Automatic Transmissions

[BlownMGB-V8]

Are they ready for Prime Time?

The one used for the last 3 years in the Lexus IS-F seems to be. 8 speed, converter lock up in the top 7 gears, dual pattern dual mode shifting, accepts paddle inputs, 100 or 300 millisecond shift time (depending on manual or auto mode), throttle blip on downshift, and a stand-alone controller that takes inputs from the drivetrain controller. This one has a narrow pan, 4 clutch sets, 2 disc brakes (upgrade from brake bands) but uses a unitary case and bellhousing.

The one used in the IS/GS 350 is similar but a 6 speed and has a removable bellhousing.

Anyone know what the latest and greatest from other manufacturers are?

JB

[roverman]

Jim, I don't know how many ,"others", have their own, stand alone computer. I make a bell housing to fit the,"Toy-Borg", 4spd/od w. lock-up. Designd by BW. and built/used in Celicas/pu's, and needs no computer. I selected it for cost/availability and it fits well, in the "little" Buicks and Old's. If you find just the right trans, but it's integral bh., and if it has a round/concentric counterbore, that the front pump/stator support plugs into, this may allow you to cut-off the old bh. This makes it easier to add engine fitting bh. I believe the CVCT has advantages, such as built by "ZF" and optional in some bigger Fords like the "500", but didn't catch-on in the larger cars. roverman.

[hoffbug]

Im going rather old school  with a 2004r. I like their gear ratios better than a 700r4, have a lockup converter.. And can run without a computer... With some modification  they stand up in sub 10 second Turbo Buicks they should be fine in my Aluminum V-8 Vega.

[BlownMGB-V8]

I'd like to kinda push the envelope a bit here. The old automatics weren't called "slush box" for nothing, but some of the newer ones will shift very fast. Several companies (including TCI) sell stand-alone controllers so that is not a problem. (they even have a 6 speed based on the 700r4) I have a 2004r but don't think I can get the shift characteristics I want out of it. If I am going to have to adapt a bellhousing I may as well start with the best tranny I can put in the car. Looks like it might take a lot of research though.

JB

[joe_padavano]

"Several companies (including TCI) sell stand-alone controllers so that is not a problem."

No, but the $1,000 price tag is.

"(they even have a 6 speed based on the 700r4)"

No, they have a six speed based on the 4L60E.  And the "six speed" simply splits first and second by using the OD gearset to get the two additional ratios.  The problem is that the OD clutch pack is not designed to live under low speed torque.

"I have a 2004r but don't think I can get the shift characteristics I want out of it."

What are you looking for?  The Turbo Buick crowd runs 9 sec quarter miles with these transmissions.

[BlownMGB-V8]

Maybe I caught you on a bad day Joe? Look, I'm not asking for a miracle here, just something a little better than the same old white bread. TCI isn't the only controller option and their 6 speed was just an example, and not the one I'd pick. The 2004r is a fine transmission, especially if you want to drag race but I don't. I want to shift up and down while going in and out of corners. For that it's pretty lackluster. 4 gears and a lock up clutch is adequate, and *maybe* proper tuning by an expert can get it close but I've talked to several of these experts and they all ultimately begin talking about the 4L60E. Which is OK, but it doesn't fit my block and the pan is so wide I'd have to cut the floor. I'd probably have to cut the floor with the 2004r also.

It just happens that there is a whole crop of automatics out there that use a narrow pan, and those should all fit the car without body modifications. They also come in flavors of 5,6 and 8 speeds so the only real issues as far as I'm concerned are matching the block, price, availability, and the controller. Most of the ones I've looked at lately have a "performance" shift option of some sort also.

So taking these problems in order of importance, first matching the block. Some come with a detachable bellhousing which is great. I can put that on the mill and make changes. I can add metal for bolt bosses with the tig welder. I should be able to make that work. The ones with a unitized case will need an adapter plate of some kind and probably standoffs on the torque converter. Price, availability and controller, I hope to find a good one in a junkyard along with the wiring harness and the controller. For the shifter, again the junkyard may provide the solution.

At this point I am just trying to get an idea which ones might make the best choice. I suspect the 8 speed in the Lexus IS-F is going to be scarce and expensive, and it has a unitized case.  But Lexus is in their 4th year of production and that tranny is also used in the entire 460 model line. The ZF 8 speed hasn't been out long enough to have much luck finding one, though it does look like a good choice. The Toyota/Lexus 6 speed A761E and A760E may be the right choice due to the separate bellhousing. But what else is there? I know GM has a 6 speed but I've heard it's had teething problems and that seems to be a habit with the American designs (early 700r4's for instance were not good) and the controller may be integrated into the primary PCM. Pan width may also be a problem. No clue what Ford or Chrysler may have, or for that matter any of the other auto makers.

So that's where I am. I'll probably visit the junkyard at the end of the week, and perhaps a local tranny shop also so I just want to be able to hold an intelligent conversation with them when I do.

JB

[hoffbug]

so essentially you are looking for characteristics of  a clutchless manual transmission.

[mgb260]

Jim, Also check Ebay on Lexus trans. Also car-part.com for regional wrecking yards. I'm sticking with the AW4/A340. It does everything I would want and has worked repeatedly at low 9 second quarters.Of course that is with Kevlar clutches and bands and other mods. Stock it is about the same as a stock 700R4/4L60.

[pcmenten]

I'll throw this out there; the Rover uses the ZF 4hp22 and its bellhousing bolts onto the BOPR block. I was going to get some parts off of a Volvo version to convert the transmission tailshaft for a driveshaft instead of a transfer case. It is computer controlled. But, frankly, I've been a little preoccupied lately and haven't gotten to that project.

I see that there is a ZF 6hp26 with a capacity of 443ft-lbs., used on BMW and,...

wait for it...

Hyundai Genesis. Yikes!

http://en.wikipedia.org/wiki/ZF_6HP26_transmission

[mgb260]

Paul, Rover pattern is 215, Jim B. is looking for newer, 64 and up BOP for his 340. But, if the ZF 6hp26 has a separate bellhousing he would be interested. Or like Art (Roverman) said in earlier post, use front pump pattern and cut exsisting bell off.Use that pattern to bolt modifed BOP bell to.

[roverman]

Jim B. ?  Sounds like your building a Formula1 version of an MGB and manual would be more efficient. Perhaps better selections of ratios and reduced parasitic.  roverman.

[mgb260]

Art, on the MGB Experience board there is a thread"New small V6 automatic"  Aisan-Warner Jeep AW4 91-96,Cherokee 2WD same as Toyota Supra A340.Separate bellhousing.Jeep 2.5 and Isuzu V6 bellhousing is same as GM 3800 V6,Caddy 4.9 V8,2.8,3.1,3.4 V6.With Advanced Adapters AMC Turbo400 adapter with 4.0 bell can fit Chevy,BOP V8.Toyota 3.0 V6 and Isuzu V6 have 2800 stall converters.Which hold up to twin turbo 600-800 HP, low 9's if built. 4 speed O/D. Solenoid manual shift either stick,pushbutton or paddle shift.

[BlownMGB-V8]

Right now I'm trying to find out how much the AA80E (8 speed) and the A761E (6 speed) sell for in the junk yards, when you can find them. Any assistance appreciated, I once had a link for a u-pull search...

Anyway, apparently the AA80E shifts 40% faster than the A761E, possibly an advantage worth pursuing, but much will depend on cost and availability. The separate bellhousing on the 761 is a significant advantage. Both are in the ballpark on torque and HP. I think a dual pattern stick is probably the way I'll go but won't rule out paddle shifters at this time.

An old drag racer suggested a Lenco with a torque converter, but somehow I don't think it'll be what I'm looking for.

JB

[ex-tyke]

Jim, Here's a link to some US & Canada bone yards.

http://car-part.com/

[roverman]

Jim B, If you must have the 8 speed, don't rule out ,cutting-off the integral bh., or just make an alum. adapter, like Dand D or Kennedy does. Compnies like "Reid and JW Perf. Trans", as listed Jeg's, make separate bh's for autos, that were integral. Not a big. I know you can handle it. So I guess a paddle shift stick is out ?  roverman.

[BlownMGB-V8]

Haven't completely ruled it out Art, and I am due for a new steering wheel sometime so who knows?

I've done tranny adapters before. Advance Adapters still stocks my Blackwood Labs IH-SV series engine (265, 304, 345, 392 cu.in.) to 700r4 adapter, although I gave up on promoting them about a decade ago. Wasn't a real brisk seller, those IH guys are double cheap. I'm not badmouthing them, they all know it. So if it comes down to it, I can make an adapter but it is not an easy task. Still, for the right deal on the tranny it might be worth it.

Graham, thanks for the link, drew a blank on the 8 speed. I'll probably have to send out a general parts request. I'd really like to take the "no compromises" approach but at what cost? If it means not driving for another summer I'm not sure it's worth it.

JB

[roverman]

OK, and your against a Ford 500-(by ZF)CVCT because....? Shifty but good.  roverman.

[BlownMGB-V8]

Because I don't want to feel disconnected from the mechanical bits of the car. I like knowing at just exactly what point the tires will break loose. I like having the road speed positively linked to the engine speed. And I expect this engine to have a remarkably broad power band. Really, a proper 4 speed is about all I need but without the clutch. Heck for that matter it'd do just fine with a 3 speed. But as long as I'm going to the trouble I might as well get it right.

So let's see, if one tranny shifts in 100ms but does it 7 times while the other only does it 5 times but is 41% slower.... figger, figger, figger.... yep, the 8 speed nudges out the 6 speed by 5 milliseconds. Better get the 8 speed, fractions add up!

JB

[roverman]

Ok, some would consider "chain", fairly mechanical. If your driving 10/10's, the tire/tires will break loose more likely when they feel an "up-set", ie. conventional shift/lift/stab of the throttle. Good Luck, roverman.

[BlownMGB-V8]

Turns out the A761E six speed is probably the best choice, but the transmission control module (TCM) is not attached to the outside of the transmission case in any application I have found so far. (FWD it is fairly common). A low mileage tranny can be had in the $1000-$1500 range whereas the 8 speed runs close to 5 grand. Shift firmness is controlled by pulse modulation of the shifter solenoids and the valve body does not use accumulators. There is apparently no external line pressure control. The TCM in most RWD applications is incorporated into the ECM but a FWD TCM may work. The A761E is used behind the V8 engines whereas the A760E is used behind the V6. This probably means different gear ratios and possibly some strengthening of the 761, and likely different shift parameters as well. Finding a V8 FWD application seems to be the best option for a TCM, perhaps a Toyota. Then comes the question of access to the controller for programming the shift characteristics.

I am attempting to acquire a low mileage 761 at a good price and will know more once that is done, particularly regarding size, shifter requirements, connector types and such.

JB

[mgb260]

Jim, Is the FWD tranny  longitudinal or transverse? Are you going to use the RWD tranny with FWD control box?

[BlownMGB-V8]

That's the plan Jim. I expect transverse FWD is the norm but if it is the same tranny in a different case perhaps the FWD module will work. The transmission is supposed to be here Monday. I found a yard with a large supply of them and was able to make a deal for a low mileage unit delivered to my door for about $750 which I consider to be a very good price. The guy says they just don't break. He sells all the engines he can get to dealers but the trannys just pile up and he basically asked me to name my price. It will come with the pigtail for the electrics and once I look it over I'll contact him about possibly some other components, odds are good he can come up with a module for me, maybe a shifter, and I'm very curious about the  coupler used immediately behind the transmission on these cars.

JB

[mgb260]

You could weld up a hybrid coupler,like the Lexus splined part front/u-joint yoke ,my guess, a weird 3 bolt cv type setup instead of u-joint.Ratio-tek has a valve body kit for A761.

[BlownMGB-V8]

I saw that kit and it immediately made me wonder how hard it is to modify the shift parameters in the TCM. Ours is not a drag racing application so I'm not sure the shift kit is appropriate. I will likely try the stock set-up first, then look at modifications. There's a guy at the Lexus dealer I can ask about tuning when the time comes.

I will have a stationary driveshaft due to the Jag IRS so flex joint design is pretty wide open. Basically anything that will allow small lengthwise fluctuations will do fine.

JB

[roverman]

Am I hearing correctly ? Monster motor meets slushbox ?  How much torque ?  roverman.