BritishV8 Forum

General Category => Engine, Transmission, & Rear Axle assy. => Topic started by: 88v8 on January 11, 2025, 01:28:51 PM

Title: ATF Type F, G, Dexron
Post by: 88v8 on January 11, 2025, 01:28:51 PM
So the original spec for my Borg Warner 66 called for Type G fluid.
I also see recommendations for Type F.

I've been using Dexron III for years, perhaps wrongly.

I can't find any comparison between Type G and Dexron III.

Anyone any ideas please?
Title: Re: ATF Type F, G, Dexron
Post by: DiDueColpi on January 14, 2025, 02:05:23 PM
All the old BW boxes, 35, 65, 66. Use type "G" Or the old Ford Type "F"
The newer designation is "TQF" or "AQF".
Dexron should never be used. The clutch linings and seals were never designed to handle Dexron fluids.
However, if you are running Dexron now, do not change it back to the original type fluid.
The seals and clutches will have absorbed the Dexron and the trans is now addicted to it.
Changing fluid types now will most likely cause a failure.
If the "66" was rebuilt in the past it's very possible that Dexron compatible seals and frictions were used which would explain your good fortune.

Live like you mean it
Fred
Title: Re: ATF Type F, G, Dexron
Post by: 88v8 on January 15, 2025, 04:42:16 AM
Thankyou.
The box has been fed Dexron for 15 years, and has been rebuilt, so as you say I'd better stick with what I have.

From what I've read, Dexron gives a softer shift, so maybe no bad thing.
Title: Re: ATF Type F, G, Dexron
Post by: ag1234 on February 03, 2025, 05:58:16 PM
Way way back in AT class, a "trick" for GM automatics was to switch from GM fluid to type F for a firmer shift.
                                                                                   Onward,  Art.
Title: Re: ATF Type F, G, Dexron
Post by: MGBV8 on February 03, 2025, 08:19:44 PM
Did not know that, Art.  Then again, I am a 4, 5, or 6 speed guy.  I have only drag raced with manual transmissions.
Title: Re: ATF Type F, G, Dexron, Turbo 400 ?
Post by: ag1234 on February 04, 2025, 11:44:22 AM
I know, who cares/lol. Two items helped the GM T400 achieve such respect. 1. All upshifts RELEASE frictions to complete.
   2. Being a long main case, a center support bolt, near center of valve body, anchors the internals, (girdle).
                                                                                         2 cents,  Art.