940 AW71L slips only in OD

Accumlator modded 71L behind a 16v turbo. Shifts great and quick between 1-3 but once it's in 4th and lockup any boost will cause the rpms to shoot up and if I keep in the throttle it'll slam into 3rd and off it'll go.

Time for a another transmission? I have a non lockup known good 71 in storage I can put in. How bad will the freeway rpms be with the 4.10 rear end? Throw some Lucas in it to see if it helps maybe?

Xeroni said:

Accumlator modded 71L behind a 16v turbo. Shifts great and quick between 1-3 but once it's in 4th and lockup any boost will cause the rpms to shoot up and if I keep in the throttle it'll slam into 3rd and off it'll go.

Time for a another transmission? I have a non lockup known good 71 in storage I can put in. How bad will the freeway rpms be with the 4.10 rear end? Throw some Lucas in it to see if it helps maybe?

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I may be wrong, but I believe that this is why the AW71L is not supposed to be used with the turbo cars at all let alone a 16V+T. I know at least with GM transmissions that boost + OD = burnt toast. If I'm romping on my stuff, I keep it kicked down. OD is for cruising, but I know that isn't exactly possible with a red block car. lol

I'm not even sure when the AW71L is supposed to lock up. I've never had one. Shouldn't it kick out if it's under a bunch of load? Also, can you tell if it's just the lock up that's slipping or is it the OD? If it's just the lock up and the fluid looks decent then you might be able to just throw in a converter and flush.

volvowagoon said:

I may be wrong, but I believe that this is why the AW71L is not supposed to be used with the turbo cars at all let alone a 16V+T. I know at least with GM transmissions that boost + OD = burnt toast.

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I have been running a accumulator modded AW71L as well and have not had any problems im aware of. If I recall correctly, the AW71/71L are a strengthened version of the AW70 because they were used in the 760/940 and some 740s/240s with turbocharged and higher-output NA engines. So a AW71L is meant for turbo power.

As for mine, 1st, 2nd and 3rd gear are all smooth and when I start to hit a higher RPM, out of habit, I just quickly and lightly take my foot off the gas for a second and press the gas back down. My AW71L sometimes seems to not shift into OD until I let off the gas for a second. I don't always do it and sometimes I do. I don't know if that means my OD is wacky or needs a new solenoid but I haven't ever had a problem. I'm a real casual driver anyway haha I drive like a grandma 90% of the time. Its a sleeper for sure but I mean, if you agree or not, the 740 is so damn comfortable when cruising at like 70, 75mph

volvowagoon said:

I may be wrong, but I believe that this is why the AW71L is not supposed to be used with the turbo cars at all let alone a 16V+T. I know at least with GM transmissions that boost + OD = burnt toast. If I'm romping on my stuff, I keep it kicked down. OD is for cruising, but I know that isn't exactly possible with a red block car. lol

I'm not even sure when the AW71L is supposed to lock up. I've never had one. Shouldn't it kick out if it's under a bunch of load? Also, can you tell if it's just the lock up that's slipping or is it the OD? If it's just the lock up and the fluid looks decent then you might be able to just throw in a converter and flush.

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They seem to want to lock up around 45mph. I've never had one that kicked out of lockup, engaging the kick down just puts it into 3rd. It feels more it's 4th that's slipping instead of the lockup but I'm not sure. I love the lower ratios with the L but going into 3rd to pass sucks because it revs the engine to 4k and that's just too much passing power lol.

Fluid is almost brand new, I just finished rebuilding the engine a few months ago. Guess it's time for another 71

Xeroni said:

Fluid is almost brand new, I just finished rebuilding the engine a few months ago. Guess it's time for another 71

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for you to read...

http://forums.turbobricks.com/showthread.php?t=68886

89_740Turbo said:

I have been running a accumulator modded AW71L as well and have not had any problems im aware of. If I recall correctly, the AW71/71L are a strengthened version of the AW70 because they were used in the 760/940 and some 740s/240s with turbocharged and higher-output NA engines. So a AW71L is meant for turbo power.

As for mine, 1st, 2nd and 3rd gear are all smooth and when I start to hit a higher RPM, out of habit, I just quickly and lightly take my foot off the gas for a second and press the gas back down. My AW71L sometimes seems to not shift into OD until I let off the gas for a second. I don't always do it and sometimes I do. I don't know if that means my OD is wacky or needs a new solenoid but I haven't ever had a problem.

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That's the way I had it explained by a seasoned Volvo mechanic.

As far as not shifting into OD, have you adjusted the kick-down cable and/or tried a fluid flush ?
I have an old AW70 and after some flushes with the most basic of synthetic fluid, it's manged to come back to at least 'collector' or 'rare' car status.

I don't remember where I read that, but if it holds then I might consider looking for an L! Having that lock-up for a couple extra mpg sure would be nice.

don't put the wood to it in OD, it'll smoke out really fast.

the good news is, they're not terribly difficult to rebuild...

Yeah it's my fault, I was being lazy and didn't fix the OD lockout button on the shifter. It's always shifted kinda lazily into OD since even before it was 16vt. I'll throw the 71 I have in it and see if I can rebuild the OD.