Howdy all,
First time Poster, long time Volvo enthusiast. I recently purchased a 2000 S80 T6 in very good shape with only 92,xxx on the odo. To the best of my knowledge this transmission has never been serviced. The fluid is on the darker side, more of a brownish red but it does not smell burnt and the transmission shifts flawlessly. My question to you all, should I let it ride or should I go ahead and service it. Normally I would go ahead and flush but with these tranny's being made of glass I would like to know your experience and opinion

Thanks!

 

My two cents: flush no, drain/fill yes. For the cost of a case (12Q) of the appropriate ATF (check owners manual or google to confirm, but given its a GM tranny, its probably spec'd for Dex III) you can do about 3 drain/fills and be at close to 90% fresh fluid. as you drain the first shot, you have the option to drain through filter paper to check for any debris etc.

 

In my way of thinking mt6127 has brought to this conversation what 'flush' means.
So here is my spin on flushing.
To flush means to remove all the existing fluid and then circulate a fluid that is designed to clean the transmission parts, passage ways etc.
The 'flushing' fluid is then removed and new transmission oil is added. However this is not easily done therefore not practical. My Mercedes tech notes describe a way of draining most of the trans fluid, but it's a bit elaborate, maybe the Volvo workshop manual has a similar procedure.
I believe that's why, in part, mt6127 says no to flush and yes to drain and refill. I agree. If you remove only part of the fluid you leave some contaminated fluid in the transmission, you dilute the problem when adding the fresh oil, so doing the drain and refill several times, as mt says, reduces the total quantity of problems. I'm not going explain what those problems can be but its several different areas of science stuff.
The only thing I would add is, do the drain and flush several times as mt recommends, driving the car for a few 50 to 100 mile trips after each drain, get it good and warm. Then do the drain and refill a couple more times, the final one using the best fluid you can afford . Hopefully during the 3 or 4 drains/refills, prior to the last one the new fluid will do it's work to dislodge and suspend any problems.
Oh, did anyone say change the filter a couple of times.
And remember there are millions of cars driving around that have and will never have their transmission fluid, brake fluid, anti freeze, differential oil, clutch fluid, power steering fluid. Just saying.

As a side note: What I have done on brake systems. I use gas line anti-freeze to 'flush' brake lines.

 

Exactly why I made the differentiation. Volvo does have a flush procedure (at least for older models) which requires opening the transmission cooler lines to pump out the old and pump in the new. To me that just adds complexity and potential problems for what is an extra service item. I suspect that dealers have special tools to assist when they sell you a $400 flush special where you can do 90% with a drain fill for the cost of a case of ATF (still not cheap as you will probably need 12 quarts at $8-10 a quart for Dexron III... )