Guys, what is your favorite automatic transmission fluid? What do you like about it?

Me- I've just been using cheap, store-brand synthetic ATF in my TH350.
With foot-braking and a lower stall converter, my transmission temperatures usually don't get to 180 degrees, not unless maybe I'm double-entered.

I do plan to change things to get my trans temps warmer in an attempt to improve consistency.
Thank you much.

My transmission builder recommends using red fluid.... literally.

I have not had one single, internal component failure.

Clark

I have been using the Redline lightweight fluid because I believe that it changes less from cold to hot. I can say that I have seen no discernible change in et just from trans temps varying 140° to 190°. You won't get the life out of it that you do a more viscous fluid though.

I tend to be hard on my trans running two classes and sometimes running high gear only. Builds a lot of heat doing that. LOL

https://www.allisontransmissio...ds/on-highway-fluids

Castrol's variant is the most one we see used, but a 668 spec fluid is the best you can buy.

quote:

Originally posted by Brandon@BTE:
https://www.allisontransmissio...ds/on-highway-fluids

Castrol's variant is the most one we see used, but a 668 spec fluid is the best you can buy.

I switched to this a couple years ago based on prior conversations here on DRR. For many years prior, I used NAPA's house brand Type F fluid.

I can't say I noticed any difference between the two, but I'll trust that the TranSynd 668 holds up better when the conditions get extreme.

The beautiful thing about the Transynd is, the fluid will cool back down naturally when not being worked. Ive noticed for the last several years of using it, that the trans temps come down MUCH better coming back from a run than MOST other fluids do.

Nuz,
You dont have to run the fluid temp up to get a consistent transmission. If you switch to the Transynd, you will find your 1st pass will be much closer to the next runs. I have found the converter stall doesnt move anywhere near as much with temps with transynd, compared to other fluids.

quote:

Originally posted by 329L:
The beautiful thing about the Transynd is, the fluid will cool back down naturally when not being worked. Ive noticed for the last several years of using it, that the trans temps come down MUCH better coming back from a run than MOST other fluids do.

Nuz,
You dont have to run the fluid temp up to get a consistent transmission. If you switch to the Transynd, you will find your 1st pass will be much closer to the next runs. I have found the converter stall doesnt move anywhere near as much with temps with transynd, compared to other fluids.

I second that......one of the best things I ever changed....

Valvoline maxlife atf here

Castrol Transynd and never look back.

Unlike Dex 6 which I used prior, TES 295 and now newer 668 produces the same converter flash rpm at 125* or 180* in the TH400 I use with a 1+2 TB. My initial day warm up is starting the engine and leaving it idle until I have 130 – 140 * engine oil temp which is 8 - 10 minutes average. The rear wheels don’t turn and I don’t put it on the converter. I drive I to staging and after the first burnout trans temp is 125*. Presently there’s over 500 runs on the installed TES-295 fluid and I plan to go to 1000+ runs or trans rebuild prior to changing.

This LINK that Branden posted is for TES 668 and lists all the companies that manufacture this Exact formula under License from Allison. The App Num: 668-10xxxxx number is their license from Allison. I have Mobil Delvac 1 ATF 668 which is the exact same formula as the Castrol TranSynd 668 that is most referred to. I purchased it locally at Farm + Fleet. I wouldn’t hesitate to use any of the other suppliers listed in that TES-668 link. It's all the exact same.

valoline dexmerc i have no reason to not use it

Transynd. I run the Amsoil version. Meets the 668 and 295 specs. Everything else is second class!

Amsoil

Amsoil. Just sent my trans back to Select Performance after 425 trouble-free runs (7.20 dragster) just out of guilt... they said it looked great inside for so many runs.

Transynd here

Dex-merc usually Valvoline

not sure how great it is, but with dozens of praises on this site I just bought transynd for FED.

Only 17 post about the best ATF...Boy Oh Boy have times changed around here...

18 but only use orielys typeF in mine works fine consistant and cheap

I've used Lucas Semi-Synthetic AFT for several years and have no reason, or plans to change. Minimal wear, great consistency and doesn't cost an arm and a leg to buy.

Bob