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Which fluid for TH350?


Veteran Member
Lifetime Gold Member
Dec 9, 2009
Gordon from Jacksonville Fl
I have heard that the type F fluid is a little stickier, providing better band and clutch clamp up. Heard this in the late 70's early 80's, Type F was I believe specifically made for Ford trans (it had no friction modifiers in the formula), you could use F in GM trans but never use Dexron in Ford trans.


Veteran Member
Lifetime Gold Member
Nov 4, 2004
Ringgold, GA
Old hot rod myth from back in the day was to run type F because it made the transmission shift better. This was supposedly because type F friction modifiers would let the clutches grab quicker and harder. I tried it on one of my TH350 builds and didn't see any gains. I smoked that transmission build (and others) on happy gas. Finding a good builder cured that ill, and used Dex/Merc III. If your trans guy says he set it up to use type F, then use it. John Deere Hy-Gard seems to be the go to for a lot of drag racers, but TQ and transmission build is compensated for this fluid.


Veteran Member
Lifetime Gold Member
Feb 4, 2003
I think back in the '80s B&M kits said to use type F on rebuilds with their shift kits. The builder I used then told me to use that so I did. But it had to be a new build as you didn't/don't want to mix dex III & type F.

doug m

Veteran Member
Mar 31, 2020
STEP 28. Lower vehicle but keep the
rear wheels off the ground if possible.
Add 3 quarts of proper transmission
fluid, or B&M Trick Shift
to the transmission. While Trick Shift
is superior in heat capacity, lubrication
and friction material performance, if
Trick Shift is unavailable be sure to use
Ford Type F fluid. this is out of b&ms install guide for higher performance apps.


Veteran Member
Oct 9, 2020
And, if your brand of street auto trans has a lockup clutch --- and if trans is bucking in/out of lockup --- aka Shudder aka Judder --- common cause of that annoying condition is the Friction Modifier component within its fluid has worn out, packed up and left.
May seem counter-intuitive, but that Friction Modifier is in there to help the lockup To Slip; it's supposed to slip in & out of lockup --- should Not have a Hard transition (buck/shudder) between the two. And yes, the FM simply Does wear out. You can either replace all of the (perhaps pricey) fluid or renourish it with a dose of Friction Modifier concentrate --- a very good one that's widely available is 2oz tube of pn 19619 Instant Shudder Fixx; by Lubegard.

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