Transmission Flush not recommended for 850's

XxJenoxX · Post by **XxJenoxX** » 16 Apr 2010, 20:18

That's the first I've heard about the power flushing thing....although I'm sure it's valid.

The reason that I've always heard that you shouldn't do it is basically the same as why you wouldn't want to do an oil flush on a high mileage engine that hasn't been flushed......

Engines and transmissions get gunky buildup in them which can be loosened by flushes. This may sound like a good thing, but it's an incredibly bad thing when some of those gunky deposits don't flush out, and they basically move around and clog things up even worse than they were just being left alone in there.

Post by **JRL** » 16 Apr 2010, 20:31

polskamafia mjl wrote:Well...I don't believe there is any harm in switching to synthetic. I think it is an old wives tale...lol

You are very wrong and it's NOT a wives tale

Joe Hurless · Post by **Joe Hurless** » 16 Apr 2010, 21:39

Drain/fill every 30k until the car takes it's last breathe.

Craigd2599 · Post by **Craigd2599** » 17 Apr 2010, 04:14

Not an old wives tale. Using synthetic in a high mileage trans that hasn't been serviced will usually deteriorate the seals and clutches

XxJenoxX · Post by **XxJenoxX** » 17 Apr 2010, 08:17

Yeah, there's definitely no harm is draining in filling....unless something is REALLY wrong, but the flushing, I would leave out.

Mine has 211k, and it really appreciated the drain and fill. Probably in for another, since I'll have to do the other axle soon enough.

volvomileage · Post by **volvomileage** » 17 Apr 2010, 10:09

having no clear idea about the tranny maintenance (but the previous tranny fluid wasnt smelling burnt)
i did an flush and fill with the new castrol dex vi (semi syth and backward compatible ) over a year ago and have no problems watsoever, smooth shfts and no leaks..

it all depends how far seals and tranny are gone, but one thing for shure no machine flushes for my car drain and fill works great, its a bit of work but what the heck

claymore850 · Post by **claymore850** » 17 Apr 2010, 22:26

I feel that power flush will remove all the gum inside, maybe breaks the filter...remember..sometimes the rust became weld..

I just recomend the drain and fill flush..no external machines... for my 850 it has been worked ok since '94..

trtvolvo · Post by **trtvolvo** » 17 Apr 2010, 22:37

NO flush. Soon after dealer shop flushed mine (at 95K miles), transmission failed and had to be replaced...

Post by **Hoov** » 17 Apr 2010, 23:58

I did the forum recomended "drain & flush" (Not a power flush) Maybe should be called "drain & replace" ... Whatever.
Point is my trans w/164,000 thousand miles was working flawlessly but the fluid was black & smelled burnt.
I decided to go w/cheapy Valvoline Dex III-mercon ... Well, truth is Kragen had a "Managers sale" & I got the stuff for $1.76 cents a quart! ... Sorry, could NOT pass that up so did the modified drain & fill.
Ya Know? I was very happy with my trans performance before I did this but just didn't like the fact that the fluid smelled bad & that Volvo said, "Good for life" & "Just top off" ... Horse crap!!! That simply is not logical. Fact is, common sense would tell you it's just wrong.
Soooo, I followed the recomendations on this forum. ... LAWD! ... I know how this is about to sound but it is a fact. You now have to actually pay attention to realize the trans has shifted. I'm talking about just puttering around town. I have a GLT not a turbo. When putting her into "sport" there is no "Shift", she just synchcronisly (is that a word?) moves & "Moves" is the right word, to the next gear. No pause, no hystrionics,just does it & the tach drops with little clue from the engine noise. Truly wonderful! (Which says something about Volvo engineering).
From now on ... Every thirty thousand miles ... Drain & replace!!! ... Flush at the shop? ... Don't count on it!

XxJenoxX · Post by **XxJenoxX** » 18 Apr 2010, 08:07

As far as I know, drain & flush is NOT the same as drain & fill.

Flushing implies that you are washing something through the system to clean it out, where drain and fill is just removing & replacing. With the latter, you're not disrupting any of your internals. Depending on what you're doing to your car, a drain and replace may even be necessary, or easier than the alternative. Had to be done for my axle, short of making a damn mess.

And just the phrase 'transmission power flush' makes me shiver, especially on high-mileage transmissions. IMHO, the benefits simply DO NOT outweigh the risks.

Transmission Flush not recommended for 850's

Re: Transmission Flush not recommended for 850's