i'm doing a maintanence blitz on the 940 that I just bought, and a few questions are cropping up here and there as I read through the wonderful FAQ section here. I'm doing the transmission flush this afternoon, but as I've never done this before there are two things that aren't clear to me:

1. the FAQ instructions say to "Drain all the oil from the transmission drain pan (2-3.5 qts depending on model)." I assume this is out of the drain plug in the bottom of the transmission oil pan, a 14mm bolt. But after I drain it, and before going on to the rest of the flush, do I replace the bolt, like in a normal oil change? The instructions leave this step out...seems like it could be important! I'm guessing the answer is yes.

2. Once I remove the cooler line from the top of the radiator, do I need to plug up the cooler line, or does it just sit there, open, while I do the flush ?

the last, general question, is whether it is a bad idea to do this job before installing a new radiator, which I will be doing when it arrives in the mail. Does putting new AT fluid through an old radiator contaminate it?

thanks in advance for any advice!

Good editorial catches:
1. Drain the pan and replace the bolt.
2. When you remove the cooler line from the radiator, you are removing the return line. You will install your vinyl hose on the radiator fitting, thereby intercepting all the fluid. The loose line just sits there.
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See the 700/900 FAQ at the drop-down menu above right.

You can flush the tranny anytime, preferably before the new radiator is installed so as to have clean fluid inside.
--
See the 700/900 FAQ at the drop-down menu above right.

great! thanks for the clarifications... I'm about to do it. I'll keep my fingers crossed that it makes for smoother shifting.

I've finished the transmission flush! I did encounter a little hitch that slowed things down though...when I removed the drain bolt on the transmission oil pan, it came out easily, but the threads were all screwed up. I wonder if this means that the previous person to install it stripped it? I've never stripped a bolt removing it, at least. IN any event, I had to borrow a tapping device from a friend and clean out the threads, and get another drain bolt. Thankfully that seemed to do the trick and there is no sign of leaking around the bolt.

As for changing the fluid, the procedure was as easy it sounded on the FAQ, but it appears that I slightly overfilled the transmission fluid. It is about a CM over the MAX mark? Will it damage the transmission to have a little excess fluid? And if so, does anybody know the volume of fluid between the min and max marks? I may have to make some kind of pump gizmo to remove the excess, as I absolutely don't want to mess with that drain plug again!

The transmission does shift smoother, no doubt, but it still has a little bump going from 1st to second, only if I'm pushing very lightly on the gas. I've never owned an automatic car before--is this considered normal? Or is this a sign that the transmission has some underlying issues that the fluid flush didnt totally fix?

I have an AW71 auto-trans 740T with that same characteristic.

It's now a lot better than when I first bought the car which wasn't exactly well maintained by the previous owner (despite the fresh looking ATF when I first got the car).

This what I did to smoothen the shifts out: Added Auto-RX to the trans fluid. Ran it about 2000km, flushed again. Added another dose of Auto-RX, ran it for 2000km, and then flushed again.

It's now a LOT smoother than when I first got the car.

Some people have good luck with using synthetic ATF to minimise this 'problem'.

lucast--and anybody else on here-- I had a quick question about your therapy for the rough shift between 1st and 2nd. are there any risks or downsides to using "Auto-RX"...I don't know anything about this product.

Also, did you first play with the throttle postion cable, or is that even something that would help make for a smoother light-throttle shift? The FAQ made it sound like this could help smooth things up. Does it make sense to play with that before adding any additives?

thanks

I did try to adjust the cable but to no avail.

Look there's always a risk adding any additive to your ATF but Auto-Rx has had a very good long history if you ask me. I have used it on four cars all to good effect. But check out their website and testimonials as well as the BITOG site for user reviews.

It's cleaned up and rejuvenated both the engine and the transmission on my 740T. The shifts are not silky smooth by any measure but heaps better than when I first got the car.

It did miracles to the engine of an 850 wagon with 200,000km on it that was badly serviced with plain dino most of its life - it's one of those mechanic tricks to use plain dino on a car that needs either full synthetic or a semi-syn (supposedly serviced by a 'reputable' Swedish car specialist workshop - blah). Truly freed up the power and even sealed off a small leak with the rear main seal.

I have used it with every old Volvo I have bought. Just make sure you use the prescribed quantity of Auto-Rx for the trans. It's a lot lesser than what you need for cleaning the engine.

A rather harsh light throttle 1-2 upshift is a common characteristic of "experienced" AW 70/71 automatics. The cure is a complicated procedure involving replacing some small parts in the valve body. Best to live with it as thousands of us are doing!
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Bob (son's 81-244GL B21F-M46, dtr's 94-940 B230FD, my 83-244DL B23F-M46, 89-745(LT1 V8), 98-S90, 77MGB and four old motorcycles)

I wouldn't even call it harsh...it just didn't register as the same compared to some of other (non volvo) automatics that I've driven, but as they weren't my cars I wasn't really paying too much attention. But knowing that it is standard on this model is more reassuring. I was mainly wondering if it was an indication that the transmission would be going soon. I can live with it just fine. IN fact, even a little more gas produces a very smooth shift--this after doing the flush.

The fluid is supposed to be measured while hot, so drive the car, measure the fluid again, and if it is overfilled stick a vinyl hose down the fill tube and siphon out just enough to max it out. Use one of those little vinyl pump jobs on the end of the hose: you squeeze it and it siphons. Or just drain a little by loosening the pan bolt.
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See the 700/900 FAQ at the drop-down menu above right.

i'll drain a little out because it is still a bit high when measured hot. but it occurred to me that another method to drain it, requiring only the tools used during the flush and a little less messy than the drain bolt bleeding, is simply to pop off the radiator line and reconnect up the vinyl tube used during the flush (my mechanic referred to the method as a "keith richards blood transfusion") and run the car for thirty seconds or so. I had zero leakage when I flushed the transmission, so this seems like an easy enough way to drain out a little fluid from the system without making a mess.

Dear ekphrasis,

May this find you well. Glad your tranny flush went well. Reminder: if you want to take free the ATF line at the radiator, be sure to hold absolutely still, the wrench on the radiator's hex fitting.

The Aisin-Warner (AW) transmissions are very durable, so long as the fluid is replaced periodically. I use Mobil 1 Synthetic ATF.

Most AW trannies outlast the cars, in which they serve.

The only sure tranny killer is failure of the in-radiator ATF cooler (or, in cold climates, heater). Water in the coolant dissolves the glue, that adheres the clutch pack facings.

The dissolved clutch material clogs the fluidways, some of which are very narrow. The transmission soon ceases to work.

Thus, if you see a pinkish film atop the coolant in the overflow tank, order a replacement radiator and enough ATF to do two flushes.

Hope this helps.

Yours faithfully,

Spook