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My 940 wagon NA with the AW7XL (not sure but assume it is an AW70L) has me a bit stymied about its gas mileage. I have done zero troubleshooting as it is darned cold out here and I am lazy (suspect FPR and a lazy O2)...plus home improvement projects have consumed way too my of my time.
The first acts on getting the car was basic tune-up stuff including a tranny flush. The fluid was dark but not burnt and no signs of coolant contamination. It still shifts relatively hard and the shifts are too easily controlled by the gas pedal even at light throttle settings. I assume there is something going on with the kickdown cable but it does have sufficient slack.
Sooooo, after all that, I am not 100% sure how to tell if the lock-up is locking up as needed. When I am doing 50 on a dead level street I see about 200 rpm drop. Slightest whiff of a breeze or a .00002% incline and it pops back up 200 rpm. Most of the time I can only get it to "engage" with cruise on. Is this normal? Have not taken an extended highway trip with the car yet and not 100% sure what I should see given the 4.10 rear end that is geared so much lower than my 1990 240 DL with the AW70.
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My wife's 94 Model 940 has a AW71L with the Lockup Torque Converter.
I suppose that this type of transmission would be ideally suited for someone who lived on flat ground, but for me, who lives in hilly and mountainous terrain, they can be a pain in the a** sometimes.
The transmission almost never operates in 4th gear. When I'm going up a long hill or mountain road, the usual procedure is either manually lock it out of Overdrive or endure the transmission constantly shifting between 3rd and 5th gear (Lockup), and that's a big difference in engine RPMs.
The only way I can maintain 4th gear is if I start out and slowly accelerate thru the gears. Once it shifts into 4th gear, I can keep it there for a few seconds by holding the accelerator pedal at a certain place and maintaining
the constant...mild acceleraton. If I give it any more gas at all, it will shift back into 3rd gear, accelerate, shift into 4th for a split second and then the torque converter will lockup (5th gear).
It's great when I travel in the flatlands, and the fuel economy is really good as long as it stays in lockout.
I believe the transmission is performing as designed. It would have been better if there was someway to manually control the lockup feature.....sorta like another OD button, but that's too much to hope for I suppose.
ps....I really like the car.
steve
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You might have hit it there, with the kickdown cable adjustment thought.
Our 94 would have the 4th (no 5th) gear to go into lockup at about 45-47MPH under light throttle, with a 200-300RPM drop. It then needed to slow down quite a bit or be given a lot of throttle to unlock...almost enough throttle to simultaneously kick down into 3rd. If yours is unlocking at very slight throttle increases, I would say that's not the way it should go. The lockup function (engagement of the torque converter clutch) is governed only by internal hydraulic action in the trans - no electrical stuff going on.
You probably have an AW71L, and confirmation will be on the trans ID tag on the left side of the trans. It will show "03-71L". Ours had a harsh 1-2 upshift under light/medium throttle, and that seems to be characteristic of these at higher mileages. More info in the FAQ's.
Our 94 (sedan) would get ~30MPG (US) on the highway at a steady 65MPH. Along with the minor tuneup stuff you've done, get a fresh cam cover gasket and check valve clearances. Usually very stable, but will tighten up given enough operating hours. Alternatively, too-wide clearances can cause enough vibration to trigger ignition timing retard via the knock sensor. Volvo reduced the allowable valve clearance upper limit when the KS was introduced with the LH-II system in 1983, and emphasized this in the service manuals.
--
Bob: Son's XC70, daughter's 940, my 81 and 83 240's, 89 745 (V8) and S90. Also '77 MGB and some old motorcycles
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I don't think acceleration too different from the 240. Good acceleration at first and second and no complaints with third and OD for a 113HP engine. I can take most of the I77 mountains through Virginia and WV in third unless an 18 wheel cuts me off.
The 5th gear. Lockout occurs at 48 MPH at a mild acceleration. You can see the tach drop a few hundred RPM and because it is so subtle you cannot feel it but if your one with the car, grasshopper, you can feel the RPM drop. It seems like lockout drops out at about 45 MPH, decelerating with slight pressure on the throttle.
There is an 8 mile 45MPH hilly stretch of an 18 mile trip to work and I try my best to keep the car in lockout by speeding a little down hill and easing it up hill.
Improved MPG, sure, how much is the question. Keep in mind that in lockout there is no wasted energy, pushing fluid, inside the torque converter.
Hardly an accurate measurement but, newish tires, full tank of gas, night time, a half a pack of smokes with my sunglasses on, started a 325 mile trip during the remnants of hurricane Francis, 1998. It was a bad drive. All I could do is try to keep the car in lockout at 48 MPH while the speed limits were 55 to 65 MPH. Results, 31 MPH. Kidding with the smokes.
The only thing missing is an ecoT light during lockout but eco wasn't in vogue at the time. I'm sure Volvo missed a great marketing tool with lockout.
By all means, check the transmission label to make sure you have a lockout tranny or better watch the tach drop at 48MPH.
Tom
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"he 5th gear. Lockout occurs at 48 MPH at a mild acceleration."
Not sure what tranny you are talking about but the AW70L and AW71L have 3 gears plus OD plus the torque converter lock up. 4 gears if you will plus the lock up.
"By all means, check the transmission label to make sure you have a lockout tranny or better watch the tach drop at 48MPH."
It is dropping but it does not seem to stay in lock-up.
"I don't think acceleration too different from the 240."
The final drive gearing is significantly different (3.73? vs 4.10) than the 1990 DL Sedan with an AW70. The CD and weight are also different (CD is lower, weight is about 220#'s higher). All things considered, I have no idea what the RPM's at 65 in OD with lock-up engaged should be. It is not about acceleration...this is one of the quicker NA 7/940's I have driven.
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"Not sure what tranny you are talking about but the AW70L and AW71L have 3 gears plus OD plus the torque converter lock up. 4 gears if you will plus the lock up."
The AW70L, 71L, 72L, 4 speed or 4 gears with OD I will, and with lockout it has been very informally, referred to as the 5th gear, or like a 5th gear but of course not a gear as you said.
I remember comparing RPMs with my son, while on the cell, who has a turbo some time back. I don't remember the details and is probably groundless if he has a different rear end. I normally don't pay attention to the tach at higher speeds unless and I was beating carbon off the valves in a lower gear. I really must do this soon in my 244 town car. I'll check RPM at 65MPH in the 940.
Tom
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