Chrysler Power Steering - Mobil 1 ATF?

[OVERKILL]

My power steering fluid calls for Mopar Power Steering Fluid +4 or Mopar ATF +4 in the Charger. Though I find that when it is really cold, the steering gets funky until it warms up. I have Mobil 1 ATF in the Expedition and it has no problems at the same temperature.

Just wondering if anybody has deviated from the Chrysler spec'd fluid successfully? Or should I just try to find the Mobil ATF+4 fluid, which seems to have better cold temp specs anyway (8,800cP @ -40C vs 10,040cP @ -40C for M1 synthetic ATF).

 

[anonobomber]

I'd stick with ATF+4 as that is what I use in my 300. You could be starting to experience "morning sickness" on your steering rack. It is a common issue with steering racks as they get older though I have yet to experience it on my 300 at 141,500 miles. When was the last time you had the ps fluid flushed?

 

[OVERKILL]

I don't think it was ever flushed, that's why I was thinking of changing it, LOL!

Is the morning sickness it being really funky? Like it'll go loose and hard loose and hard and I think the column squeaks when it is around -20C. The truck on the other hand just steers like a champ, and its steering system has like 200,000 miles on it

When it isn't -20C, like say it is -15C, the steering will just be hard for the first bit until it warms up. It doesn't make any noises or anything, just hard steering, like it has very little assist.

 

[901Memphis]

ATF+4 is supposed to have very good cold flow properties, not sure if that is an upgrade or a downgrade.

 

[OVERKILL]

Well even between ATF +4 variations there seem to be differences.

For example the Mobil ATF +4 is slightly better in the cold than the Valvoline version

Not sure on the Mopar-branded stuff.

 

[901Memphis]

That's weird because i was told all ATF+4 was exactly the same.

 

[OVERKILL]

Originally Posted By: 901Memphis
That's weird because i was told all ATF+4 was exactly the same.


If you look at the PDS's you'll see that isn't the case.

Visc @ -40C:

Mobil: 8,800cP
Valvoline: 9,000cP
CAM2: 15,000cP
Castrol: 8,500cP
Pennzoil: 9,300cP

 

[Rand]

Its possible the additives and friction properties are nearly the same as its a licensed formula. That does not mean everyone makes it from the same basestock(s)

 

[OVERKILL]

Originally Posted By: Rand
Its possible the additives and friction properties are nearly the same as its a licensed formula. That does not mean everyone makes it from the same basestock(s)


Exactly. They all meet the spec, but there are obviously some differences to yield the discrepancies noted on cold temp performance.

 

[OVERKILL]

Also, it looks like the Castrol ATF is probably the best..... That hurts me to say, LOL!

 

[zrxkawboy]

Any syn ATF will work fine. The PS system doesn't care about the extra FMs in the +4.

 

[OVERKILL]

Originally Posted By: zrxkawboy
Any syn ATF will work fine. The PS system doesn't care about the extra FMs in the +4.


That was my thought, however, the ATF+4, particularly the Castrol and Mobil fluids, appear to have excellent cold flow characteristics, better than the AMSOIL Synthetic ATF, which is 9,755cP @ -40C.

 

[GSCJR]

I have the Havoline brand ATF+4 in my p/s that specs Dex3. I bought it when PartSource was clearing it out @ 1.67 a quart. Worked great the other day at -18c. Could be the characteristics of your system as opposed to the fluid selection.

Viscosity, Brookfield
cP at -40°C 8,380

EDIT: It's in my transmission right now. Not my p/s, oops.

Castrol import multi-vehicle is in the p/s, sorry.

 

[285south]

Originally Posted By: OVERKILL
I don't think it was ever flushed, that's why I was thinking of changing it, LOL!


Brake and power steering fluid should be replace every 2 years.

 

[DoubleWasp]

I've only encountered this problem due to belt issues in Chrysler. Don't know what it is about them, but they can slip belts like nobody's business without making a single noise.

When the rubber belt is hard, cold, and potentially moist in the morning, this could be a culprit.

Unless dealing with a system of unknown maintenance, or epic neglect, fluid condition or specs would be one of the last places I looked.

 

[DoubleWasp]

I've only encountered this problem due to belt issues in Chrysler. Don't know what it is about them, but they can slip belts like nobody's business without making a single noise.

When the rubber belt is hard, cold, and potentially moist in the morning, this could be a culprit.

Unless dealing with a system of unknown maintenance, or epic neglect, fluid condition or specs would be one of the last places I looked.

 

[OVERKILL]

Originally Posted By: 285south
Originally Posted By: OVERKILL
I don't think it was ever flushed, that's why I was thinking of changing it, LOL!


Brake and power steering fluid should be replace every 2 years.


Lucky for me I've only had the car a few months then eh?

 

[OVERKILL]

Originally Posted By: DoubleWasp
I've only encountered this problem due to belt issues in Chrysler. Don't know what it is about them, but they can slip belts like nobody's business without making a single noise.

When the rubber belt is hard, cold, and potentially moist in the morning, this could be a culprit.

Unless dealing with a system of unknown maintenance, or epic neglect, fluid condition or specs would be one of the last places I looked.


Thank you! That actually makes a lot of sense, particularly in regards to the "surging" feeling of the assist when it was extremely cold, which would be getting/not getting assist with the slip, right?

Will look at that! Thanks again!

 

[Garak]

Originally Posted By: OVERKILL
Or should I just try to find the Mobil ATF+4 fluid, which seems to have better cold temp specs anyway (8,800cP @ -40C vs 10,040cP @ -40C for M1 synthetic ATF).

Maybe a flush and fill of the Mobil ATF+4 would be your best bet, along with checking the belt, as was suggested. I believe CT carries the ATF+4, as does PartSource. Imperial Oil would probably want you to buy a case.

Does the manual list alternatives? In the G37, I can use Nissan PSF, Matic J (Matic S now), or Dexron VI, which is what is in there now.

 

[Joel_MD]

Originally Posted By: zrxkawboy
Any syn ATF will work fine. The PS system doesn't care about the extra FMs in the +4.

I agree with this. I have a 2007 Dodge Ram that calls for the same power steering fluid as your Dodge. I've been using Amsoil synthetic ATF for the power steering and it works very well. I have one of those Mightyvac brake bleeders, and about once a year I go around and suck the PS fluid out of all my cars' reservoirs and refill with clean fluid. Doing it that way keeps the fluid very fresh.