Automatic Transmission Fluid

[ja17]

Thought this may be of interest;
I have a Factory Service Bulletin dated August 1972, the subject is; Automatic transmission fluid and change intervals.
It states;

"Up to now, three different types of fluid were specified for the various automatic transmissions. However, we have found that the transmission fluids (ATF) Dextron B, according to page 236.4 of the Fuel and Lubrication Manual....."

It goes on to say this about the two planetary gear set four speed transmissions used in the W113 cars;

 " Automatic transmissions with 4-speed, 2-planetary gear sets, (When a new transmission is installed, ATF type A, Suffix A, which is available from our parts Depots must be used. For later topping off or fluid changes, either type A or ATF Dextron B may be used."  

The literature goes on to list the entire W113 series and other models of the era with this type of transmission.
Concerning transmission change intervals the literature states;

 "For transmissions K4C 025, K4A 025, and K4A 045, with oil filter, (they are marked "F" behind the transmission no. on the Model plate), the fluid and filter element should be replaced under normal conditions every 30,000 miles.".....

It goes on to say that under severe operating conditions the fluid should be changed every 12,000 to 15,000 miles without changing the filter.
Since this bulletin (1972) other changes for acceptable fluid types may have been approved also.

Joe Alexander
Blacklick, Ohio

[rwmastel]

Joe,

Can you rate the difficulty of an automatic transmission fluid & filter change?  I'm sure there are people who do their own engine oil changes and other service, but have not done a transmission service.  Is it difficult?  Does it requrire any special tools?

Thanks,

Rodd
Powell, Ohio, USA
1966 230SL, Euro, Auto, Leather, both  tops
1994 E420

[ja17]

Edited: Transmission dry capacity is about 5 qts. Less fluid is used during subsequent change intervals.


Hello Rodd,
The transmission service is a little more difficult than an oil change. As far as tools a 5 mm allen wrench is needed to drain the torque converter, a 11 mm socket and ratchet for the 16 pan bolts, a large wrench (27mm I think?)for the oil filler tube on the side of the transmission, a 10 mm wrench, a 19mm wrench to unfasten the drain plug on the pan. A screwdriver is needed to remove the filter.

A new filter kit is needed which includes a new cork gasket and filter. This pan gasket should be replaced at each service. Do not be tempted to use sealer and the old gasket since the sealer may enter the transmission. Always check the two rubber transmission hoses at the radiator before beginning the job. If they are dried out or damaged it is a good time to replace these also. They are fairly inexpensive. If one blows your stranded.

Drain the transmission fluid from the pan, remove the two 10 mm bolts holding the metal grate over the opening in the bottom of the bell housing. Rotate the engine by hand until the drain plug on the torque converter is down and remove it using the 5mm allen wrench. When all the fluid is drained, unfasten the transmission oil filler tube from the side of the pan (a second skinny wrench may be needed to hold the fitting). Remove the sixteen 11 mm bolts holding the transmission pan in place and drop the pan.

The filter is held in place with a slotted screw. Check that the 11 mm bolts are snug on the valve body unit above the filter. You can torque them if you have an small inch pound torque wrench. Otherwise just make sure they are all snug. Clean and dry the pan, install the new filter and pan with the new cork gasket. Install the torque converter drain plug, filler tube etc.

Start off adding about three quarts. Briefly start the engine to pump fluid up into the torque converter. Stop the engine and finish filling. To check the level the car must be on perfectly level ground, in park, running and engine warm. Move the shifter through the gears before the fluid check. Remember that the two marks on the transmission dip stick represents 1 pint!(not one quart). Running the transmission overfilled  can cause damage. If you do overfill, it may be easier to remove fluid by loosening one transmission hose at the radiator to allow some fluid to escape. Test drive and recheck the level.

Joe Alexander
Blacklick, Ohio

[rwmastel]

Joe,

Thanks for the great detail!  I'll be putting this on my Spring Maintenance List.

Rodd
Powell, Ohio, USA
1966 230SL, Euro, Auto, Leather, both  tops
1994 E420

[graphic66]

I am going to change my automatic transmission fluid in my 66' 230SL. I went to purchase the fluid- Dexron B and the parts person said to use Pennzoil Multivehicle ATF Synthetic blend. Does anyone know if this is correct or if not what type and brand would be better. I have a new filter and gasket. Thank you.

[J. Huber]

Hi J.P. I just checked my 230SL manual. It says from dry, the capacity is 10 US pints -- which equates to 5 quarts. It states that "refill" capacity is 7.9 US pints...

James
63 230SL

[Benz Dr.]

I think all trans fluids made today have to be compatible with each other. I just use ordinary ATF. It's never let me down.

 Lack of oil is more a problem than which oil you use.

Dan Caron's
 SL Barn
benzbarn@ebtech.net
 slbarn.mbz.org
  1 877 661 6061

[66andBlue]

I am reviving Joe's old post to find out what the current opinion or consensus is as to what ATF type to use.  As Joe wrote the original MB recommendation was ATF Type A.  Here is a link suggesting that Type A is now replaced by Type D:
http://www.valvoline.be/index.asp?pageid=772ce3a94b78491d9cbcb33efa9c6474&q=atf
Any comments?  What is your favorite ATF?
Also what does Dexron III/Mercon mean?

[Benz Dr.]

I put as much as the trans will hold without overflow before I start the engine and then I keep adding oil while the engine is running. The oil will go into the converter because the pan only holds about 2 liters.

It will appear to be overfilled if you fill without the engine running after checking the fluid level. It will draw the level down and be pretty close to the right level after the converter fills. If you check the level on a cold trans without the engine running it will appear to be too full but once the engine starts it will lower to the right level on the stick. All level checks should be made on a warm running system.

[66andBlue]

quote:Originally posted by Benz Dr.
I put as much as the trans will hold ....

Hello Doc,
but what are you putting in these days, brand and type?
I don't believe it is distilled water, is it?

[Benz Dr.]

My distillery is closed for the summer. Not being a drinking man I don't know much about such things. I am somewhat partial to Pelee Island wine. Some of the best we have to offer.

I use ordinary ATF. I also use AMSOIL synthetic in the 5 speed gear box on the Red Rocket. All ATF has to be compatible and mix with any ATF these days. Put something in it, whatever you do......

[Mike]

I had an interesting experience involving my manual transmission and leaking ATF.  After rebuilding the transmission a couple of years ago, it began to leak fluid.  I was disappointed because I thought that we had replaced all gaskets correctly.  This leaking continued until a few months ago.  I put  the car on the lift and checked the level, assuming that it would be low in light of the leaking.  When I removed the plug, it immediately "belched" out about a half of a pint of fluid onto the floor.  After that, I checked the level.  It was fine.  Ever since then, it has not leaked at all.  I guess that I had somehow had overfilled it when it was rebuilt.

[jszeman1]

Can anyone tell me what type of ATF should be used in a 4 speed manual transmission?  What is the capacity of the transmission.  Thanks, John