'99 E430 722.6 Clunky 2-3 shift - PeachParts Mercedes-Benz Forum

Hirnbeiss · #1 10-27-2006, 07:44 PM

I changed the tranny fluid (and filter) last weekend with 8 liters of Dr. Z's secret profit formula. The old fluid was dark, as expected, but there was nothing unusual in the pan - not bad for 95K.

Now I notice that the up- or downshift from second to third is clunky, and the downshift to second causes a noticeable drop in RPM when slowing to a stop, as if this might eventually cause a stalling problem. Maybe it's staying in third too long, and then finally clunking hard into second when it realizes it better move along.

Any alternatives to visiting one of Dr. Z's US henchmen, who will automatically overcharge me as step 1 of their diagnostic procedure?

Thanks,
Tom

deltajetfixer · #2 10-27-2006, 09:06 PM

Quote:

Originally Posted by Hirnbeiss

I changed the tranny fluid (and filter) last weekend with 8 liters of Dr. Z's secret profit formula. The old fluid was dark, as expected, but there was nothing unusual in the pan - not bad for 95K.

Now I notice that the up- or downshift from second to third is clunky, and the downshift to second causes a noticeable drop in RPM when slowing to a stop, as if this might eventually cause a stalling problem. Maybe it's staying in third too long, and then finally clunking hard into second when it realizes it better move along.

Any alternatives to visiting one of Dr. Z's US henchmen, who will automatically overcharge me as step 1 of their diagnostic procedure?

Thanks,
Tom

With the engine and transmission at full operating temperature, you could try filling the transmission all the way to, but not past the full 80 degree mark on the dipstick.

When I replaced mine with the new 722.9 fluid I did this and noticed an improvement in shift quality.

TMAllison · #3 10-27-2006, 10:04 PM

I think that it is difficult to get every drop of fluid out even if left draining overnight. The factory fill is 8L. You mention putting in 8L but don't state you checked the level with the factory dip stick tool. I think most DIY have put in something less than 8L generally.

The fill level and measurement temp are critical, are you certain it is not overfilled?

Hirnbeiss · #4 10-28-2006, 08:32 AM

But I would also say that there was no difference in shift quality from when the fluid was at the low end of the dipstick.

But you do raise a good point. My trannie is the 722.623 (behemoth) for the 430. The owners manual actually lists over 9 Liters as the ATF capacity, but the Alldata site lists 8.2L.

TMAllison · #5 10-28-2006, 11:24 AM

Mine (also a 99) is listed as a 722.608. My manual lists 8L.

Perhaps your 722.623 is underfilled if the correct fill is 9L?

I think most poeple put back a few hundred ML less than a factory fill as the valve body will hold some fluid.

The key is the knowing the temp of the fluid when checked and the dip stick tool.

Hirnbeiss · #6 11-10-2006, 05:21 AM

Overconfident though I was that I had filled the fluid to the rim with Dr Z's snake oil, I checked the level again several days later and, indeed, there was room for more. Eager, as I was, to line the DaimlerKreißler pockets with yet more of my hard-earned cash, I bought another liter of of Sindelfingen Syrup and poured about half in. I am pleased to report that, contrary to all reason and common sense, the extra half-liter seems to half done the trick, as I have now been driving nearly two weeks enjoying once again the silky-smooth shifting that 722.6 owners have come to intermittently experience.

In hindsight, this makes perfect sense: the DCX profit control unit wouldn't send an "OK" signal until it had calculated that I had bought enough genuine MB oil.

In any case, it may take another level reading later to give a accurate indication. My total refill was 8.5 Liters, while I drained only about 7.2 out.

blackmercedes · #7 11-10-2006, 10:14 AM

Is the fluid temp set to 80C while you're checkign the level? Not the engine coolant temp, but the actual trans fluid? It's level can change dramatically with the change in temp. The dipstick tool is meant to measure the fluid at 80C. It's easy to do with the SDS.

firstbenz · #8 11-10-2006, 12:52 PM

Deltajet,

I have a e320 with the 722.6 is it ok to use the newer atf in our transmission?

Blackmercedes how do I know I have the atf at the right temp? Just check it after I run the car?

Thanks for any info I plan on changing the fluid and filter myself on my e320 and any info on the subject will be great before I dive head first into it.

blackmercedes · #9 11-10-2006, 05:08 PM

The "new" 722.9-style fluid is recommmended for the 722.6 trans. You use the SDS (Star Diagnostic System) to read the fluid temp directly, and set the level once the 80C mark is met. It's not too tricky, but works best with two people. However, I just pay to have it done...

Most good indie MB shops have the SDS (otherwise dealers will hose you for the labour) and I don't bother doing the trans fluid change myself as the 722.6 is pretty picky about the fluid level. The hour's labour my mechanic charged me was more than worth having it done right. Also, with the SDS hooked up, you can read the trans adaptation values and see what's going on inside the trans with regards to shifting.

There are many DIY'ers that have done this job without problems, but I have seen quite a few trash their tranny. At $2500, the 722.6 is too expensive for me to take a chance on.