Measuring the transmission fluid level (727)

[The Goose]

My mentor taught me that way when I was 16.
Old timer transmission rebuilders who remember 727's have told me the same.
They beat it into me.
I have the scars.
You guys do it your way.

I totally get it. It’s like radiator caps. I was taught non vented goes on a catch system and a vent lever cap is for someone who likes dumping coolant in the dirt. I’ll never use a lever cap with a catch system. You’re NOT crazy, you’re just real world experienced...

 

[system11]

I respectfully submit my evidence...

This is the exact procedure I followed, although it was idling for about 30 minutes and then had a 10 minute drive up & down the road, then left idling again & checked. Adding just over a pint left me with the same thing I had when I started, a small bead of oil about 1cm long on the twist in the stick, under the low line, and a smear on the lower side of the stick.

A comment someone made about stalling - I'm not familiar with what that implies with an auto, but a couple of times when I had my foot on the brake and put it into 1st gear it nearly choked and died on me, despite being fully warm. Is that what was meant? It did this once and started behaving again.

 

[cantflip]

Sheep....

View attachment 232131

 

[CBODY67]

Key things, regardless of the method used:
1) Trans operates as it should, hot or dead cold, reliably
2) Checking procedure is constant, regardless of how it's done
3) Should be safer when done with the vehicle in "N" rather than "D", even with the parking brake firmly applied. A helper applying the foot brake rather than rely upon the parking brake?
4) Keep the fluid level in a range where things work well, but not too much as eruptions could occur our the dipstick tube under extreme fluid-heating activities (extended trailer towing in hilly conditions, for example) Fluid is heated more during extended "coast-down" situations, although longer periods of extended "power" can also do similar. Starting with too much fluid doesn't help matters. By observation, the eruptions usually happen through the dipstick tube rather than the case vent.

When every thing's "right", enjoy the heck out of it. But get to that point first.

CBODY67

 

[70bigblockdodge]

a small bead of oil about 1cm long on the twist in the stick, under the low line, and a smear on the lower side of the stick

This is low on fluid.
Add more fluid.

a couple of times when I had my foot on the brake and put it into 1st gear it nearly choked and died on me, despite being fully warm. Is that what was meant? It did this once and started behaving again.

Check ignition timing and raise curb idle.

 

[Mudeblue]

727 hold 5 quarts or 10 pints! Keep adding and test in neutral. If you do consider to test in drive, that should end all of your problems!

 

[commando1]

The only reason all the literature tells you you to check the ATF in Neutral because they know people will run over themselves if done the technically correct way in Drive.
Seeing as most people done even know to check when the engine is running, I believe it.

 

[The Goose]

One reason for this - - - lawyers.

 

[CBODY67]

To be sure, you COULD check the atf level when the car is in park and engine not running. Just need a different "FULL" mark AND ensure consistency of converter drain-back situations. No matter how it's checked, consistency of method is important. Fewer variables exist with the engine "hot" and "running" AND in a particular gearshift position. You could even use "R"!

CBODY67

 

[CBODY67]

727 hold 5 quarts or 10 pints! Keep adding and test in neutral. If you do consider to test in drive, that should end all of your problems!

There are usually two capacity amounts. One for "dry", as in overhaul. The other one for "fluid change", which is generally less than the "dry" spec.

CBODY67

 

[70bigblockdodge]

No no no no no no!.
You check the fluid while it is Drive!!!
I will argue to the death on this.

It's only a couple of ounces worth of fluid to engage the pistons. If that is making a difference in the operation of the trans you are headed for bigger problems.
Put a trans-go shift kit in it at rebuild time with the mod to allow the converter to fill in park and you can just check it in park and not run yourself over, or have to fix E brake.
Yes, it would be more accurate, but we can always use brain cells to adjust for neutral.

 

[commando1]

Didn't know there was going to be so many Flat Earth denyers on this or I wouldn't have brought it up.
If it slips,, keep adding ATF until it doesn't.

 

[Gerald Morris]

The only reason all the literature tells you you to check the ATF in Neutral because they know people will run over themselves if done the technically correct way in Drive.
Seeing as most people done even know to check when the engine is running, I believe it.

Checking when in Drive will give you the most accurate reading to be sure. I've done both in D or neutral, and see it makes about a quarter inch difference, reflecting how a little more fluid gets shunted around for D I reckon. Being slothful, I usually just do neutral reads. If you've got things tuned right and a decently low curb idle, the emergency brake holds them in place just fine in Drive, as you doubtless know....

 

[bajajoaquin]

The reason for checking in Neutral is that's the way to get a consistent reading. In Neutral, the pump is not engaged, so the oil will drain back into the pan. In Park, the pump will be pumping away. How much has it pumped into the rest of the system? Don't know. How long has it been pumping? What's your idle speed set at? Etc. However, if the transmission is hot and in Neutral, you can eventually get it to all drain back into the pan and get a consistent reading.

Because of that, Neutral will also be the highest reading. If it's reading low in Neutral, it's low. Add more.

 

[system11]

So yes, it was low - I put another 1.5 pints in and the level is about 25% over the low mark when fully warmed up in neutral. Strange thing the gearbox makes quite a hard shift now, but with the brake held switching through the gears doesn't seem make it want to stall as much. Doesn't seem to be leaking so I guess the previous owner just never filled it up enough.

 

[Trace 300 Hurst]

A comment someone made about stalling - I'm not familiar with what that implies with an auto, but a couple of times when I had my foot on the brake and put it into 1st gear it nearly choked and died on me, despite being fully warm. Is that what was meant? It did this once and started behaving again.

No, that is not what is meant by "stall" when referring to auto transmissions. When your engine is "stalling out" or perhaps just hesitating when you apply throttle, that is (typically) a fuel or ignition issue and has absolutely nothing to do with the transmission.

What is meant by "stall speed" is the RPM that the torque converter limits the engine to when you hold the brakes and rev the engine when it is in gear (Drive or 1st). With a stock 440 in a C-body, this is generally around 2200 revs, give or take 200. With a higher power output (meaning its torque rating) engine like a Hemi, that number might be 2800 RPM. If a 360 or a 383 2 bbl is in front of the torque converter, the stall speed might be only 1900.

In general, the diameter of the converter determines the stall speed with a given engine. [The internal design of the fins is also very important, but for our purposes that applies to highly engineered aftermarket race converters, not OEM units.] The smaller the diameter the higher the stall speed (again, for a given engine). Think of it that the larger diameter converter has more "muscle" to hold back the engine RPM against the torque being generated. Our converters are either 11 3/4 or 10 3/4 inch, depending on your engine, with the 440 performance engines having the 10 3/4 unit for a higher stall speed and thus better "off the line" performance (by allowing more revs for the hotter cam's torque curve, yada yada). Do you want to really feel a kick when you let off the brakes? Install an aftermarket 9 inch converter that will allow a stock engine to rev to 4000+ RPM against the brakes. Release brakes.....away you go with the engine making maximum torque. Nice.

But you still need the correct amount of trans fluid!!!

Here's the full story from the FSM. Please note that these stall numbers assume a properly tuned engine (see bottom line of first picture) that is capable of making its full power. If your engine is a stumbling, stalling, pinging piece of crappola, the stall speed against the brakes will be low. If your engine is an aftermarket 540 inch torque monster , it'll probably spin that converter to 3800 before it breaks it.

 

[Trace 300 Hurst]

Also: If you're thinking that commando might be right but you don't want to do the "in Drive" thing, simply carefully fill right-up-to-and-just-including the FULL line. That'll split the diff and you'll be just fine.

Also, also: Please, please never use the word "stahl" when discussing torque converters. You see this all the time on the Interweb either because the writer is illiterate and/or is confusing the whole issue with exhaust headers made by the great drag racer Jere Stahl. For that matter, I can recall opening up Autotrader and other rags in the 70s where guys were using "stahl" when discussing an aftermarket "high stall" converter, so apparently there were dumbasses before the 'web.....

 

[system11]

I'm thinking the carb is probably all kinds of incorrectly set up - once warm (they put a manual choke one on a car that needs an auto) it behaves normally but sometimes any amount of load (say, brakes on and putting in drive) makes it stumble badly. It also doesn't have the power I'd expect from a 383 engine, it's running like a 318 at best.

 

[Trace 300 Hurst]

I think your thinking about that carb is correct, probably a knackered accelerator pump diaphragm as I think others mentioned above. And dirt in the circuits, maybe.

That carb needs 1) a very good rebuild by someone who knows carburetors or 2) a rubbish can.

 

[system11]

The carb is brand new as far as I can tell, I think it was "buy it, fit it, it starts - ok done" One of those Edelbrock Thunder series. I'll be replacing it with an auto choke model next year so at least it's in good enough shape to resell later.