Power Steering Fluid/ATF Question - PeachParts Mercedes-Benz Forum

Cr from Texas · #1 08-21-2009, 02:46 AM

A little searching will reveal that 123 owner's manual recommended the same AT fluid for both the transmission and the power steering. Current threads are of the opinion that the 25+ year old recommendations are out of date and current ATF contains newer additives that can cause the power steering to leak.

My favorite indy was not aware of this and raised this question which left me stumped:

"If the new formulations af ATF can cause the 123 power steering to leak, what should you be putting in the automatic transmission? If would have been built with the same type of materials for seals, o-rings, etc."

Comments?

Older formulations of ATF are hard to come by, what are you using?
Power steering fluid for the power steering but what about the automatic transmission?

tangofox007 · #2 08-21-2009, 08:22 AM

Quote:

Originally Posted by Cr from Texas

My favorite indy was not aware of this and raised this question which left me stumped:

"If the new formulations af ATF can cause the 123 power steering to leak, what should you be putting in the automatic transmission? If would have been built with the same type of materials for seals, o-rings, etc."

My sentiments, precisely. Every iteration of Dexron ATF has been advertised to be "backwards compatible" with the previous versions.

LUVMBDiesels · #3 08-21-2009, 08:26 AM

Quote:

Originally Posted by tangofox007

My sentiments, precisely. Every iteration of Dexron ATF has been advertised to be "backwards compatible" with the previous versions.

I use ATF in my power steering ( I think it is even M1) and have no problems...

Cr from Texas · #4 08-21-2009, 05:25 PM

So where is a response from all those members swearing not to use ATF in the power steering?

jaycodyp · #5 01-04-2010, 03:09 AM

Sound logic to me. Bumpin this one up.

toomany MBZ · #6 01-04-2010, 11:12 AM

I use power steering fluid in the power steering fluid reservoir. Maybe I'm overreacting, but I feel better.

leathermang · #7 01-04-2010, 11:58 AM

Quote:

Originally Posted by Cr from Texas

So where is a response from all those members swearing not to use ATF in the power steering?

You mean the ones that read the Factory Shop manual and pass on the warnings in it about the special ps fluid ?
Maybe they are still celebrating the holidays.... or getting ready for the big bowl game....

Cr from Texas · #8 01-04-2010, 01:39 PM

Quote:

Originally Posted by leathermang

You mean the ones that read the Factory Shop manual and pass on the warnings in it about the special ps fluid ?
Maybe they are still celebrating the holidays.... or getting ready for the big bowl game....

Leathermang, Did you read post #1? Is the new formulations of ATF also damaging seals in the old AT?

H-townbenzoboy · #9 01-04-2010, 02:26 PM

Quote:

Originally Posted by Cr from Texas

A little searching will reveal that 123 owner's manual recommended the same AT fluid for both the transmission and the power steering. Current threads are of the opinion that the 25+ year old recommendations are out of date and current ATF contains newer additives that can cause the power steering to leak.

My favorite indy was not aware of this and raised this question which left me stumped:

"If the new formulations af ATF can cause the 123 power steering to leak, what should you be putting in the automatic transmission? If would have been built with the same type of materials for seals, o-rings, etc."

Comments?

Older formulations of ATF are hard to come by, what are you using?
Power steering fluid for the power steering but what about the automatic transmission?

I just took a look at an owners manual for the 1985 300CD/D/TD lineup and under the Fuels, Coolants, Lubricants, etc. section, it lists "Automatic transmission fluid for automatic transmission" as the fluid of choice for the transmission, and "Automatic transmission fluid for power steering" as the fluid of choice for the power steering system. Their phrasing would lead you to come to the conclusion that there are different types of ATF for those applications, and a footnote for both listings states that you should consult your local MB dealer for recommended brands. 25 years have passed and we no longer have to go directly to the dealer, but can now pull up the same resources that the MB dealer uses to determine what the proper fluids are. This is what I'm referring to: http://bevo.mercedes-benz.com/bevolistenmain.php?content_action=showselect&navigation_path=bevolisten&blatt=231.1&suchbegriff=

I took a look at the recommendations for the transmission fluid and power steering fluid and it suggests ATF from various 236.x lists for the 722.3/4 transmissions found in most of our cars, and ATF from ONLY list 236.3 for power steering systems. For some reason, MB lists those fluids under the header of ATF, yet they are all intended for use in power steering systems ONLY. So the fluids in 236.3 are the "automatic transmission fluid for power steering" as referenced to in the manual. Maybe they're not the red dyed Dexron/Mercon III fluids that come to mind when WE think of ATF and pour in our transmissions, but MB calls them ATF and lists them as the fluids to be used in the power steering system.

tangofox007 · #10 01-04-2010, 02:27 PM

Quote:

Originally Posted by leathermang

You mean the ones that read the Factory Shop manual and pass on the warnings in it about the special ps fluid ?

As I recall, they were reading Popular Mechanics.

Eric · #11 01-04-2010, 04:25 PM

off the shelf power steering has worked great in my 240D for years!

NoCalMer · #12 01-04-2010, 04:38 PM

If you have power steering fluid in there and it is not leaking, I would continue using power steering fluid. I switched to red ATF and after about 30K it started to leak slowly from the box. I am now back to power steering fluid to see if I can slow or stop the leak.

phyxer · #13 01-04-2010, 07:03 PM

When I replaced the power steering fluid and filter a few weeks ago, I went to NAPA and they had power steering fluid. Since I was replacing power steering fluid, I bought power steering fluid. When I replaced the trans fluid and filter in the automatic, I bought trans fluid. I figured I had to buy some kind of fluid to do the jobs. I have really never had or heard of anyone having problems putting power steering fluid in the power steering application. I would not put power steering fluid in my trans though.

Cr from Texas · #14 01-04-2010, 07:15 PM

Quote:

Originally Posted by H-townbenzoboy

I just took a look at an owners manual for the 1985 300CD/D/TD lineup and under the Fuels, Coolants, Lubricants, etc. section, it lists "Automatic transmission fluid for automatic transmission" as the fluid of choice for the transmission, and "Automatic transmission fluid for power steering" as the fluid of choice for the power steering system. Their phrasing would lead you to come to the conclusion that there are different types of ATF for those applications, and a footnote for both listings states that you should consult your local MB dealer for recommended brands. 25 years have passed and we no longer have to go directly to the dealer, but can now pull up the same resources that the MB dealer uses to determine what the proper fluids are. This is what I'm referring to: http://bevo.mercedes-benz.com/bevolistenmain.php?content_action=showselect&navigation_path=bevolisten&blatt=231.1&suchbegriff=

I took a look at the recommendations for the transmission fluid and power steering fluid and it suggests ATF from various 236.x lists for the 722.3/4 transmissions found in most of our cars, and ATF from ONLY list 236.3 for power steering systems. For some reason, MB lists those fluids under the header of ATF, yet they are all intended for use in power steering systems ONLY. So the fluids in 236.3 are the "automatic transmission fluid for power steering" as referenced to in the manual. Maybe they're not the red dyed Dexron/Mercon III fluids that come to mind when WE think of ATF and pour in our transmissions, but MB calls them ATF and lists them as the fluids to be used in the power steering system.

Townboy,
That's exactly the information I was looking for. I'll print your reply and give to my indy. I'm sure it will cause him to change how he is servicing some older cars.
Thanks,

ah-kay · #15 01-04-2010, 07:19 PM

When I bought my 300D the power steering fluid looks redish and I always wonder why. May be it was ATF in there. I topped it up with normal power steering fluid, actually I top up all my project cars with normal run of the mill stuff p/s fluid and I do not have any issues.

I presume it would not do any harm by mixing it?? Any info would be appreciated.