Changing from Dex III to Transynd

[reliefvalv]

Just curious in regards to compatibility and procedure for doing this. Have 03 Duramax and book calls for Dex VI. Have read that it hardens the gaskets? Transynd seems to be the rule of thumb. Do you change it all at one time (20 qts?) or drop pan twice 5K miles apart? Or is there another procedure? Thank you in advance!

[BFlinn181]

Use the search box at the top right of the page with the Google logo, you'll find lots of threads and posts on the topic. The usual practice is to plan two transmission fluid changes. So much is trapped in the torque converter, you won't get rid of all the Dextron on one change. A second change will reduce the Dextron left to a level most all can live with.

[70ChevelleSS]

You can use the search as suggested. You can also check the Allison Transmissions forum. Lot's of good info there.

[hzjcm8]

Originally Posted by reliefvalv

Just curious in regards to compatibility and procedure for doing this. Have 03 Duramax and book calls for Dex VI. Have read that it hardens the gaskets? Transynd seems to be the rule of thumb. Do you change it all at one time (20 qts?) or drop pan twice 5K miles apart? Or is there another procedure? Thank you in advance!

Use TranSynd. Drain the old fluid and change the spin on filter. Install TranSynd. Drive the truck for half an hour. Drain the fluid again and refill it and you're done. No need to change the pan filter. It's only done at overhaul.

[reliefvalv]

Thank you very much, still learning the ropes!

[reliefvalv]

I appreciate the feedback, thank you!

[Rocky Larson]

It may hold 20 but only 12 or 13 come out the pan each time. 7 gallons should be enough to do the two changes. YMMV as there are at least two depth pans available. Just didn't want you to go out and buy 10 gallons all at once. Start with 4 then see how it goes.Good Luck

[reliefvalv]

Thank you Sir!