Trying to find what transmission is in my 1972 Dodge Polara?

[72polarbear]

Accidentally, unscrewed the back up light switch and a bunch of fluid came out. It looks to be time to change it anyway so I need help to identify what trans and what fluid it needs. The transmission may not be original. I can upload more photos of needed I’m just not sure why exactly is needed.

 

[CBODY67]

Match the shape of the oil pan to the illustrations in the aftermarket catalogs for such Might be some illustrations of such at www.rockauto.com, too?

On the 727s, seems like there used to be a casting on the lh side of the bellhousing area which had "727" on it? Not sure if the 904-family would be similar?

CBODY67

 

[Davea Lux]

With the 318 engine, you are most likely going to have the 904 series transmission. You can use the modern ATF 4 in this transmission and the 727 series. Be sure to drain the torque convertor, replace the filter and do a band adjustment when you service the transmission. The torque convertor drain can be accessed via the small removable plate on the sheet metal cover on the lower part of the bell housing. If the transmission has been rebuilt at some point a torque convertor without a drain may have been installed. Service procedure is in the FSM which can be down loaded at www.mymopar.com.

Dave

 

[72polarbear]

With the 318 engine, you are most likely going to have the 904 series transmission. You can use the modern ATF 4 in this transmission and the 727 series. Be sure to drain the torque convertor, replace the filter and do a band adjustment when you service the transmission. The torque convertor drain can be accessed via the small removable plate on the sheet metal cover on the lower part of the bell housing. If the transmission has been rebuilt at some point a torque convertor without a drain may have been installed. Service procedure is in the FSM which can be down loaded at www.mymopar.com.

Dave

The engine has been swapped to a 360 but thank you

 

[IOLA KID]

The parts book lists 3515873 as an A94-1 early style with 318 c.i.d. engine. It does matter much as 70's 94A-1, 904, and 727 use the same neutral safety/backup light switch.

 

[72polarbear]

The parts book lists 3515873 as an A94-1 early style with 318 c.i.d. engine. It does matter much as 70's 94A-1, 904, and 727 use the same neutral safety/backup light switch.

I looked at the pan, it’s squared shape with a cut corner, and it has 14 bolts. Is that what the 904 is?

 

[MrMoparCHP]

With the 318 engine, you are most likely going to have the 904 series transmission. You can use the modern ATF 4 in this transmission and the 727 series. Be sure to drain the torque convertor, replace the filter and do a band adjustment when you service the transmission. The torque convertor drain can be accessed via the small removable plate on the sheet metal cover on the lower part of the bell housing. If the transmission has been rebuilt at some point a torque convertor without a drain may have been installed. Service procedure is in the FSM which can be down loaded at www.mymopar.com.

Dave

A 69 Polara that I have with a 318 had a 727


Alan

 

[MrMoparCHP]

The easy way to tell is the pan shape.

This is a 904

This is a 727

Alan

 

[Lefty71]

It is a 1972 vintage A-904 for a 318 engine, early standard duty unit.

Your trans was the 35th unit built on November 26th, 1971 for the 1972 model year.

I don't think you'll have any issue running a Dextron/Mercon trans fluid. Type "F" would be best, IMO.

 

[FURYGT]

I have had two 727 transmissions rebuilt recently by a reputable transmission shop that also drag races vintage nitro funny cars. He recommends a cast pan and Dextron 6 transmission fluid. He told me that the type F transmission fluid does not provide adequate lubrication in high temperatures. One of the transmissions that I had rebuilt burned up and it had type F in it and only had around 3,000 miles on the transmission.

 

[CBODY67]

The Chrysler spec fluid for TFs back then was Dexron, which evolved into Dexron III. The replacement for that is the syn Dexron VI. The latest Dexron is backward compatible all the way to 1949, fwiw. The referenced Mopar atf is syn, too, as I understand it. The Dexron III is no longer licensed, but can still be found under "Multi-Makes" fluid, but the bottle MUST mention "GM vehicles" as some similar atf mentions "Hondas and such instead". ACDelco calls it "Type III" atf.

Many hot rodders of the later 1960s and earlier 1970s liked to use Ford Type F atf as it had an initial "bite" that was a bit like a "shift kit in a can", or sorts. Other than that, no real benefit of using it.

To me, the "safe bet" is the Dexron III atf, with the newer (and more costly) Dexron VI being next. Otherwise, a "multi-make" atf which specifies "GM vehicles" on the bottle.

Not to sound flaky, but to me the ATF+ fluids were developed for the electronic valve body Chrysler transaxles (i.e., UltraDrive and such), which had particular friction modifiers in them so those transmissions would live a long and great life. But I suspect they were/are also used in the later TFs behind Cummins diesels in pickup trucks. Did the later seal and friction composition change to better tolerate these fluids, compared to earlier designs? As I understand it, the orig ATF+3 was semi-syn for the seal compatibility reason?

CBODY67

 

[Toolmanmike]

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[413]

Dexron doesn’t have a T in it. It is the best ATF for these.

Type F is not a good fluid, poor lubrication qualities.

ATF+4 is just wrong for these TF 904/727’s also.

yes folks dump both of these wrong fluids in them like they are the best, they are not.

 

[Toolmanmike]

Dexron doesn’t have a T in it. It is the best ATF for these.

Type F is not a good fluid, poor lubrication qualities.

ATF+4 is just wrong for these TF 904/727’s also.

yes folks dump both of these wrong fluids in them like they are the best, they are not.

Well said.

 

[Lefty71]

One of the transmissions that I had rebuilt burned up and it had type F in it and only had around 3,000 miles on the transmission.

I don't care what anyone says, there's more to that story than just the fluid.... my two cents.
Type "F" has less additives, not less lubrication.

 

[413]

I don't care what anyone says, there's more to that story than just the fluid.... my two cents.
Type "F" has less additives, not less lubrication.

I have seen ATF tests that say the type F does not lubricate well.

In 80’s auto mechs schools, teacher said they would put type F in bad transmissions to keep them going a while longer due to the low lubricity of the fluid the trans would slip less.

he also stated the hard core drag racers would use it so the trans would last longer.

now a days everyone does all those things so we have 15 second street cars with type F fluid.

At the drags every week in the 90’s and building TF trans for racers and street cars, I could not talk these fools OUT of Type F, they all wanted it. I told them I use DEXRON III with zero problems in my cars.

Why do you want or need Type F?
”Because that’s what everyone says to use.”
”are these people transmission builders?
do they know what’s going on inside?”
”Well, No”
Oh, OK then.

 

[493mike]

I use ATF+4 in all my stock rebuilds. I have it in my 1965 Coronet. Check out the fluid specs and you will be impressed.
Mike