correct transmission fluid

[mikes456]

What is the correct transmission fluid for a 1973 A727 transmission. (Todays blends)
I will be replacing my steering box and in the past I would use transmission fluid can i still do this.
In the past I used dextron III for both componets steering box and trannie? There are a lot of types of fluid out there
I just want to get the correct one.

Thank You

MIke

 

[moparleo]

Has the transmission been rebuilt recently ?

 

[mikes456]

The tranmission has not been rebuilt recently it was rebuilt about 20 years ago but is about 1/2 a quart low.
I have over the years put dextron 3 in it. The pan has a very very small leak due to a stripped bolt.
This was built by Tom Chamberlin and is a full manual shift with a reverse shift pattern.
Not sure what he did but it shifts as hard as the day I put it in and the fluid is clean. I'm afraid to do a fluid change due to its age
that is why I never fixed the stripped bolt in the pan.

 

[moparleo]

The reason I asked, was that unless it was factory with no rebuilds, the type of fluid would depend on what material the replacement clutches were made from as the friction materials are constantly being upgraded. Normally the place that rebuilt the transmission would recommend the proper fluid for the rebuilt trans. The transmission fluid level should be kept at approximately 1 pint low. This is in either Neutral or Drive as the pump does not work when in Park. I always start my car in Neutral with the brake on. This gets fluid to circulate immediately. This eliminates the hesitation when first put into Reverse or Drive on initial start up. If you are worried about the trans fluid. All you need to do is drain the fluid into a clean container and use it to refill the trans after you repair the stripped bolt. Even if you use the old fluid again, you should replace the dirty filter.

Realistically though, if the transmission would start to slip with the fluid changed. It should be repaired properly any way. That is like not wanting to change the oil incase a lifter would start to tap. You are just trying to hide a potential problem instead of doing the right thing.
Let the trans pan be your guide. If you find a lot of metal debris, its time to fix it. If it is just dirty, replace with new fluid of the same type you have been using. It would be a good time to replace the pan with one that has a drain plug and put a magnet in the pan to trap metal debris. You might also want to drain the torque convertor as it holds a lot of the fluid.

 

[moparleo]

I noticed you are the same person with the fuel problem and are changing the steering pump. Has this car been sitting for a long period of time and you are trying to get her back on the road ?

If you are putting a new pump in it, you should use what ever is currently recommended by the pump manufacturer. The fluids and seals are much better today than way back when and it is not recommended to use transmission fluid instead of power steering fluid. What you can do is use the newer synthetic fluids on newly manufactured or rebuilt parts as the internals wil benefit from the synthetics superior lubricating and high temperature resistance to fluid breakdown.

Also a great time to replace the brake fluid if its been more than 3 years. The old brake fluids absorb water which greatly lowers the boiling point of the fluid which is what causes brake fade on long or high speed stops. The water also causes the insides of the metal brake components to corrode and rust from the inside out. Things like metal brake lines, pistons in the brake calipers, wheel cylinders, mastercylinder will all fail prematurely when the fluid is not changed regularly. The difference in the Dot designation on brake fuild is its resistance to high temperature, hygroscopic water absorbsion. The lowest is Dot 3. Which is the standard ,old brake fuild used before high performance brakes were used as standard on modern cars. The new brake systems with ABS brake pumps, thin rotors combined with high speeds put a lot of demands on the brake fluid.

 

[mikes456]

The car is road worthy and I drive the car a few times a month. Nothing is wrong with the transmission my problem is I can only find Dextron III/ Mercon instead of the plain Dextron III. My owner manual states to use Dextron. Can Dextron III/ Mercon be used to top off the transmission?. I may have said the car was restored 20 years ago in the previous posts. I never resolved the fuel issues but my work around was to keep a full tank of fuel in it, which is not a bad thing a car that is not a daily driver. The steering box started to leak last summer and the puddle in my garage is pissing me off. I will look at the paper work for for the steering box and see what it wants for fluid. The box is stained cherry red from what fluid was put in at the factory were it was rebuilt. Attached are to photos. Thnk foor taking the time to responed.

MIke

I noticed you are the same person with the fuel problem and are changing the steering pump. Has this car been sitting for a long period of time and you are trying to get her back on the road ?

If you are putting a new pump in it, you should use what ever is currently recommended by the pump manufacturer. The fluids and seals are much better today than way back when and it is not recommended to use transmission fluid instead of power steering fluid. What you can do is use the newer synthetic fluids on newly manufactured or rebuilt parts as the internals wil benefit from the synthetics superior lubricating and high temperature resistance to fluid breakdown.

Also a great time to replace the brake fluid if its been more than 3 years. The old brake fluids absorb water which greatly lowers the boiling point of the fluid which is what causes brake fade on long or high speed stops. The water also causes the insides of the metal brake components to corrode and rust from the inside out. Things like metal brake lines, pistons in the brake calipers, wheel cylinders, mastercylinder will all fail prematurely when the fluid is not changed regularly. The difference in the Dot designation on brake fuild is its resistance to high temperature, hygroscopic water absorbsion. The lowest is Dot 3. Which is the standard ,old brake fuild used before high performance brakes were used as standard on modern cars. The new brake systems with ABS brake pumps, thin rotors combined with high speeds put a lot of demands on the brake fluid.

 

[Chryco Psycho]

I thought we we talking about steering fluid ?
in which case I would use a steering fluid

 

[mikes456]

1. I am replacing the steering box so I will need to add fluid. In the past I always used transmission flluid which was Dextron III.
2. I also need to add a pint of tranmission fluid to my transmission. In the past I would also use Dextron III which I cannot find anywhere.

Dextron III-Mercon is on the shelf at stores near me. Can I use that in my transmission and also in the power steering pump?
Service manual and my owner manual state Dextron in the transmission that is why I have used Dextron III as it is backwords compatable.
When google info on this subject I get all different answers?

I thought if I posted here I would be a simple answer but I guess there is a lot of factors.

What do you put in your A727 transmission?

 

[moparleo]

It helps when you ask a question to tell us the rest of the story. When you say that the owners manual tells you to use a certain fluid, is this the cars original owners manual ? If so, the fluids have changed over the years. Since the trans was rebuilt, it may not necessarily use the original fluid anymore. What did the rebuilder recommend ?
Here is more info on the fluids.
http://en.wikipedia.org/wiki/DEXRON

 

[mikes456]

The manual is the orginal one that came with the car.
The rebuilder died two years ago.
Based on what I find in the store the Dexroniii / Mercon is the closest blend to the orginal dexron so I guess that is what I will use to top of transmission.
I just moved my car to a friends house who has a lift in the garage. The box with the steering box in has paper work I will see what they want in the steering box.

Thank You for your input and link

 

[moparleo]

I hope the info is helpful.

 

[Chryco Psycho]

Dex III Dex II Mercon , or Dex IV is fine .