Still battling this shifting matter...
 

1996 E320 with 722.329 transmission. The original transmission completely bit the dust shortly after we bought the car so I purchased a used unit from a lower mileage crash victim. After the swap, the replacement transmission hasn't wanted to upshift until at least 3,000-3,500 rpm. I have taken the following steps to troubleshoot this issue:

1. Adjusted the bowden cable and even disconnected it completely at one point. - No change, still wouldn't shift.

2. Checked the kickdown solenoid and disconnected it also. - Still no change, won't shift.

3. Discovered and corrected a vacuum leak - Still no change, won't shift.

4. Checked the working pressure and modulation pressure. Both were in spec. I'm going to check the governor pressure tomorrow.

5. Removed and rebuilt the valve body from the other transmission and swapped them out. - Still no change, won't shift.

I suppose my next step is to remove and inspect the centrifugal governor assembly. That is on tomorrow's agenda also.

Question: I have read that the governor assembly is serviceable while the transmission is still in the vehicle. From what I experienced while replacing the transmission, it is VERY tight up in there. Is there some special technique to remove it that will make things easier for me?

Any and all suggestions are greatly appreciated! :)

Christine

christine,take out the valve body and the separator plate above it.there is a small valve body attatched to the separator plate by 4 slotted screws through a strange shape flat metal plate.take out those screws and it will release the small valve body.now,look closely at the side of that valve body and you will see two very small filters pushed into round holes.use a pick to lift them out and probably one of them will contain a lot of crud.the fluid to the govenor goes through that filter.that may be your smoking gun. ps when you put all this back together,before you tighten up the slotted screws,put most of the screws through the holes to line it all up or you will have hell replacing the valve body on the spacer plate.

Thank you for the reply David.

Just thinking ahead, wouldn't the governor pressure reflect a low reading if those little filters are clogged also?

Update: Scratch that last question. I just went out to move the car into the garage to work on it and it won't even move now. No forward or reverse gears. Looks as if the valve body has to come back out anyhow. :(

Before I tear this thing apart AGAIN, can anyone tell me which part in the valve body could cause me to lose all forward and reverse gears? I had both of them yesterday, but last night it lost both in the driveway. I can only presume that something got stuck. :confused:

Christine

Okay, I pulled it back apart and checked the screens that you mentioned David. They appeared to be pretty clean, but I went ahead and washed them along with the little valve body piece and the intermediate plate. Everything is spic and span clean. I'm heading out to the parts store right after the Miami game to buy more ATF. I'll report the results afterward.

Update: Not knowing what the problem might have been with the other valve body, I put the original back in. I have forward (2nd) and reverse gears back now, but it won't upshift at all. :( I'm getting a little frustrated at this point. Any ideas on what my next plan of attack should be?... Anyone? :confused:

I managed to get the governor assembly out this afternoon. Boy that was a tight squeeze! I had to drop the rear of the transmission and wedge it over to the side with a block of wood in order to provide enough space to remove it. It doesn't look dirty, but who knows? I'll wash it down really good and make sure that it moves freely before I put it back in. Is there anything thing else that I should do to it or the transmission while I have it out?

All I know is I am not worthy...wow!

Newbie question. Do these transmission use steel or vulcanized rubber check balls? On the Ford 4-speed with OD they used rubber. Which is fine. However, standard trans fluid deteriorates them so Ford issued a TSB to use Merc V synthetic blend.

Anyway. If vulcanized, I would replace them with new since a reduction in diameter can cause all sorts of issues. Also, in my case, one was shrunk down so much it was wedged into the separator plate! Oddly, it caused no issues. Found it when doing a performance mod.

Christine,

In my 300E, it engages Drive and Reverse a little harshly (jumps). Then it is fine shifting and driving (186k on it), etc. I am told this is a worn brake band/piston engagement issue. Do you know with your expertise if I can repalce these parts on this transmission in the car but dropped down or do I need to take the whole thing out to do it? I can't seem to find anyone brave enough to just try the part replacement for me even though I'm willing to pay and i don't have the tranny jack to do myself :) Sorry to interupt your thread. You can email me at sptt144@aol.com if you have an idea about this.

Thanks,

Steve

The Mercedes shop manual I have for this transmission essentially says not to bother with checking the vacuum modulator for harsh engagement like you describe. That only leaves high line pressure as the cause. This can be due either to high idle speed or something in the valve body causing line pressure to be too high.

The band problem you refer to is probably the B2 piston failure, but this causes no forward engagement because B2 or K2 have to be applied to get any torque through the rear gearset (except in reverse, there is a one-way clutch there that applies due to reverse input to the rear gearset) Reverse is unaffected in this case since the only apply component involved in reverse is the reverse clutch. Now, those are also known to go bad usually causing delayed engagement in reverse only.

Steve,

I am a far cry from an expert, but here is what my manual states regarding your transmission's symptoms:

HARSH ENGAGEMENT WHEN SELECTING "D" OR "R":

Idle speed too high. Check pressure receiving (pick-up)
piston in valve body for ease of operation and correct installation.
Replace valve body (if necessary).

NOTE: Pressure pick-up requires a running period of approximately
2 seconds. Harsh engagement may occur during repeated shifts
between "N" and "D". If harshness takes place within 2
seconds, condition is considered normal.


Hope this helps.:)

Christine

LandYaghtLover,

Indeed, the 722.3 trans does employ 18 vulcanized rubber check balls. However, I checked the diameter of them with a vernier caliper and they were all within .01" of spec.

Christine

christine,with all that youv'e been thru i would suggest having someone good rebuild your valve body or go to web site fixeuro.com [they are in dallas and are friends of mine]they may have a valve body already built that they can exchange for you or rebuild yours.

David,
If the governor assembly doesn't end up being the culprit I may do exactly that. Although I'm a little frustrated with it, I'm extremely determined to figure out what the problem is. It's the principle of the matter at this point. :)

Thanks for your help.

Christine

Thanks Christine. I think it just may be too high of an idle speed. It idles out of gear at about 700-750 rpm and in gear about 550-600 but it is smooth. Good luck with your transmission!!! I like a determined person who wants to figure it out on their own! I don't know how to mess with or check the pressure receiving pick up piston :)

Steve