300k on transmission fluid

2004LB7

Super Moderator
Staff member
Dec 15, 2010
8,678
3,137
113
Norcal
Transynd or Dex VI is recommended for a 2015 Alli, isnt it?
I remember Mike telling me he didn't like dex 6 and recommended Dex 3 over it for all 6 speeds. I think both from the viscosity and the seals hardening up from Dex 6

Citgo and Transynd where also on his recommend list from what I recall
 

DAVe3283

Heavy & Slow
Sep 3, 2009
3,792
397
83
Boise, ID, USA
I've been using Castrol Transmax DEX/MERC (which is a Dex 3 spec fluid). Use it in my main truck (790 HP / 1300 lb-ft at the tires) and my Suburban (425 HP / 750 lb-ft). That's what my builder said to use for the warranty and I saw no reason to stop once the warranty was up, though they said any Dex 3 spec fluid should work.
 

Bdsankey

Vendor
Vendor/Sponsor
Feb 1, 2018
4,840
1,891
113
Larsen, Wisconsin
OEM unit: Dex 3 or Dex 6 (based on year/OEM fill) or a TES-295 rated fluid (Transynd, AmsOil Torque Drive etc). I tend to see more pliable seals out of the 5spd units, I personally believe it has something to do with the Dex 6 fluid composition over time.

Built unit: Cheapest Dex 3 you can find locally, doesn't matter if it's a 5spd or a 6spd. If you want to spend money on a better fluid, simply make sure it's Dex 3 rated.