If I am reading right you are actually talking about 2 different rears. The old Columbia 2 speeds were stock in '30's Ford products and are highly sought after and really expensive. They are operated by a switch if I remember right. Then there are quick change rear axles, these are the ones that you would need to get under and swap the gears around.

A 2 speed axle would be pointless in my opinion in a newer vehicle. A quick change rear would work if you have a car that you would want to race on the weekends and cruise during the week.

Both options are expensive. A quick change can be purchased new if you want to spend the money. In my opinion a overdrive trans would be the best option.

Dan, These units faded from prominence, like wood spoke wheels. Much better designs came along. Today, good value 5and6 speed transmissions and transaxles are readily available. They are lighter stronger and much cheaper. Cheers, roverman.

Or, there is always the option I picked for my RD, this 8 speed automatic has a four something 1st gear and two overdrives, I think an 8 something and a six something. That pretty well spans the gap.

Jim

Jason, you must realize that the rear gear on an MGB is 3:90. The best 1st gear in an easier adaptable trans. is a Ford or Chev 5 speed. The standard Mustang replacement box has a 2.95. You can't get gears without paying through the nose for a custom gear set, installed. Chevy had a 2:79 I think, but still to low a gear for the street. So if you calculate that and the overdrive ratio the stock MGB is still under geared. Any way you do it will cost bucks. Besides that I hoped to use a powerglide because it is simple and small compared to the 200 4R etc. It doesn't require a cooler and it will fit without wrecking the metal work .I would think someone would make a lock up converter for it since the hot rodders prefer the PG. Problem is the first gear in the PG combined with the 3:90 rear gear gives an over all ridiculous ratio of about 12 or 13. I would like to try using an intermediary gear box as Jim N spoke of it.

Bill and Jim, thanks for kicking in here. I had forgotten about the intermediary box that Jim N. spoke of.

Jim Nichols is that the name of the company GEAR VENDORS?

DKW BCC



Edited 1 time(s). Last edit at 03/10/2012 07:01AM by kill r b.

Dann, Gear Vendors is the brand,sometimes you can find them used at truck wrecking yards. I thought about the same thing to make my 4 speed Aisan auto 8 speed like Jim B.s. I was thinking of the Suzuki Samurai or SideKick tranfer case mounted backwards. Samurai low range is 2.28. That would make the 3.91 rear a 1.71. Gear Vendors are .7 like overdrive on a 5 speed.

Thanks Jim and I also appreciate your thoughts on this subject. Not to be a party pooper but if you run helical gears backwards wouldn't they tend to climb out of the case or you speaking in other terms. You really have me interested here.

Dann BCC

Dann, They won't climb out of the case but, now you got me thinking. I know a differential if turned won't be as strong because the pressure is on the smaller coast side of the curved gear rather than the longer drive side. That said, some maufacturer's get away with it in front 4X4 applications(Jeep,Toyota). Ford went reverse curve on their front axle so it is a heavier duty unit. The helical gears are mainly to prevent noise. Though the angle of the gear may pull less oil up(ATF) for lubrication, you would use a heavier grade of oil(Synchromesh) and run slightly over full. I don't know how Gear Vendors do it but I heard that reverseing it is how they switch from overdrive to underdrive.Maybe they have straight cut gears.

I ran a Muncie backwards once in 1977 between an Olds 350 and a Toyota Landcruiser 3 speed. It was awesome. 24 forward gears and 8 reverse, nearly half of which were overdrive. It would go faster in low range than a stock Landcruiser would in hi range, which meant, coming off the high trail onto gravel there was no need to stop and range up. I could go straight to the highway and keep right on moving. It worked very well until the bearing retainer nut on the muncie input gear (which was then the output shaft) backed off from being run in the wrong direction. Then the whole works locked up, and in youthful frustration I threw in the towel and traded it off. I have had many regrets over that one, it was a rare drop-tailgate '66 rag top.

My main concern with these schemes is that there just isn't enough room without seriously hacking the body. That's why I find the AA80E so appealing. It fits in the tunnel without any mods or hammer work. The down side is basically two issues. Electronic shift control (this will be resolved), and mating it to the engine of your preference. It fits the Toyota UR series engines (4.6, 5.0, and 5.7L alloy block DOHC) which would be a very tight fit into the MGB. If someone pulled this one off it would be an amazing swap, but undoubtedly they would have to seriously hack the front of the body to get the engine to fit. I'd love to get my hands on one to play with it but the engine is still seriously expensive. The tranny uses an integral bellhousing too, so the only way to mate it up to another engine is with an adapter and they still aren't common enough that anyone is making adapters yet. In time that may change, i think they've only been around for about 4 years.

But the 8 speed is serious overkill any way you look at it. Who needs a 4.596:1 1st gear? You could run a straight 2:1 axle gear with that. Plus a .824 and then a .685 overdrive? I'm really not sure what they were thinking when they selected these ratios, except to take full advantage of the tranny's superior shifting speed. I mean, I'm pretty confident you could couple it to the peakiest engine on the planet and stay in the powerband no matter what. Ever since I selected that tranny I've been worried about my 3.56 axle gears. Go what, 5 feet before shifting to 2nd? Forget 1st entirely and always start in 2nd? (9.7 overall) I mean, I can see where 1st might be good for parking lots but not much more. However, the double overdrive should be handy. In practical terms it makes more sense to go to something like a 5 or 6 speed, especially when you throw in the effects of the lock-up torque converter. I've driven a 6 speed Nissan rental car and they are quite good. Plus you can get those with removable bellhousings like what Jim N has been playing with. When we get these cars on the road I think they will change some minds about the old auto/manual argument.

You might say an automatic does not suit a traditional sports car. True enough. But aside from the visceral feel of banging through the gears there isn't much difference these days. Hard to pop it out of gear and rev the engine of course. And this particular line fits the tunnel. So a 4,5 or 6 speed with a removable bell and lock-up would seem to be the perfect compliment. Admittedly I went overboard with the 8 speed. So? What else is new?

Jim

I started out just kidding about the Samurai transfer case. Now looking at it more and more research it sounds better except one problem besides hacking up the body. Overdrive ratio would actually be .64 due to gearing in the transfer case. You could remove front output gear assembly and tig weld flanged plates to make it more compact. Here's the rub,non-synchro so you have to stop to put it in OD. Maybe double clutch and clunk in at low speed. Here is a pic, red plug is where manual shifter goes so you would have to have remote linkage also.Probably like Corvair with long rod going forward.




Edited 4 time(s). Last edit at 03/11/2012 07:24PM by mgb260.

Dan, Aisian Warner 3040 L,(od) This is a compact 4 speed auto, 29% od in 4th. Used in Volvo's, Toyota cars and trucks. Adequate for most smaller V8's, removable bell housing, narrow pan, about $200. at J.A.P. importers,(low mileage). If you select a trans with downshift cable, needs no computor. A Rover BW. automatic bell housing will get you "close" to a bolt-up situ. Good Luck, roverman.



Edited 1 time(s). Last edit at 03/10/2012 04:11PM by roverman.

Just thought that I'd throw this out there. I know that a motorcycle is not a car, but...

A few of you may recall that circa '80-'81, Honda made a bike called a CB900 Custom (and its replacement, the CB1000 Custom).. These air-cooled inline fours featured two shifters for two seperate gear boxes - a normal five speed transmission plus an additional two speed that acted like a truck's two speed rear. This offered two different ranges in which to operate the five speed transmission.

Before long, they realized that this was not only more complex, expensive, and trouble-prone than they wanted, but that it offered no real advantage over what they used instead. The '82 and later V-four Magnas and Sabres that followed had just one transmission - it had a sixth gear overdrive. Not just was it a six speed, but that top gear dropped the revs significantly for cruising the highway (and made it possible to reach ridiculously extra-legal speeds - ask me how I know - I assume that this is why they discontinued the practice altogether!)

This setup proved to be much more durable and simple.



Edited 4 time(s). Last edit at 04/06/2012 06:34PM by highmileage.

Dann, hotrodders don't prefer Powerglides. Drag racers do.

What was the Cruise o Matic that came in the 66 Mustangs was that an over underdrive unit? I remember a friends mother had one and he said it had 2 sets of 3 gears, I told him he was full of it but I thought I would ask y'all in your infinite knowledge.

> What was the Cruise o Matic that came in the 66 Mustangs was that an over
> underdrive unit? I remember a friends mother had one and he said it had 2
> sets of 3 gears

The Cruise-o-Matic is a convential 3 speed automatic. I think he's confusing
Ford's Green Dot Dual Range shifters. The Dual Range shift indicators had
two ranges of designation on it. The designations were: P, R, N, Big Dot
(instead of D for Drive) a small Green Dot for the 2nd range and 1 or L (low)
for first gear. If you put the shift lever in the small green dot, it would
shift conventionally (1st-2nd-3rd). However, if you put the shifter in the
big dot, it take off in second gear. This was safer in slippery conditions
like ice and snow. The C4 in my 1966 Mustang fastback was this way but I
swapped it out for a 5 speed Tremec TKO.

Ford did work on an overdrive (4 speed) automatic transmission based on the
Cruise-o-Matic back i the early 1960's. The overdrive gear was 0.67:1
and was integrated into the gear set, not an add-on. 1st through 3rd were
the same as the X version of the Cruise-o-Matic and there was a lock-up
torque convertor. Ford dropped the XT-LOD design in the mid-1960s before
it made it into production but it was later revived and became the basis
for the Ford AOD (automatic overdrive) transmission introduced in 1979.
The original design lacked a dampener in the torque converter but that
was added to the AOD. The AOD valve body also retained the ability to
manually shift if you knew the sequence.

A friend also had a JATCO (Japanese Automatic Transmission Company) built
version of the Ford C6 that had some sort of overdrive or lock-up.

Ford did advertise a Dana 2 speed rear end for the Mercury Cougar.
There were some period articles on it but it was never placed into
production.

Hone Manufacturing also produced the Hone-O-Drive. Hone made several
versions of their overdrive, including versions that bolted to 8"and 9" Ford
rear ends, a version that bolted in place of a transmission tailshaft and a version
that spliced in the middle of the driveshaft. My dad's 1969 Fairlane Cobra that
I inherited has the type that bolts to the 9" rear. It stood up to a bored and
stroked 427 side oiler Ford so appears to have been a stout unit. It was
originally a cable shifted unit but dad converted his to air solenoid shift.
The Hone units were also an option on 1966 Shelby Mustangs.

Dan Jones

Well engineered 5/6 speed t-axles are readily available as low mileage used units from ebay, craigslist, etc. For example, 2003 Porshe Boxter Spyder 6 speed, in excellent condition, garranteed = $1,350 outright.1/2 shafts for same $200.Shifter cables(2) = $100. The neat thing about t-axles is your geting a trans and differential for about the same $'s as a 5/6 speed trans, and they always improve the weight distribution. The deals are out there. Good Luck, roverman.