Hi all,
I have a 1994 940 wagon that I was told by my mechanic should have a transmission flush. The car has about 69K miles and I bought it with about 63K miles, so I am the second owner. I don't what sort of tranny service the car got prior to my owning it.

I recently had the fluid drained and refilled, but my mechanic said that this is not good enough. He does a service where he hooks a machine up to the cooler lines and does the "flush".

I called another transmission service place and they said that they don't do flushes and they don't recommend it. They said something about it damaging the clutch. They do a "service" where they drain and refill the fluids and clean out the pan and change filters.

So basically I am a little confused by the conflicting information. What do you recommend I do??

Many thanks!

Not that this is a huge issue, but when I did this a couple months back I could in no way get the fluid in as fast as it was coming out. I ended up stopping the car four times to allow the fill rate to catch up. All-in-all not too messy. about the same as if you change your own oil.

I spent about $38.00 on the valvoline synthetic ATF. Mobil One is a lot more expensive.

Incidently, if you are flushing your Tranny, you ought to get your power steering fluid taken care of at the same time. It's a bit messier and requires a suction tool of some sort (I used a new turkey baster). The system fluid is the same, so it makes sense to tackle both task at about the same time - you save on the bulk fluid purchase :)

I recommend installing some Magnafine filters in each system after the flush (you can get the 5/16" and 3/8" filters from Pat Hannon for $20.00 each on eBay and he includes good instructions). People seem to agree that these are great additions to both systems and will catch loose metal particles that might be circulating in the systems - although the tranny is less likely to have metal bits in it.

Like everyone says, don't bother dropping your pan. You risk bending/tearing the dipstick attachment tube and that's just plain tragic.


--
You mean Volvo makes cars that are *NOT* Wagons?!?

Do the flush... it couldn't be any easier.

I've done the flush on two bricks with great success. But on the third, I encountered something new:

- Ran the usual 12 quarts through, and it was still pumping out dirty fluid.
- Ran another 4 quarts through (16 total) and it seemed fine.
- Re-checked the fluid level several days later, and realized I had over-filled by about three-quarters of a quart. No big deal, so I commence to let the tranny "pump out" the excess fluid through the return line (just like you would with a complete flush). To my surprise, the three-quarters of a quart that I removed looked almost as bad as the original stuff.

My conclusion: that there was a heavy film of sentiment in the pan that was picked up by the fresh fluid. I think I should have dropped the pan for a good cleaning on this car. The car is a '93 945 N/A w/ 130K miles.

I can tell you, when I pulled the pan on my Mercedes with 130K miles I was shocked to find a 1/8" film of metallic, greasy gunk lining the whole bottom of the pan. It wiped right out with a rag, but it's stunning to find that much crap in a system that's supposed to be kept very clean.


Jeff Pierce
--
'93 945 Turbo ( one kickass family car ! ) 197K miles, '92 Mercedes 190E (my daily driver) 170K miles, '85 Jeep CJ-7 w/ Fisher plow 225K miles, ’95 Lawn Chief

I agree w/spook. However, mechanic #1's machine is designed for the flush. If you don't want to get your hands dirty, go for it (I assume he is charging you about $100? that seems to be the going rate around here). Do it yourself for the cost of the fluid and some hose and take the family out to dinner. Or, have your guy do it so he can take his family out to dinner. Your call, but avoid the drain only.

Bob K

'94 945T (daughter co-opted it for college, used to be mine)
'99 S80 (mom-in-law's)
'88 240DL (son's)
'84 242Ti (for sale)
'89 560SL (wifemobile)
'88 300TE (my commuter)
'68 GT500KR (future commuter/under restoration)

I agree with Spook as well, however I never made the move to synthetic. It just seems too expensive. I flush my system out myself, using the upper transmission cooler connection on the radiator, and use Mobil ATF from Costco. I get an entire case for about $13.00. Usually use about 9-10 quarts to make sure I get it all out.

I do it every 20k like clockwork. Takes me longer to clean-up when I am done....THAN to perform the actual maintenance.

I have 263k miles on my AW-71. Shifts are smooth and easy.

Question for Synthetic Users....is it worth extra cost? How often do you flush synthetic?

Synthetic will easily last 4 times as long under heat so I believe it is cost effective. Just reduce your change intervals to get equal cost per mile and you will still have a better life.
--
'96 965, 16' wheels, rear 18mm bar & Koni + 204HP cams at 125K. Had '85 745 Turbo Diesel for 200K.

I agree with Spook. I own 2 1995 940s and the flush procedure takes me less than 30 minutes. It improves smooth shifting and definitely will extend the life of the tranny. BTW, the "filter" is really a strainer for big chunks. A tech service bulletin issued by Volvo recommended no longer removing the pan because it was time consuming and changing the screen was not necessary. Also, there is a rather wierd looking connection/fitting on the side of the pan for the dip stick tube, and it is easy to mess up the flared fitting on the tube if it is disassembled, dont ask how I found that out.

anyhow, flush it using the FAQ procedure and you will be glad you did.

good luck

sorry about the double reply ... didn't mean it ...
well as i was saying , i will be skeptic of any other brand of trannys when it cames to flushing , but after getting the chance to work with this AW's , i will srongly recomend a full flush as per faq... this trannys are bullet proof...


just my opinion
coper

I agrre with spook ...

I agrre with spook ...

Draining only gets less than half of the old stuff out. Follow Spooks instructions, it's easy, If you hook a piece of loose hose to the fitting comming oit of the radiator and run it over the fender to the waiting jug, you don't even need to jack the car up
--
-------Robert, '93 940t, '90 240 wagon, '84 240 diesel (she's sick) , '80 245 diesel, '86 740 GLE turbo diesel, '82 Mercedes 300SD for sale

I'm with mechanic #2, I'd just drain.

Why? Unless the transmission has been contaminated with antifreeze, I wouldn't worry about mixing some old fluid with the new. The screen will filter out the solids. Trans fluid is not engine oil and of course isn't subject to the same levels of contamination (gas/water).

This is my opinion.
--
Norm Cook Vancouver BC; 1989 745T 204,000KM

Norm, the usual failure mode for tranny fluid is two-fold: overload with clutch facing and wear particles, and oxidation and viscosity breakdown from high temperatures. Over time, both will contaminate the fluid and it begins to appear both brownish in color and with darker wear particles in suspension. A simple pan drain ensures that about 1/4 of the system fluid is replaced at a time. A flush, on the other hand, replaces all fluid and removes most contaminants. I used to agree with you, but my experience on eight cars (both GM and Volvo) is that the flush is a good idea, especially if followed by synthetic ATF which is not subject to oxidation and viscosity breakdown. It has demonstrable effects on shift quality, tranny lifetime, and fluid appearance.

OK I learned something, I didn't realize so little fluid was extracted via a drain. But I am still not convinced.

I did a search and there are some for/against. And so you know my search wasn't skewed with "transmission flushes are big waste of time" here it is: Google Search: transmission flushing good idea

I guess I consider it akin to changing out power steering fluid; IE remove a bit at a time and gradually it will become clean.

Instead of flushing I'd just do an earlier drain.

BTW, is the flush done with respect to normal fluid flow of the trans? I would not want to have fluid flowing backwards as valves etc were not engineered for that use.
--
Norm Cook; Vancouver BC; 1989 745T 206,000KM

BTW, is the flush done with respect to normal fluid flow of the trans? I would not want to have fluid flowing backwards as valves etc were not engineered for that use.

Norm,

Yes, flushing at the return port scavanges the old fluid that would normally go back to the tranny. The flow direction is normal.

I much prefer this method over repeated dilutions of old fluid with new (or visa versa) over time.

As for the so-called "filter", it's just a screen that never caught anything that I could see, back when I used to drop the pan. I don't do that anymore, as I agree with this Volvo TSB:

=============>
posted by Gregg Shadduck on Thu Feb 10 08:06 EST 2005

From the clumsy but economical "Popular Science" [who?!] CD collection of TSBs (technical service bulletins) from Volvo:

TSB 17106
Dec 1990

"ATF filter cleaning deleted"

for 200/700/900
for all those AW 70/70l/71/72L transmissions
and for ZFHP22
(Does NOT apply to BW*)

"It is NO LONGER REQUIRED [capitalized in original] to clean and inspect the Automatic Transmission Filter..." [The tiny filter screen, which you get at, of course, only with SUBSTANTIAL effort.]

Advised to still replace the ATF fluid at specified intervals, and to flush the transmission cooling system.
<==============

--
Bruce Young
'93 940-NA (current) — 240s (one V8) — 140s — 122s — since '63.

Dear elbee,

Good p.m. and may this find you well. Congrats on finding a 94 940, with such low miles!! I bought one, with 70K (now 75+K).

Here's what I recommend. Flushing the tranny is a good thing. Flushing the tranny, and replacing the fluid with Mobil1 Synthetic ATF, is an even better thing.

You can do this yourself. See the FAQs, under FEATURES, above. You will need:
(a) several one-gallon, screw-top milk jugs (empty, washed, and allowed to dry)
(b) 12 Quarts of new ATF
(c) A few feet of clear plastic tubing and hose clips
(d) 2-10" adjustable wrenches (loosen the upper trans line connector to the radiator).

Draining the transmission pan removes 1.5-2 Quarts of the 9 Quarts of fluid, in the system. Flushing removes all of the old fluid.

It is not normally needful to remove the pan/clean the filter.

Hope this helps.

Yours faithfully,

spook

I know, the thought of all that dirty oil sloshing around is just too much for some of us.
Volvo though, recommend either very long or no! oil change intervals.
Putting synthetic oil in has made a modest improvement to the already very smooth 960 transmission.
I did it the drain way, by starting the car (in Park!) with the drain plug removed, I was able to drain 4 qts (half of oil capacity). Without starting the car, 3 qts.
Perhaps the most interesting benefit of synthetic oil is its lower coefficient of friction in comparison to regular oil. Transmissions run cooler because of lower frictional losses.
Amsoil claims fuel economy increases of approx. 5% with cars running in synthetic oil.

Good luck,

Dan