Dealer says don't use synthetic in tranny.
 

I'm about to service my '90 300 CE transmission and called the local MB Dealer to check on price. When I mentioned the cost for synthetic, the service advisor was adament about not using synthetic in my car. He stated that they only recommended it for late model MB's, I didn't get the specific years. My transmission currently has synthetic (from former owner). Which direction do I go? I'm going to change the TC fluid also.

My local dealer did recommend (and install) Mobil1 in my 85 300CD's transmission.

He's talking about the specific MB synthetic tranny fluid for the 722.6 five speed boxes. He's right about that, as you shouldn't use it in the older trannies.

As to products like Mobil 1 that are designed for the older units, it should be fine. Lots of people on this forum have used those products with success...

I have used synthetic trans oil (Mobil 1) in all my cars and have been extremely pleased.

I'm curious, on the Mobil1 ATF, do they specifically state that it can be used in place of different types of recommended ATF, in MB's case, MerconIII/Dexron?
Are there specific "types" of Mobil1 ATF, for example is there a MerconIII Mobil1 ATF, etc? Different types of ATF have different slip qualities, I'd be leery of using a "1 type fits all" ATF.
Gilly

Here is the Mobil1 ATF spec sheet

Thanks for the info. Looks like it's good to use in all MB trannies except the 722.6.
Gilly

Gilly sorry for my ignorance, which model is the 722.6 in?

Per the MB "Factory Approved Products Service", Mobil ATF be it conventional or synthetic IS NOT listed as an approved ATF. With that said, I have it in my TD's tranny, but I did that before I got the list from Mercedes. When I read the list, it definetly raised an eyebrow with me. I was VERY surprised to not see Mobil/Mobil 1 listed. As a matter of fact, no synthetic ATF is listed.

Right, they just want the "regular" DexronIII/Mercon used. Since MB thinks so highly of Mobil1 (re: the stickers in the underhood area of the newer cars and the "Mutual Respect" ads in the auto magazines), they probably "would" recommend it, but don't want to go through the testing process on cars which are 5 years old, minimum. Believe it or not, all the brands of fluids they list have gone through a qualification process by Mercedes-Benz to be on the approved products list, same with the recommended tires. Just because a product is not on the list doesn't neccesarily mean it's no good, it may just have never been tested.

Someone can help me out here, but I believe the first year of the 722.6 (electronically controlled transmission) was 96, but only in the top line cars, like the s and SL, and was introduced to the other car lines gradually. I believe in 98 they all had it. The 722.6 cars all have the "S W" switch on the shifter, that's the easiest way to tell, and MB sells a fluid just for that trans.
Gilly

The SL300/320 had the 722.6 quite early, something like 92 or 93 I believe. The S320 had it in 95 I'm fairly sure. 1997 was the model year where every car got it.

Is this the five speed auto?

Is there a chance my Tranny had it? 93" 400SEL

I'd stick with my original timeline of 96 being the first year, but only certain models. The SL320 and S320 they developed the 722.5 5 spd overdrive just for those models, until as I stated, 96 is when they went from the .5 to .6 on these models, including the V8 and V12. I can hopefully get a good timeline for when the different models went to the 722.6.
You can definitely tell if your car has the 722.6 if it was the rocker switch on the shifter plate, one side marked "W", one side marked "S", W is for winter, which gives a second gear start and a different reverse gear ratio, and "S" is "Standard", which gives a first gear start. Also a 722.6 has a very distinctive type of dipstick tube cap, which has a one-time use locking tab, and there is also no dipstick on the .6, just the cap.
Gilly

Found the 722.6 introduction timeline
 

OK, here's the info on when the 722.6 was introduced:
*from 03/95 in the C140 with engine M120 (S600 Coupe)
*from 09/95 in the W/V 140 with engines M119 and M120 (S500 and S600 sedans, long and short wheelbase)
*from 09/95 in the R129 with engines M119 and M120 (SL500 and SL600)
*from 01/96 in the W210 with engine M119 (E420)
*from 08/96 for all MB passenger cars with 4,5, or 6 cylinder engines.
Gilly