I found a good AW71 Transmission with low miles, but my 940 has a AW71L Transmission.
Can the swap work OK?
What difference should I expect when driving?

Dear Volvito,

Good p.m. and may this find You well. The "L" denotes a locking torque convertor. Cars with turbo-equipped engines generally had the AW71 tranny installed; non-turbo cars generally came with the AW71L.

The lock-up feature improves mileage, as it cuts energy loss from engine to drive wheels. The difference you'll notice, is that as the car decelerates from, say 70 mph, you won't hear/feel the torque convertor unlock. It sounds/feels like a down-shift.

If I recall correctly, the turbo-equipped cars did not have the lock-up feature, because the power surge - when the turbo "kicked-in" - might be more than the tranny could take. Without the lock-up, the excess energy dissipates as heat.

The key difference between these trannies is in the control box, the rectangular box to which the tranny pan is attached. If you're adept at working with items, that have many small parts, I'd guess You could switch the control boxes - and torque convertors - and get the benefit of the low-mileage tranny body. I've never done this - my 940s have AW71L units.

Hope this helps.

Yours faithfully,

Spook

The reason you cite for not seeing the locking converter on turbo cars is false rumour. It is actually because the low N American speed limits cause the locked-converter engine speed to be too low for good highway performance. In markets where average highway limits are 120 km/h (75MPH) or higher, the L version IS fitted to turbo cars. Consider also that the older Toyota Supra, with nearly twice the HP of the B230FT, uses a locking converter on the same Warner transmission and it survives the power quite nicely.

Dear mapleleafer,

May this find You well. If speed limits shaped which tranny was supplied, then why were AW71L trannies put on cars with normally-aspirated engines, sold in North America? I'd guess that a car without a turbo is subject to the same speed limits, as one with a turbo.

I grant that a turbo-equipped car gets to 75 mph far faster, than does a car with a normally-aspirated engine.

But if low highway speeds in a country determined which car was sold there, then my 940s - normally-aspirated and built to North American market specs - should not have AW71L trannies. They certainly do.

I'm always interested to know more, so I always read with interest, your posts.

Yours faithfully,

Spook

It only has to do with the fact the turbo engines have lower compression ratio and feel anemic if the boost is low. The locked converter prevents good spoolup because engine speed is kept low. Once engaged (it is 100% speed dependent), converter locking remains unless a downshift is forced.

Higher road speeds in European counties will have engines running at closer to 3000 RPM versus our 22-2500. As I stated earlier... turbo cars in other markets DO get the locking converter with the turbo (including the 2.0 litre B200FT).

NA engines have no turbo needing spoolup and the light-duty AW-71L is the direct replacement for the discontinued AW-70L.

hello
so are you saying the 9 series turbo recieved the 03-70L in usa?
i am confused as i read different posts about this topic.
someone here posted (maybe Rhys not sure) the euro turbo cars got a lockup but had different valve body and TC.
i do not know and not sure how to find out for sure.
not saying i dont believe you, just so many different answers over the years.
thanks
Mike

I too found a lot of confusing and conflicting information, Because my interest was for rebuilding and modifying a couple of AW units... I put together all the information I could find to get the correct answers.

Here's the poop;

Back in the 1960s and '70s, Volvo used the British built Borg-Warner BW-35 3 speed automatic transmissions and so did Toyota. A modified version of that, replacing the two friction bands with multi-plate clutch packs, was introduced in 1974 and called the BW-55. Toyota contracted Aisin Heavy Industries to build the type 55 gearbox in Japan, and it was dubbed AW-55, later to be known as their A40.

Around 1979, Borg-Warner (US engineering) added an overdrive to the front of the AW/BW-55 transmission by request of Toyota for use in its luxury Corona model. It was produced by Aisin as the Toyota A42 and first installed in the 1981 Corona.

> In 1982, Volvo started using that OD equipped gearbox in 4 cylinder 240s and named it AW-70. Case marked "03-70"

> A beefier version had already been developed by then, with modifications at two thrust bearings, heavier one-way clutch, and more clutch plates in key location. It was called AW-71 (marked 03-71) and installed in the V-6 260 (1982) and the brand new 760 (1983). Toyota called this unit "A43". The AW-71L with locking torque converter was used in many European and Canada B230K.

> The third version in the Volvo lineup is the AW-72L used only on the 16 valve B234F engine. It is not a heavy-duty AW-71 as many think. It is mostly AW-71 geartrain (case is marked 03-71), with different planetary gearsets, giving lower ratios in first and overdrive, and a modified valve body (control box) to provide higher shift points to best use the torque curve of this engine. It makes a lousy replacement in a turbo car.

Applications;

AW-70; used only with B19, B200 & B230 naturally aspirated engines. Discontinued in 1992. When equipped with lockup, it is called AW-70L. 1983-87 non-turbo 740s may have been alternately equipped wit the ZF 4HP22 instead. It has almost identical gear ratios and locking converter.

AW-71; used behind all 2.8L V-6s (B28/B280) and all N. America B230FT (turbo). Some high-output non-turbo 4 cyl got the AW-71 or AW-71L (mostly Europe & Canada). Most European market turbo cars received AW-71L. 1993+ non-turbo 940s used a light-duty (low clutch plate count) version of the AW-71L in place of the previously used AW-70L.

Auto-transmission basics: The total friction area used for each function, along with the apply pressure used to cause each shift, is designed for the engine power expected. It is customized to the original application for proper shift quality and transmission life. Units of same model number (i.e. AW-71) between differing engine families (V6, turbo 4, non-turbo 4) are usually not good interchanges. Doing so will usually result in either: short clutch life, harsh shifts, wrong shift speeds.

AW-72L; used only behind 16 valve engine. Never offered without locking converter. So that nobody asks... it's the Toyota A45.

[Quote mapleleafer] AW-71; used behind all 2.8L V-6s (B28/B280) and all N. America B230FT (turbo). Some high-output non-turbo 4 cyl got the AW-71 or AW-71L (mostly Europe & Canada). Most European market turbo cars received AW-71L. 1993+ non-turbo 940s used a light-duty (low clutch plate count) version of the AW-71L in place of the previously used AW-70L.

Auto-transmission basics: The total friction area used for each function, along with the apply pressure used to cause each shift, is designed for the engine power expected. It is customized to the original application for proper shift quality and transmission life. Units of same model number (i.e. AW-71) between differing engine families (V6, turbo 4, non-turbo 4) are usually not good interchanges. Doing so will usually result in either: short clutch life, harsh shifts, wrong shift speeds. [Quote mapleleafer]

Thanks, that is some great information.
I have a question or two.

Do you mean that there are different versions of the AW-71L that were supplied in Volvo cars sold in North America? Some stronger....some weaker?
I have a 94 Model 940 non-turbo (B230F) sedan. with the AW-71L transmission.
If I ever have to replace my transmission do I need a AW-71L from the same exact model car?
Is mine considered the "weaker" version?
What model would have the "stronger" version, and will it work OK in my car?

thanks in advance for any response
steve

This is really a Toyota question, but until I read your post I didn't realize the extent of the Volvo/Toyota relationship. Here's my problem: I recently bought a 1985 Toyota Dolphin motorhome with a transmission problem, i.e. it won't go into reverse. As a matter of fact, it seams all gears are stuck in forward. With the possible exception of "Park", it wants to go forward in reverse, neutral, 1st, 2nd, and low. The engine is the Toyota 4 cylinder 22RE, and the tag on the transmission identifies it as an AISIN-WARNER Model 03-71, Serial #84MF 03848. I'm no mechanic, but I'm a willing student if the explanation can be dumbed down to "lay" terms. Thanks in advance for your anticipate reply.

It's almost always better to start your own thread rather than 'take a left' on another, it gets confusing for many.

My thought is that the shift linkage needs adjusting; have you tried a trans shop?

Hello
thanks for posting that info.
so it seems that the US spec turbo didnt come with any form of tranny w/lockup.
unless maybe a couple fell through the cracks like (Oh shit, just use that one over there sven)
i wish i could have a lockup tranny in my stock setup 95 944 turbo, it gets 25 mpg hyw, but more would be better.
i did put the AW72L in my 85 240 turbo and it didnt last long, maybe 4,000 miles. it allready had about 140,000 and i dont know its history but the timing belt broke on the car i got the tranny from.
i wouldnt mind the M90 but its a little pricey.
i wonder if the boost was turned down to about 5 psi how long a AW70/70 w/lockup would last. i have read where some folks state there US spec 7/9 turbo has the Lockup tranny, cant really call em a liar.
anyhoo good info
Mike

Yes, I was wondering why the specs I see in the web are reversed. AW71L for turbo cars and AW71 for non-turbo, when actually the non-tubo have the AW71L in North America.

Thank you so much. Good specs.
I will rather shop for the AW71L version. All my Volvos have the L version now so, it will not be good to have one different.

Is your 940 a non-turbo? The AW-71L fitted to the 93+ non-turbo is NOT the same gearbox marked AW-71 which was used on turbo cars since 1983. The non-turbo 71L is a direct replacement for the AW-70L used to 1992, and is lighter duty with different valve body than turbo use AW-71s.