OK to mix new 722.9 (3353) fluid with old 722.6 fluid during trans service?
 

On my low mileage '00 c280, I plan on just dropping the pan, replacing the filter, adding a magnet and topping off the fluid this weekend. Unfortunately I have no converter drain plug.. :( I understand that the new 3353 fluid is backwards compatible with older transmissions, just don't know about the mix.

My question is would it be a good, bad or OK idea to top it off with the new 722.9 (3353) fluid or stick with the older spec fluid?

Bonus question: Does it matter where I stick the magnet in the pan? I understand there are electronically controlled solenoids nearby on the valve body..

Since the new stuff is reputedly very expensive AND you're not going to be able to get all the "old" fluid out I think you should just consider topping it off with the "old" style fluid. I don't think you'd be getting the full benefit (if any on a tranny not specifically designed for it) with your dilution.

If you DO decide to go that route please confirm the price of the new stuff? I think I read earlier somewhere around $25 a liter?! I guess though that when you can afford a 7-speed transmission it's a moot point.

The magnet is as thick as a refrigerator flat magnet or credit card. I haven't seen any instructions for placement other than just "...insert in the pan." It's good you're thinking about possibilities though:)

Thanks so much for the reply.

I thought the new 3353 fluid was actually cheaper than the old stuff, that's mainly why I was going to use it. If that's not the case, then I definitely won't.

As for the magnet, I've heard there's a larger, stronger, round magnet now available that I was planning on using, that was why I was concerned with it's placement.

I am not positive if the fluids can be mixed, but I am fairly certain that the new fluid is cheaper than the old fluid.

That's the only reason I'd be interested in using the newer fluid really, as I don't expect any benefits from the 2.5-3.0 liters of fluid I'd put back in after changing the filter.

However, I'd still really like to know whether or not it would be a bad idea to mix the two different formulas. Also, if makes a difference where I place the new, stronger, round magnet in the pan.

Anyone?

EDIT: I should also add that I've searched and searched the forums for the info about the compatibility or mixing of the two fluids before posting this question and found nothing more than the fact that the new fluid is backwards compatible with the older model transmissions (722.4/722.5/722.6). Knowing how finicky these transmissions are about the right fluid along with common knowledge about not mixing different formulas of coolant without a complete flush is keeping me from wanting to do this until if and when I get a confirmation that it is OK. Otherwise, I'll just go with the older fluid.

Trans fluid cost
 

I recently had the trans fluid changed in my '01 C320 at 44000 miles which amounted to 1/2 the fluid since the torque converter has no drain plug. The formerly "lifetime" fluid is now to be changed at 39000 miles.

I paid $14.81 per quart (or maybe liter) which included the dealer's usual above retail add-on.

I noticed an improvement in shift quality right away. The fluid used in my 5-speed auto is 001-989-21-03-10.

Roger, thanks for the reply. That part number corresponds to the original (old) fluid for the 722.6. Are you saying you had a "drain and fill" done through the pan drain plug using this fluid? I understand your car has no torque converter drain plug as well.. This would mean that much less than half the fluid was changed if that were the case.

Anyway, ~$45 for 3 liters of the old style fluid, plus you said you noticed an improvement, I guess sticking with the originall stuff wouldn't be too bad. Although, it's sooo tempting to try the new stuff if it's actually cheaper and better. Sounds too good to be true perhaps. :rolleyes:

Trans fluids
 

The fluid change in my '01 C320 included changing the filter, of course, which requires dropping the pan.

I have no idea what the "new" fluid might be since my trans had the so-called lifetime stuff in it which I thought was the latest and greatest. Perhaps the new-ish seven speed auto uses something different.

Roger,

Was this the only dealer service available for your tranny? Was there a full flush option to change out all the fluid or is this the only option of drain, new filter and top off and is this all that the dealer sez is necessary?

Thanks,

glenmore
2000 C280
1991 300CE
1990 LS400

Here's a post from benztech13:

"The 722.9 fluid will work in 722.3,.4,.5 and 722.6 cars. The cost of the fluid is somewhere around $25 per liter. That's an expensive service! I'd go with the MB 722.6 fluid."

I thought I remembered it being Liquid Gold!

The newest fluid is part number 001-989-43-03-10 aka "the 3353 fluid" and was developed for the 7-speed 722.9.

As far as cost is concerned, here's a quote from a post by M.B.DOC:

"The latest 722.6 fluid MB part number 001-989-21-03-10 has a list of $12.50

The NEWEST trans fluid for the 722.9 & 722.6 is MB part number 001-989-43-03-10 and has a list price of $7.50..."

He also added:

"dealers are using the 722.9 fluid to "help" 722.6 unusual (poor) shift qualities"

Which are two reasons that I'd like to use the new stuff, if it can be safely mixed with the old. I really don't see why it wouldn't safe, but have yet to hear for sure.

To flush or not to flush, that is......
 

<<Was this the only dealer service available for your tranny? Was there a full flush option to change out all the fluid or is this the only option of drain, new filter and top off and is this all that the dealer sez is necessary?>>

The tech offered the option of hooking the lines up to their flush machine. I declined since the cost would be substantally more than the $241 I was already paying. Plus that I intend to trade the car for a W204 early next year.

Well, I changed what fluid I could on my 2000 C280, 44m, 722.6 tranny with no drain plug on the torque converter. I changed the filter and gasket and got a total of 4 liters (IIRC the capacity is ~7.5 liters) . I used the original 722.6 fluid that I had bought a while ago. I added an extra 50ml for the new filter and the level came out spot on after warming up the car and testing with the special dipstick.

glenmore
2000 C280
1991 300CE

Flushing the torque converter by other means?
 

I do not have the car that is the subject of this thread but was wondering if it is possible to flush the torque converter by disconnecting the cooling return line to the transmission (if it has such a fitting), placing it in a suitable collection vessel and running the engine until ATF stops coming out?

I know this sounds scary, but this is the prescribed procedure to remove the fluid from Ford Taurus/Sable automatics and which I have done on my Taurus.

I don't know if the design of the Benz transmission system allows this approach.

On my Taurus, it makes a difference between getting 11 - 12 quarts out vs 4 qts by dropping the pan only.