So I have a 1986 w201 190E 2.3-16v with an auto 4 speed 722.410 factory tranny and about 105k on the car. It is in great shape and really no issues with her except the tranny problem now. It was sliding from 2 to 3 sort of slow and sluggish so I thought what better time to change the over due tranny filter and fluid and leaking tranny pan gasket. Thought it might fix the 2 to 3 slide issue if I put new filter and fluid. I used a dexron II / III trans fluid as the new fluid and I put some anti slip additive in it too. This was all after I put some flush in the trannny and drove it about 5 minutes and dumped the old fluid and flush additive. I refilled with a Dexron II / III trans fluid. It drove much much better, the slip from 2 to 3 was all but gone. THEN, two days later after maybe 20 miles max, I drove my girls to a friends house and on the way the tranny seems to have forgotten third and fourth gear even exist. It just happens in an instant while driving about 35 mph in town. Gone. So now I am hoping it is a piece of trash that broke free from the work I did. I just need to get the 3 and 4 gears working a gain. Tons of revving up but no grabbing in 3 of 4. 1st 2nd and reverse are all fine. I am hoping some crud just got busted loose while working on it. I may try to flush it all again and see if I can get what ever might be stopping the 3 and 4 gears from working and get them going again then it would all be good.
If I have to , should I buy a rebuilt from the build shop in California? The tranny and torque converter are all rebuild all ready, I just have to reinstall and adjust ( cost for rebuilt is about $2000) or do I even think about pulling the tranny apart my self, I have several manuals but no transmission internal work experience.

__________________
Christopher Henkel
1990 190E 2.6 - Arctic white SOLD
1986 190E-16v - Blauswartze
1993 300CE - SOLD
2003 W208 CLK 320 Cabriolet - Magma Red

SO I did some checking and looking and it seems one possibility is that the green vacuum modulator might need to be adjusted. It was listed as a cause of slipping in 3 and 4 gear. That would be an easy test. Any ideas on this being a possibility? I did put the upgraded K1 spring kit in the valve body when I had the pan off. Did not think any adjustments were necessary when you did that install but maybe I was wrong.

__________________
Christopher Henkel
1990 190E 2.6 - Arctic white SOLD
1986 190E-16v - Blauswartze
1993 300CE - SOLD
2003 W208 CLK 320 Cabriolet - Magma Red

The modulator will not cause the slipping, but will change when it slips..

You can test the modulator by attaching a hose on the nipple, and sucking on it your self. If oil is dribbling out of it, it shot...

K1? maybe but it should look like this forth photo on post 34

K1, K2 & B1 accumulator spring kits - Mercedes-Benz Forum

Did you take any pictures of your work? look the same?

How is first gear for you? B2 piston is a very common failure. B2 is used in 1st and 3rd. How did you get to 4th if 3rd slipped?



Martin

Here is a good troubleshooting manual.. This is good for 722.3 to 722.5

Enjoy,

Martin

Attached Files

722_3-722_5 TroubleShooting.pdf (720.1 KB, 1011 views)

Martin,
Good question. I dont think I really ever did. You are correct. I dont think the tranny every really went into 3rd so I would guess it never went to 4th. With this in mind, I guess it is more correct to think that my issue is that third gear is the issue and that 4th gear might be fine if it could pass through 3rd. That was jumping to a conclusion on my part, I was all doom and gloom at first. I need to focus on what could have gone wrong to lose lock up in third. All i did was change filter and fluid and the K1 spring kit. I used OEM MB part number A1262704477. The car drove fine for two days and about 30 or 40 miles. Then third just slipped while driving and hasnt been seen since. What could have broken in that valve body to only effect third and making it slip so much it never does in?

Attached Thumbnails

 

__________________
Christopher Henkel
1990 190E 2.6 - Arctic white SOLD
1986 190E-16v - Blauswartze
1993 300CE - SOLD
2003 W208 CLK 320 Cabriolet - Magma Red

So I opened the troubleshooting manual you attached and that is a useful article for sure. It explained each gear process individually and it said:
3rd Gear
In 3rd gear, brake band B-2 is applied and clutch K-1 is
engaged. Only the rear planetary gear set is involved in gear
reduction.
4th Gear
In 4th gear, clutch K-1 and clutch K-2 are applied. Both
planetary gear sets rotate as a locked unit.

If I understood this correctly this says that K1 is used first for third gear, which I have lost. It also says that K1 (and K2) are used in 4th, which I probably have not been able to go to since I lost the ability to connect in third gear. So if this makes sense, I am thinking that I need to focus on the K1 portion of the transmission and I changed the K1 spring set before this happened. I did note that the kit I got did not have a new piston or new piston rings (seals). I am wondering if that spring piston set in the K1 port on the valve body that I pulled and changed has something wrong with it now. That might explain the suddenness of third just going away while driving. Any thoughts?

__________________
Christopher Henkel
1990 190E 2.6 - Arctic white SOLD
1986 190E-16v - Blauswartze
1993 300CE - SOLD
2003 W208 CLK 320 Cabriolet - Magma Red

Martin,
1st gear is fine as is second. It drove great in those two gears before and even after I lost third. I can still drive it fine in 1st and second with no slip, or anything. Reverse is just fine also.

__________________
Christopher Henkel
1990 190E 2.6 - Arctic white SOLD
1986 190E-16v - Blauswartze
1993 300CE - SOLD
2003 W208 CLK 320 Cabriolet - Magma Red

Hey Buddy,

Sorry for the delay as i just moved, and I am all lost with my stuff...

B2 seal(the black seal in the bore) is known to harden-up and cause this problem if it slips from 2nd to 3rd. Here is great thread:

How to Replace Your Oil Cooler Lines

K1 has the little spring kit which goes inside a tube with two teflon split rings, and I want to say K2 is the same... Here is some links with access to the service literature on the 722.3/722.4

1996 S280 Australia transmission no reverse diagnose & rebuild. - Mercedes-Benz Forum

I'd entertain K2 and B2 as these can still be accessed without dropping the transmission..

Martin

Martin,
Talked to Marc at Sun Valley Mercedes Transmissions. When he realized that I am only sure I have lost 3rd gear lock up and all it does is slip, he thought that it was very likely that I have blown out the K1 seal on the inside of the K1 drum. That would make a certain amount of sense because K1 is first used for third gear. And the B-2 band used for third gear is also use in 2nd gear and second is fine, leaving the K1 first being used for third, which is not working.
"3rd Gear
In 3rd gear, brake band B-2 is applied and clutch K-1 is
engaged. Only the rear planetary gear set is involved in gear
reduction."
Unfortunately I would have to pull the tranny and open it up. They seem to think the seal could be replaced with standard shop tools and with a gasket overhaul kit. I am up for that. I could replace clutches and any seals and gaskets that get in the way on the trip to the K1 seal while I am in there, Any thoughts?
I am thinking I am going to drop the pan and check the K1 and B1 and maybe the K2 piston assemblies in the valve body since it is a quick check and no pulling the tranny, but it seems like the K1 seal is a good diagnosis.

__________________
Christopher Henkel
1990 190E 2.6 - Arctic white SOLD
1986 190E-16v - Blauswartze
1993 300CE - SOLD
2003 W208 CLK 320 Cabriolet - Magma Red

did you do the K1 seal? did it work?
I have a similar problem with my 722.315 no 3rd or 4th any info would be appreciated


P