Transmission Fluid

[brujo_bob]

Good morning. I’m wondering what kind of transmission fluid does a 1966 Chrysler 300 take. It’s a 383 engine with a 727 transmission. TIA.

 

[CBODY67]

When the car was produced, the spec was Type A, Suffix A atf. Of course, Chrysler/Mopar Parts had their own part number for it.

When GM introduced their first DEXRON atf in 1968 or so, Chrysler went with that spec for the TF automatics. At this point in time, there have been many evolutions of the Dexron family of atf, each on addressing some issue that arose. The current Dexron VI atf is a semi-syn or full-syn atf which GM claims is completely backward compatible to their 1949/first automatic transmission, but is also fully-modern in all respects. The Dexron III atf is still around, in "Multi-Make" atf which mentions GM vehicles on the back of the bottle, specifically. Or as ACDelco Type III atf.

Back then, many "hot rodders" used the Ford-spec Type F atf in their automatics. It had a bit more initial grab than the Dexron atf did, for a bit firmer shift feel. Not unlike the B&M Transmission "Trick Shift" atf, which was blue. Ford ceased licensing the Type F atf in about 1986, when they shifted to their Mercon atf, which the aftermarket combined to become "Dexron/Mercon" branded fluid.

I will admit that I have not investigated the various Mopar ATF+ fluids and what makes each one unique compared to other atf. I do know that the fwd automatics first spec'd Dexron + a particular LubeGuard additive, but that later started with the ATF+ versions.

So, for "plenty good enough", the basic Dexron III atf (or later equivalents) will do fine. If longer life is desired, then the later Dexron VI or latest ATF+ fluids can be better, but at a higher price due to their "syn" components.

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CBODY67

 

[detmatt]

Topping off or flush and fill?
Per my transmission guy I use ATF+4.

 

[brujo_bob]

Topping off or flush and fill?
Per my transmission guy I use ATF+4.

Flush and fill

 

[brujo_bob]

When the car was produced, the spec was Type A, Suffix A atf. Of course, Chrysler/Mopar Parts had their own part number for it.

When GM introduced their first DEXRON atf in 1968 or so, Chrysler went with that spec for the TF automatics. At this point in time, there have been many evolutions of the Dexron family of atf, each on addressing some issue that arose. The current Dexron VI atf is a semi-syn or full-syn atf which GM claims is completely backward compatible to their 1949/first automatic transmission, but is also fully-modern in all respects. The Dexron III atf is still around, in "Multi-Make" atf which mentions GM vehicles on the back of the bottle, specifically. Or as ACDelco Type III atf.

Back then, many "hot rodders" used the Ford-spec Type F atf in their automatics. It had a bit more initial grab than the Dexron atf did, for a bit firmer shift feel. Not unlike the B&M Transmission "Trick Shift" atf, which was blue. Ford ceased licensing the Type F atf in about 1986, when they shifted to their Mercon atf, which the aftermarket combined to become "Dexron/Mercon" branded fluid.

I will admit that I have not investigated the various Mopar ATF+ fluids and what makes each one unique compared to other atf. I do know that the fwd automatics first spec'd Dexron + a particular LubeGuard additive, but that later started with the ATF+ versions.

So, for "plenty good enough", the basic Dexron III atf (or later equivalents) will do fine. If longer life is desired, then the later Dexron VI or latest ATF+ fluids can be better, but at a higher price due to their "syn" components.

Check the "Search" function for other threads on this subject.

CBODY67

Thank you!

 

[MONC440]

Flush and fill

If you have a drain plug on the TC drain that also, if not don't worry about it. If you can find out what the previous owner used that would be best because I never like to mix fluids and you can never get all the fluid out unless it is a rebuild (or use a flush machine). When I do rebuilds on 727 and 904 I suggest using Dex III on a daily driver and Type F (or some kind of racing ATF) for performance but I also build the trans for what it will be used for. On a daily driver you want a little slip in the fluid because the clutches and bands don't engage as fast as a trans built for performance. Performance transmissions have less overlap of shifts so you want a fluid that bites and doesn't slip, it is a little harder on driveline components and the trans is not expected to last 100K miles before the next rebuild. Just my $0.02

 

[413]

DEXRON/mercon

Don't need type f or atf+4