synthetic trans fluid vs regular trans fluid

michael schulte · Post by **michael schulte** » 10 Jan 2011, 11:18

I have a 97 850R wagon with 160,000 mi. My fluid was changed 50,000 miles ago with dextron III. Every thing is fine transmission wise. Just was wondering if going synthetic was "a good idea" or not. Also is using a machine to flush the trans fluid, better than using the old method flush, a 'good idea".

Post by **cn90** » 10 Jan 2011, 12:30

Regular Dexron-III is fine.
However, I use Mobil1 Synthetic ATF fluid, the shift is smoother when cold. Otherwise, difficult to tell the difference between standard vs synthetic ATF.

Re ATF Flush, no need to use any machine,. just disconnect UPPER cooler line and flush.
It has been discussed here 100 times.
When replacing the Upper Cooler line, watch the clip, it only fits one way, do NOT reverse the clip.
Also add a screw-type clamp over the clip to prevent the clip from coming apart (happened to me!!!).
Add another clamp on the LOWER hose clip too.
Search forum for pics and DIY.

Post by **polskamafia mjl** » 10 Jan 2011, 13:05

+1 But I have heard that the synthetic fluid also holds up really well (better than Dex III) when it is really hot out.

Post by **JDS60R** » 10 Jan 2011, 14:35

Avoid the flush machines.

A quality synth does a great job and does hold up. I prefer Amsoil ATF.

Post by **boosted5cyl** » 10 Jan 2011, 15:20

Ive had good results with Supertech Dexron VI from Walmart in both the V70 T5 (203K miles) and the S80 T6 (189K miles). It's less than half the price of other Dexron VIs but still has to meet the spec. As for synth vs "conventional", theres some debate as to what oils and fluids are actually synth not tom ention what synth actually means or requires. Get a Dexron VI, do some drain and fills. Call it good.