DOT3 or DOT4 ATF

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DOT3 or DOT4 ATF

Postby bgilbert » Sun Mar 16, 2008 1:07 pm

Got my tranny draining at the moment, gonna add an 03 pan which has more capacity. I remember reading a discussion on types of ATF. How DOT3 and or DOT4 worked in our 727 or in my case the 518. How it affected the shifts, firm, soft etc. Well my Autozone doesn't even carry DOT3 ATF, haven't checked around anywhere else yet. Can one even get straight DOT3 or do you have to get the 4 which says 'meets or excedes' blah blah dot3 etc? I know Philip had something to say about this at one of our SOP's, but I can't quite remember it all. What do you guys suggest?
Bill Gilbert
85 D350 crew with 90 6BT intercooled Getrag 3.07's
93 D350 single cab Getrag 3.54's.
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Postby PToombs » Sun Mar 16, 2008 1:14 pm

Do you mean ATF +3 and +4?

Drink less, pay attention more! :study:
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Postby Philip » Mon Mar 17, 2008 8:40 am

The fluids will interchange.

The ATF4 just has some different additives.

The MFG's and the oil industry have to keep the fluids where they can interchange with the wide range of year models of transmissions on the road today. Out west there are still cars on the road that use ATF 1&2 which you can't even find anymore.

The higher number ATF fluids seem to be just a little thinner from the previous number. This will change the way a trans shifts. Most of the time the shifts will be a little firmer and faster.

You can even use Ford ATF in a Dodge trans. It is a ligher fluid and the shifts will be faster. The stall range will go up just a little on the converter. On a lightly built gasser the stall normally goes up around 150 RPM or so with the Ford fluid. If your running in a limited class on a drag strip. That extra 150 RPM helps on the launch. :D
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Postby bgilbert » Mon Mar 17, 2008 12:34 pm

Sounds like atf+4 will work fine then. I know Matt just changed his with +4 and he likes it. What about line pressure? I know how to adjust the bands, but not sure about LP.

Plus where in the heck does one find anything 'weld-in'? Locally I'm batting zero. Looking for a weld in bung for the tranny pan.
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Postby PToombs » Mon Mar 17, 2008 2:49 pm

Gotta hardware store? Go buy a pipe coupler, weld it in. Oh, wait, I said "buy"! :shock:
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Postby bgilbert » Mon Mar 17, 2008 3:46 pm

PToombs wrote:Gotta hardware store? Go buy a pipe coupler, weld it in. Oh, wait, I said "buy"! :shock:

Yeah I seen those, they're ugly. I want something sweeter looking like a flat flange real deal weld in bung. But looks like if I want it in the pan, I'll have to go that route of 1/8th pipe couple.

Or do the sensor in the cooler line. How did SamsRam's/MadMax do it? Remove the OD kickout switch, thread in a T coupler, install switch AND temp sensor? What threads? Hmm, $35 a year to be able to do a search, nah :D .
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Postby PToombs » Mon Mar 17, 2008 4:51 pm

Pull the switch, twist the wires together, install sender. ;)
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Postby Philip » Mon Mar 17, 2008 4:55 pm

Bill the pressure adjustment is the allen head screw on the driver side of the valve body about 1/2" of so behind the shift shift linkage. Turn it about 1/4" turn clockwise. No more than that and you can cause expensive problems.

Bill do a search for transmission drain plug kits on google. You will get a lot of hits on that. Most kits are not the weld in type.

Or just hit a junkyard and find an old 727 pan and take the drain setup out of it.

Bill that sender in the front cooler line is a temp sensor. If you take it out throw a 1k resister across the terminals. If you don't the trans most likely will not go into OD. The PCM has to see a temp reading to allow upshift to OD.
93 W350 Club/cab w/duals, buckets & console, B&W flatbed, G56, 6 spd, 3:07 rears, gages, HX40/16, 4" exhaust, 6X.018 sticks, rear air ride suspension
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7176E

Postby Ace » Thu Mar 20, 2008 3:27 pm

The only difference between the current + Mopar trans fluids is the base stock. +3 uses a conventional GpII base, and +4 is a semi-syn GpIII base. They have the same add packs, blended to meet the Chrysler 7176E spec. They are basically interchangeable, +4 just lasts longer and runs cooler. Despite being alot cheaper in recent years, +3 is not available anywhere I've been in the past year or so, so it's really a moot point.

You can run +3, +4, DexIII, the new DexIV, or even TypeF in the older 727-based autos. They wil all work fine, not hurt anything, just behave a little differently. You'll get smoother shifts but more heat with the + fluids. Dexron III was the original factory fill. DexVI would be the technically correct best substitute, but cost the most. It'll shift crisply and being a GpIII based oil, last long and run cool. Run TypeF if you want the firmest possible shift and change it more frequently.
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