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Volvo Automatic Discussion (part 2)

linuxman51

Railspeeder Enthusiast #1
300+ Club
Joined
Dec 25, 2002
Location
mont, AL
We'll refer to this as "beating a dead horse", since the first inception of this was called "polishing a turd"

Referencing this thread of course: http://forums.turbobricks.com/showthread.php?t=64408&highlight=polishing+turd
Started by Aaron(sp?).

At any rate, as some/many/none of you know, i've yet again ventured back to the venerable, but ostensibly weak volvo automatic.
Namely the AW71.

Since the writing of this article, a few neat hacks have become popular, the somewhat legendary valve body hack, which comes back into and out of fame (and has been around longer than Aaron and probably myself were members of this forum), but most notably the 'Accumulator mod', which essentially locks the accumulators to reduce shift time (and both combine to really reduce shift time).

Building on what aaron has started, lets open this discussion on a slightly more technical note, and start from the get go with the box as a whole and see if we can't work forward from there.
The ATSG guide for most of the pertinent A series transmissions can be found online here: http://www.pbase.com/sam3481/aw_manual
There is an older volvo specific guide which can be found elsewhere with a cursory search on the forum, and its host might (hopefully will) grace us with his presence and insight.

After spending some time thinking about this issue, some degree of trial and error and mild success, I've decided to commit a little more money to my own project in an attempt to see what can be done to get one of these transmissions to hang on to some serious power for at least a little while. Since I personally tend to spend most of my volvo quality time either in the driveway or at the drag strip, I'm not concerned in the least with longevity, within reasonable bounds (and I'm also a fair bit ahead of most in the power output side of life, so I would imagine what can take my level of use and abuse for a little while will serve many others for quite some time).

So let's start with the stipulations and reasons therefore (and i'm going to borrow heavily from aaron's thread. Consider it a prerequisite for this thread, so get to reading it and come back):
1) I would rather not increase line pressure unless we have to, and then, only a moderate amount. Reason: Cavalier increases in the operating pressure will blow the seals out in the clutch engagement pistons, and this would be considered counter-productive. Besides, higher pressures beget more strain on the pump and more power robbed from the engine, and enevitably this will result in more heat. Heat is a bad thing.
2) While it would be really nice to use "all volvo" stuff, I'd much rather be smart about it, if we determine that we can stuff the C2 carrier from a higher output unit in the volvo unit, lets run with it.
3) We're not getting into full swaps here, the goal is a unit with volvo dimensions and similar linkage that "bolts in".
4) Valve body is fair game, I disagree with aaron on this, I don't feel that flow modifications inside the VB will greatly increase the load on the pump (aside from shimming the hell out of the main pressure relief valve).

Brainstorming:
Aaron mentions in his thread something about slow disengaugement/engagement of the brake clutch packs, I'm thinking something along the opposite lines, i.e. weaker/less springs for the main clutch disengaugement. The idea here being that more springs resist pressure and slow the engagement of the clutch and simultaneously reduce the overall clamping pressure being applied by the engagement piston..

Alternatively, by swapping springs with the brake clutches, perhaps we can kill two birds with one stone. Thoughts comments?

I've been digging through the power flow diagrams for the aw-7X transmissions (oh by the way, if you haven't already figured out they're all essentially the same, minus some key differences in friction material and perhaps amount of friction material i.e. number of clutches, you needa go back and study some more).

Some background info from the green book and nomenclature (from now on lets try and keep with whats in the ATSG/Green manual, since there isn't a "gear set" per-se, just a series of locked and unlocked planetary gears, however I realize that generalizations will be needed for the sake of sane discussion, but when dealing with specifics, lets try and keep to the manual).

Primary Clutches:
C0, C1, C2.
C0 can be thought of as "overdrive", however this is only partially true: the only 'gear' that C0 is NOT locked up is overdrive,C1 and C2 will likely be the focus of most of our discussions.

Brakes:
As stated in the previous thread these are basically the same thing as brake bands in other automagics.
B0 can also be thought of as "overdrive" as it locks when C0 unlocks to overdrive the transmission.

There are two Free wheel locks, these are basically one way clutches, and are subjected to most of the brutality the transmission will see, from the green book, when in first second and third "the highest power is transmitted by the freewheel". So, also fair game.

I will attach an image here when I find a suitable diagram/get my scanner back to show the approximate locations of the above components in the transmission.

So. Open. Lets talk. And I don't care about a gm transmission, if I want one I'll swap in a t56.

***NEW INFO***
We can narrow down changes from the AW372 and 71:
C0 Has two clutches instead of one. Swap the uber thick steel for a steel and clutch.
C1 and C2 are identical to the aw71
B0 has one LESS clutch than the volvo (however I think this is more to discourage towing in OD)
B1 has an extra clutch, this requires a different clutch carrier than that which is found in the volvo. It is interchangeable. You want the part number, go dig one out of a jy your damn self.
While you're there get the C2 carrier, the volvo one doesn't have enough depth capacity.
B2 is the same
B3 is the same
The middle/rear planetary is different, I believe this is more related to a lower ratio for towing than a strength issue, however if one wishes to use this, you will also get the privilege of swapping out tailshafts or making a custom driveshaft. (one is far easier than the other)

The lock up and non-lockup pumps are different.. the lockup pump is larger internally. The ports are the same on both stators, however you CANNOT use a non locking converter with a lockup pump.

Regarding the difference between the aw70 and the aw71. This is an oft debated topic that no one seemed to have any really hard info about. Well here's (most) of the skinny:
Different pump and OD housing (at least up until 88/89). The pump 'intake' is bigger than that of the 71/72/43 pumps, however the OD housing flares out to accomodate this, the reality of the issue is that due to design (either poor or other) the feed for B0 just 'happens' to come up in the middle of what would be the intake. So the net result is a reverse funnel of sorts. Not sure if this is a good thing or not, or if machining out the intake to flow more would be of any help at all.
Overdrive brakes are smaller on the aw70(same size as the other clutches), B2 piston has 8 fewer springs than b2 in the 71.
B1 piston has the same number of springs.


The valve body & governor are likely to be a bit different as the aw70 runs different line pressure than the 71. The other internals back to B2 are the same (same count, etc).
Externally the valve body, case, etc are the same, so the usual aw71 mods apply to the aw70, and it seems likely that the gov and vb swap would result in one effectively having an aw71. If there are spring differences in the clutches and brakes, its not immediately apparent, I might take a closer look later this week.


The gear ratios between the aw's of this series (basically the A4X) are controlled by the size of the planetary gears & these are all pretty much interchangeable, provided you get the correct carrier with them.

Failure points are somewhat random so far in the transmissions i've examined, the most common seems to be B2 and B3, with C1 and C2 following closely, however I've also found a destroyed B3 pack, and know of at least one instance where B0 was starting to let go.
C0 for some reason doesn't seem to be failure prone, however I would not hedge any bets on this. it might be possible to retrofit a different shell into C0 to get more than two clutches with reasonably sized steels in it, that will, however, be an exercise for the reader.

As for differences between the 71 and 72, it would appear on the surface that the governor is the same, the valve body will certainly be different to accommodate the lockup converter (among other things it has an extra valve).
 
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here's a quick one, anyone know why there would be a "spacer" ring in the front clutch assembly?
74556317.jpg

(middle of the image, the 'thinner snap ring')

After close inspection of the guts on the table, one can conclude that:
The clutch can pass in between (assuming it doesn't get hung up) however while the snap ring should be thinner than the clutch itself it might still act as a stopper. Its on the wrong side of the closest steel band to serve as a stopper for the engagement piston, and regardless of clutch engagement or not, the rear clutch hub will spin at the speed of the front clutch hub since its locked in place with a snap ring and the tangs.
 
Info from the green book regarding Valve body components and their (basic) functions: (picture to come later, for now refer to the ATSG link, pages 64-67 if you're looking at the file names)
Gear selector valve: Operated directly by the gear selector mechanism, the valve determines the position (P,N,D, etc) in which the gearbox operates. The valve is supplied with oil at line pressure and distributes it to the appropriate passages according to the position selected. The governor is also supplied from the gear selector valve. The pressure used in the actual gear shifting operation (i.e. engage clutches and brakes) is low when then load on the gearbox is low, and vice versa.

Primary regulator valve: This modifies the line pressure to suit different operating conditions, For example, a higher pressure is required in the R position and when accelerating.

By-pass valve: protects the oil cooler from excessive pressure (a bleed off)

Relief valve: located immediately downstream from the oil pump, the relief valve opens if the line pressure becomes excessive

Secondary Regulator valve: Controls torque converter pressure.

Throttle Valve: Supplied with oil at line pressure and converts this into throttle pressure, which varies with the amount of throttle. This in turn actuates the shift valves in combination with the governor pressure.

Kickdown Valve: amplifies the throttle pressure by opening the kickdown circuit, allows shifting to take place at higher speeds than normal.

Governor modulator valve: Operates the cutback valve. In later models where the cutback valve has been replaced with a plug, supplies pressure directly to the cutback valve.

Cutback valve: This is supplied with governed pressure. The purpose of this valve is to reduce the throttle pressure, and, as a result, the line pressure at normal and high speeds. The advantages include a reduction in the power required to drive the oil pump and improved quality of gear shifting (read: it bleeds pressure off and softens the shift. possible point of modification)

Shift valve 1-2: controls the engagement of first and second gears, based on the throttle pressure acting on one end and governor pressure acting on the other. The center port supplies fluid to the planetary drive brakes which control 1st and second gears. The gear engages on the manner in which the throttle pressure and gov. pressure act on the valve.

Downshift valve, manual 2-1: When the gear selector is moved to '1' one end of downshift valve 2-1 is supplied with a modulated line pressure. Shift valve 1-2 is thereby moved to its bottom position, preventing an upshift. n the course of its travel, the downshift valve also opens a passage which admits line pressure to apply brake B3 (this affords engine braking in '1'). If on the other hand, the car is in 2nd when the selector is moved to '1' downshift will take place only when the modulated line pressure is higher than the governor pressure in shift valve 1-2.

Modulator valve, manual 2-1: operative only when gear selector is in '1', performs two functions: Reduces line pressure to brake B3, affording gentler engine braking, and operating in combination with downshift valve 2-1, it performs downshifting from 2nd to 1st with the selector in position 1, while also preventing downshifting at an excessively high speed.

Shift valve 2-3: The valve controls the engagement of 2nd and 3rd gears. Throttle pressure (which varies with the throttle opening) acts on one end of the valve and governor pressure acts on the other. A port in the center (sound familiar? similar to 1-2) supplies fluid to the planetary train brakes controlling 2nd and 3rd gears. The gear engaged depends on the manner in which the throttle pressure and governor pressure actuate the valve.

Downshift valve, manual 3-2: Line pressure is supplied to one end of the valve when position 2 is selected, moving shift valve 2-3 to its bottom position and preventing and upshift to 3rd. If the car is in 3rd when 2 is selected, downshift will take place regardless of the throttle opening or speed of the car.

Modulator valve, manual 3-2: The valve reduces the operating pressure to brake b1 for gentler engine braking in 2nd gear

Detent regulator valve: Located upstream of the kickdown valve, the detent regulator valve is supplied continuously with line pressure. In this position, it reduces the line pressure to a suitable circuit pressure which is then used by the kickdown valve to control the shift valves and downshift valve 4-3

Shift valve 3-4: Throttle pressure (which varies with throttle opening) is applied to one end of the valve and an opposing governor pressure (which varies with the speed of the car) to the other. Line pressure is supplied to clutch C0, and brake B0 through two ports in the middle of the valve, the position of the valve (or, in effect, the balance between the governor and throttle pressures) determining which is pressurized.

Downshift valve, manual 4-3: The valve is either operated manually by the switch on the gear selector lever or automatically by the kickdown function. Under these conditions the valve is supplied with system pressure or kickdown pressure, as appropriate, at one end. In manual operation (by means of the solenoid valve), the downshift valve moves shift valve 3-4 to its bottom position (i.e. 4th gear is disengaged). The downshift valve remains in this position until the solenoid valve is deenergized. In a kickdown shift, on the other hand, the valve is held in the bottom position only as long as the kickdown pressure is greater than the governor pressure. The latter acts in opposition to the kickdown pressure through shift valve 3-4.

Downshift D-2 control valve, manual: The valve controls the point at which 2nd gear is engaged when downshifting manually from position D to position 2, ensuring that this takes place in stages from 4th to 3rd to 2nd. Line pressure (throttled) acts on one end of the valve and the operating pressure for the clutch C0 on the other. A port in the middle of the valve controls the flow of fluid to downshift valve 3-2. The flow to downshift 3-2 is a function of the balance between the line pressure and clutch C0 operating pressure on the valve spool.

Control valve, rear clutch, reverse: Clutch C2 is provided with two piston surfaces. While the smaller surface is sufficient to enter reverse when 3rd gear is engaged, both must be used to prevent the clutch from slipping when in position 'R'. The function of the control valve is to ensure gentle engagement of reverse by the application of the rear clutch in stages.

Control valve, rear brake, reverse: The function of the valve is to ensure gentle engagement of reverse. This is achieved by application of brake B3 in stages. The brake is equipped with two hydraulic pistons, each with individual ports. Consisting essentially of a restriction in the supply to the pistons, the valve distributes the oil flow between the ports. Since the front piston receives a higher flow than the rear piston, it receives full operating pressure before the latter, prolonging the operation of B3.

Lock-up signal Valve: Line pressure is supplied to one end of the valve and governor pressure to the other. Two line pressure inlets are provided, one for selector positions 1-3 and one for selector position 4. when 4th gear is engaged and the governor pressure (i.e. speed of the car) increases, oil flows at line pressure from the control valve to the changeover valve.

lock-up changeover valve: The valve is actuated by oil at line pressure from the signal valve. Opening the valve reverses the fluid flow from the torque converter, operating the lock-up clutch plate and activating the lock-up function.

Accumulator pistons: each of the circuits serving the front clutch, rear clutch, and brake B2 incorporates an accumulator piston. The pistons are installed in parallel with the C1, C2 and B2 circuits. When supplying operating pressure to B2, for example, the fluid flow is divided between the brake piston and the accumulator piston. As a result, braking takes place gently when the brake is first applied and full opperating pressure is developed only when the accumulator piston is full. This ensures a smooth increase in operating pressure, resulting in gentler shifting.

Solenoid valve: Disengagement of 4th gear is controlled by the solenoid valve. Disengagement is performed manually using the switch on the gear selector lever. When the switch is operated, the solenoid valve (which is supplied with constant line pressure) relieves the pressure to downshift 4-3, moving the 3-4 to its bottom position and disengaging overdrive. The valve does not return to its idle position until another signal is received from the switch on the gear selector or the igntion is switched off.

Oil pressure switch, kickdown inhibitor (europe only): basically an oil pressure switch that turns on and off the overdrive soleniod.
 
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:cool: Watching closely... :cool:

I'm wondering how the governor works, how it can be modded for shifts. I like the idea of Toyota 2L-t box I have now, but it shifts too very early! The only gear I can rev the engine is 3rd or 4th.

Wondering what I can do the the shift valve springs... wondering if they need more/less tension to have it stay within gear longer.

Edit: Another option I am looking into is the 1g-gte twin-turbo Supra or a 2L-te Diesel turbo van transmission. (The 2L-T is not electronically controlled, it needs to be the electronic fuel injection diesel pump one, similar to the KZ engine. The newer 1KZ engines use a a340le instead.) These are also aw71, but with electronic control. This may put me into a better possition of controling shifts.
 
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for the governor inside of the tail shaft from what i have heard/seen if you want it to shift @ lower RPM you run a heavier setup, i posted some specs a while ago but i have 4 of them here with each one having a different weight. if you want it to shift higher you need to lighten it.

this means remove meat from the steel insert on one side and also the aluminum on the other side so that it is balanced

I would try to make more sense but I am to tired
 
:cool: Watching closely... :cool:

I'm wondering how the governor works, how it can be modded for shifts. I like the idea of Toyota 2L-t box I have now, but it shifts too very early! The only gear I can rev the engine is 3rd or 4th.

Wondering what I can do the the shift valve springs... wondering if they need more/less tension to have it stay within gear longer.

Edit: Another option I am looking into is the 1g-gte twin-turbo Supra or a 2L-te Diesel turbo van transmission. (The 2L-T is not electronically controlled, it needs to be the electronic fuel injection diesel pump one, similar to the KZ engine. The newer 1KZ engines use a a340le instead.) These are also aw71, but with electronic control. This may put me into a better possition of controling shifts.

1jz auto should be a a340le, same as what's found in a 960. the bellhousing isn't interchangeable (directly) between an a43/44 and the a340
 
Yes, the 1jz is a 30-40LE, but with a kick-down cable to control the pressure.

I'm looking at a trannie from a 1G-gte... 80's supra. These came with a aw71 style gearbox, but with electronic control.

But a 1Jz or 2Jz TT Trannie would be real nice behind a red-block, as these transmission cost about 100$ here in Thailand directly from the Japanese wreckers. (too lazy to mod the bell-housing, so I will stick to the aw71 style.)
 
Yes, the 1jz is a 30-40LE, but with a kick-down cable to control the pressure.

I'm looking at a trannie from a 1G-gte... 80's supra. These came with a aw71 style gearbox, but with electronic control.

But a 1Jz or 2Jz TT Trannie would be real nice behind a red-block, as these transmission cost about 100$ here in Thailand directly from the Japanese wreckers. (too lazy to mod the bell-housing, so I will stick to the aw71 style.)


interesting, whats the power rating on the 1g-gte? Sounds like it would have an a43DE or something similar, got any more info on this particular box?
 
Nop, no info at all, all I know is the trannie is rated 220hp standard from the factory. And people here put maybe ~350hp on a stock trannie with no problem. So I think it may be a good choice.

All I know is it has 3 solenoids, 2-shifts 1-lockup, line pressure is still controlled via throttle cable.
 
got this from a wiki, looking around a little more
A43DE

Four speed automatic with lockup torque converter and electronic controls

Applications:

* 1982-1987 Toyota Cressida
* 1983-1986 Celica Supra
* 1992-up Suzuki Sidekick (4L30E)
* 1992-1998 Volvo 960/S90 (AW 30-43LE)

that sound about right?

According to another one, the 1G-GTE was coupled with the A340E
 
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got this from a wiki, looking around a little more


that sound about right?

many, many other vehicles as well... my 1987 jeep has the AW30-40LE (2.80, 1.53, 1.00 & .75 ratios respectively) and the trans controller is a silly little box that only needs a tps input, brake switch and neutral switch to run the trans.. it also has a "power/comfort" thingy which is just a tripped lead on the TCM with extended shiftpoints. it has lockup torque converter and the 2wd jeep version should be identical to the 960 trans minus the bellhousing. if i ever tried to run a 30-40le i would use the jeep box to control it for ease of integration with megasquirt. the 30-40LE is very interchangable because the trans is almost always a 3 piece setup with bellhousing/trans/tailshaft housing... i have all the info needed to control the jeep version of it which i would assume is the simplist map of control compared to volvo/toyota control boxes as they are probably integrated with other modules

edit:// just looked it up, the jeep aw-4 (30-40LE) has a 450lb/ft torque rating from the factory :wtf:

more info at my jeep forums
http://www.jeepforum.com/forum/showthread.php?t=273048
of course written by the man with the turbo 4.0 i-6

awshifting.com also makes standalone stuff to control a340/aw4/aw30-40 setups for performance.
 
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Umm... the 7M of that era are coupled with the A340E, but all 1G-gte I see from the Jap wreckers are attached to a aw71 look-alike, but is electronic controlled.

These older ECT from Toyotas are very easy to use, it uses the TPS signal, water-temp, throttle cable, and its own speed-sensor.

Something I will look into in April when I have time. I will try to mate the Volvo engine to a 2JZ auto trannie, although it uses a line-pressure solenoid, but rumor says it has more clutch packs than a 1jz. We'll see.
(I got too many projects on hand... :-P My b21 busted on lastweek's track-day managed to drive the 300mile home though, no time and $ to drop the V12 engine yet, so a 230+ h-beam rods will go in mated to a M90, 7button clutch to drive around it for now. The amazon is getting a b230 standing straight + aw71, and the 144 is getting the 2.5L b230+16V :lol: Too many project, too little $ and time. Rightnow I'm job-less. I'm getting paid again in Feb. So things will be moving well after that. )
 
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Toyota previas have AW71LE (electrically controlled lockup) as well...

and I can vouch that the tranny in a 960 has its own speed sensor. I had to replace one once.

edited for clarification: not just the lockup in the AW71LE is electrically controlled, everything is...
 
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the 2JZ-GTE auto box is a a341E, and it has one more clutch and steel in the C2 (i think). The guts will swap into the older a340 case, so I'm wondering if the same will swap into the A43D/E/L etc. The valve body more than likely won;t but it'd be the guts that'd be nice to have.
 
an incomplete list of vehicles with transmissions from the same family:
Isuzu impulse 1987-1989 (turbo and NA) 03-72L / A45DL
Amigo 1992-1994 (03-72L /A44DL)
Isuzu pickup 88-95 (03-72)

Dodge:
D50 (also known as Ram 50)

MITSU:
87-90 Van/wagon – A44DL
87-89 Pickup (mighty max) A44D
87-94 Montero A44D/DL


Mazda:
99-up Miata A44Dl



Toyota:
Van (a44dl/a45dl)
Older cressidas (a44dl)
 
I know for a fact that the toyota previas had it too,

and i'm 90% sure that the toyota automatic 2wd pickups and 4runners with the 22re had it as well
 
4runners got a variant in the early years (89-91), and I think the previa is included in the "Vans". Like I said, its an incomplete list ;)
 
consider this: aw-71 does not have a removable bellhousing, 30-40/43LE does however, also consider that the toyota supra auto probably has the same aw bolt pattern to bellhousing as the 960 trans right? well here is where it gets interesting... the old aw-55 (borg warner bw55) used in old 240's does have a seperate bellhousing, a seperate bellhousing that shares the trans bolt pattern with an aw30-43 and the engine bolt pattern with a redblock... see pictures below. someone should unbolt an bw55 converter housing and see if it will bolt to a supra trans, or even 960 trans... then we might be getting somewhere in the usable junkyard parts department.




any thoughts? has the idea been discussed before?
 
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