Couple simple tranny questions - 69 Coronet

[pearljam724]

Please excuse the dozens of questions I might be asking in the near future, lol ! I just bought my car and I’m trying to learn as much as possible. My car is an automatic on the column. I’ve yet to verify myself, but was told it had the original transmission and rear end. I believe if that is correct the tranny would be a torqueflite 727 and rear end would be a 273 ? Is that correct ?
What tranny fluid is recommended, Type F ok ?
I’ve learned through research that many cars that have aftermarket parts are prone to kick down not operating properly. Mine is no exception.
Through a lot of digging on the net, Ive come to learn that when the carb throttle body is wide open throttle the linkage attaching to the tranny needs to be at its full swing for the pump to build pressure for the kick down to work properly.
What are the best suggestions to get the kick down operating correctly again ? I know they sell aftermarket kick down cables. Is that the best option for me ? Or would it be best to take the car to a trusted transmission guy that’s been rebuilding transmissions for decades that I know ? Im no mechanical fool, but this is new territory for me. Thank you for any insight, suggestions and most of all experiences shared.

 

[Coronutcase]

I’ve yet to verify myself, but was told it had the original transmission and rear end. I believe if that is correct the tranny would be a torqueflite 727 and rear end would be a 273 ? Is that correct ?

Not necessarily. It could have a 904 Transmission. The most common would be a 727 Torqueflite. As far as your gears, there is a wide range. I think a 3:23 would be more likely and is probably the most common. Is this a big block car? Your fender tag should give you all that information. Hopefully it's still there.

I'll let some other more knowledgable folks answer the rest of your questions.

 

[pearljam724]

That was very helpful, thank you. Yeah the tag is still on the fender. I decoded 4 or 5 codes the day after I bought it. Don’t remember tranny or rear end being any codes I deciphered. Where is the rear end model stamped at on the axle ? The car originally had a 318. It has a rebuilt 360 in it now with a mild cam. 4 barrel Edlebrock and Edlebrock intake. Doesn’t set the world on fire. But, runs very good for a cruiser. I feel it would run so much better if I sorted out the kick down.

 

[Billccm]

My recently retired transmission guy claims ATF+4 is the best for all mopar automatics old and new.

The kick down is a clunky design in my opinion. Yes, it works when adjusted and works well, but I prefer this:


https://www.bouchillonperformance.com/inc/sdetail/589

 

[oldbee]

Kinda disagree w/Bill. Don’t trust the cables as much myself. If you have oe linkage(&adjusted right) they work fine. Start out with adjustment from the FSM and go from there.

 

[threewood]

Welcome! Best purchase you will ever make for your car is a factory service manual
It shows how to adjust the kickdown correctly, although you can find videos of guys doing it on line as well.

I use Type F in both my old Mopars without issue.

 

[66Satellite47]

Having a Factory Service Manual is extremely helpful. You may have to stare at it quite a while, but it sure gives lots of info. Kickdown linkage is always a pain. But when you get it where you want it, good. Aftermarket carbs take a lot playing.

 

[oldbee]

Welcome! Best purchase you will ever make for your car is a factory service manual
It shows how to adjust the kickdown correctly, although you can find videos of guys doing it on line as well.

I use Type F in both my old Mopars without issue.

Ya gonna get stuff started with the type F post!! Luv it myself.

 

[beanhead]

That was very helpful, thank you. Yeah the tag is still on the fender. I decoded 4 or 5 codes the day after I bought it. Don’t remember tranny or rear end being any codes I deciphered. Where is the rear end model stamped at on the axle ? The car originally had a 318. It has a rebuilt 360 in it now with a mild cam. 4 barrel Edlebrock and Edlebrock intake. Doesn’t set the world on fire. But, runs very good for a cruiser. I feel it would run so much better if I sorted out the kick down.

If it was originally a 318 car it came with the 904 transmission. 727s are big block transmissions except for a special 727 that was mated to the high performance 340s.(check out the thread at the very top of the Engines & Transmissions forum--some good info). As far as the rear, if there is no cover bolted on the backside of the center section it is an 8 3/4 and will have the casting number on the side of the carrier, by the end of the drive line. More than likely it will end in '741'. The only way to truly determine the gear ratio, in any style rear, is to raise the rear off the ground, put the car in neutral, and watch how many times the driveline turns for one complete turn of the rear wheels..for example if the driveline makes two and three-quarter turns in the time it takes the wheel to turn once then that would be the 2.76 rear.

 

[66Satellite47]

In the '70's & '80's I mostly ran type F. Not sure I really saw any difference, My current trans builder recommends Dex/Merc. Seems like a mix?

 

[oldbee]

If it was originally a 318 car it came with the 904 transmission. 727s are big block transmissions except for a special 727 that was mated to the high performance 340s.(check out the thread at the very top of the Engines & Transmissions forum--some good info). As far as the rear, if there is no cover bolted on the backside of the center section it is an 8 3/4 and will have the casting number on the side of the carrier, by the end of the drive line. More than likely it will end in '741'. The only way to truly determine the gear ratio, in any style rear, is to raise the rear off the ground, put the car in neutral, and watch how many times the driveline turns for one complete turn of the rear wheels..for example if the driveline makes two and three-quarter turns in the time it takes the wheel to turn once then that would be the 2.76 rear.

Au contraire- bean forgot some taxicabs!!! Think there was even /6 727's in some of them.

 

[beanhead]

Au contraire- bean forgot some taxicabs!!! Think there was even /6 727's in some of them.

Oh! That makes sense, since they were probably considered 'heavy duty'... Now if I remember right there were some small block equipped trucks that got the 727 also I think?

 

[66Satellite47]

Lots of small block 727's. many cars, trucks, vans.

 

[Dipstick]

If it was originally a 318 car it came with the 904 transmission.

Not necessarily, the OP has never stated the year of the car.

 

[Officer Higgins]

78 dodge truck slant six 727 transmission. Great old truckster!

 

[beanhead]

Not necessarily, the OP has never stated the year of the car.

Read the title

 

[pearljam724]

I have another question pertaining to this topic. Let’s just say the original transmission ( 904) and original rear end ( 323 ) is infact in the car and that’s what they are. Which I have no reason not to believe at this point. Due to other things I verified. Would a 440 engine be a straight swap and would that tranny and rear end handle the power increase ? I understand that the combinations may not be the most desirable. But would it be any easy swap without fear of damaging tranny or rear end due to the increased horsepower ?

 

[beanhead]

The 8-3/4 can take plenty of power, unless the engine's highly modified (the 8-3/4 was stock on many 727-equipped Hemi cars). But, the 904 will not bolt up to the big blocks...you'll need a 727 and different length (shorter) driveshaft.

 

[Dipstick]

An original 318/904 '69 Coronet would likely have a 8 1/4" read end. See if the rear end has a removable lid on the rear.

 

[pearljam724]

Thanks, guys. I just now had a minute to look at the rear end. No bolt on differential cover. It looks welded on from the factory. There is a big serial number on the driver side of the yoke cover ? Can’t quite read it until I raise the car.