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Basic 850 Flush vs Modified

volvo 850 flush

Whcich tyoe of transmission flush should you perform?

A Volvo will last as long as the engines they’re attached to. Proper care means a flush of the transmission fluid about every 30k miles. This is a very simple procedure and can be done for little more than the cost of the fluid.

MVS Forum Member dasapir asks:

A quick question regarding ATF flushing as described using the trans to radiator hose method. When flushing with ATF dexron III does it need to be the same high quality during the flushing as one finally adds to the end fill?

In other words, I plan on finishing with Mobil 1 synthetic so should I flush and spill 8 qts of Mobil 1 (I groan at such a waste) or can I use a less expensive (ie. lower quality/lower cost Castrol non-synthetic Dexron III) to do the flushing? My presumption is that near the end there will be some residual left in the transmission of the lower quality flushed ATF and therefore one should use the high price spead throughout. Or is almost all flushed out and therefore can one get away with the less expensive flush?

I would be much obliged if anyone could answer this simple querry.
thank you, thank you

MVS Forum Member MadeInJapan replied:

This is being discussed right now on Swedespeed.com. A guy there is saying that his mechanic flushes his transmission with low quality DexIII ATF before switching to the Volvo (expensive stuff) or Mobil-3309 (both are for later model Volvo’s- not yours) to save him money. I guess it doesn’t matter if a small amount of DexIII stays in his tranny so, to answer your question, it wouldn’t matter. Since our tranny’s hold almost 8 quarts I would go with 9 quarts of Mobil-1 ATF and the rest something else to make sure you get almost all of the old stuff out.

Come to think of it, that’s really not much of a savings…say you use 12 quarts total for the flush…3 is the $2.50 stuff….so you spend $7.50 total (plus tax), and 9 quarts of Mobil-1 which is around $6.00 around where I am…$54.00. Add these together and you’ve spent $61.50 plus tax, versus 12 quarts of Mobil-1 for a total cost of $72.00. You saved just over $10.00. I guess I will continue flushing with Mobil-1 and not using cheap stuff in my case…it’s about a $10 savings every 30K miles or so and I know that there’s actually more synthetic in my tranny (although the total amount may be very very small compared to the way you mention).

Speaking about flushing and trying to get out as much of the old as possible, this is what I would do. Drain the tranny pan by undoing the drain plug (make sure you get a new aluminum crush washer…I understand the same one we use for an oil change works fine). Measure the amount that came out. Fill the pan up with the same amount through the filler tube (dip stick tube). Most of your tranny fluid stays in the torque converter, radiator and the lines, so only about 3.5 quarts should come out. NOW, start your flush with Mobil-1. Run it until clear (well red, and not brown). You’ll probably still use 8 or 9, or maybe even 10 quarts of Mobil-1 ATF but more of the old stuff is sure out of there. Plus, since the drain plug is magnetic, you’ll have peace of mind by examining it for metal particals and also getting rid of the sludge on it.

Basic 850 Flush vs Modified

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