no reverse / jerks in reverse when cold

61981 Views 30 Replies 8 Participants Last post by LAZARDIO, Dec 12, 2008

datpet07

Discussion Starter · Nov 11, 2008

2

1994 Mercedes Benz S 320 SWB (140.032) L6-3.2L (104.994) (transmission—722.5) When I got this car it had no reverse and still doesn’t have. When the car is cold it jerks back but after it warms up it doesn’t even jerk. I was told that solenoid/actuator has to be changed but I want to hear your guys opinion. What I have done so far is took the oil pan off and valve assembly. After doing some research I found out that it is missing a Range Selector Valve. Is that a possibility?

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jhodg5ck

· #2 · Nov 12, 2008

clutches are likley toast..or reverse seal is torn..VERY common..

Have to drop the trans and rebuild..

How many miles on the trans? Material in the pan?

Jonathan

datpet07

Discussion Starter · #3 · Nov 12, 2008

Well i took the pan off and there was no material and the fluid was clean. miles=105000. thanks

BENZBOSS

· #4 · Nov 13, 2008

http://w126.pp.ru/akp722.pdf

datpet07

Discussion Starter · #5 · Nov 13, 2008

Where is the reverse seal located. Pictures would help. thanks

jhodg5ck

· #6 · Nov 13, 2008

In the middle of the trans...you'll need to disassemble just about the whole thing to get to it.. In which case you might as well rebuild the entire box.

Jonathan

datpet07

Discussion Starter · #7 · Nov 13, 2008

So it cant be the solenoids? right.

jhodg5ck

· #8 · Nov 13, 2008

Not on your .5...no electronic controls.

Jonathan

MAVA

· #9 · Nov 14, 2008

About reverse, Jonathan is correct on what he is saying, and you could also have another problem. As you go into reverse(when it goes into reverse), a clicking sound may be apparent. This is the result of worn clutches hitting the B3 reverse clutch assembly.

The problems you are experiencing are the same ones I currently have, and I also have the B3 damaged. I currently still drive my S320, and I just do not park where I need to use reverse, yet I'm lucky I do not live in a populated city, parking is very abundant(I park where I drive-off in the forward direction) where I live. I've had this problem for about five months, and I still the drive the car. I also done two 1000 mile trips in this condition. I will service the transmission my self early next year. My car has 722.508 transmission, and this transmission is all hydraulic except for the overdrive gear it is controlled by a solenoid.

Martin

dbmoylan

· #10 · Nov 14, 2008

Very common problem on our 722.5 transmissions. Had mine removed & rebuilt. Benz has upgrade parts that you should seek out w/ a competent shop that knows this trans. I doubt changing/rebuilding the valve body will help the reverse failure much, or just temporary fix. I recommend having it opened up & rebuilt w/ new parts that are likely worn out.

jhodg5ck

· #11 · Nov 14, 2008

MAVA said:
About reverse, Jonathan is correct on what he is saying, and you could also have another problem. As you go into reverse(when it goes into reverse), a clicking sound may be apparent. This is the result of worn clutches hitting the B3 reverse clutch assembly.

The problems you are experiencing are the same ones I currently have, and I also have the B3 damaged. I currently still drive my S320, and I just do not park where I need to use reverse, yet I'm lucky I do not live in a populated city, parking is very abundant(I park where I drive-off in the forward direction) where I live. I've had this problem for about five months, and I still the drive the car. I also done two 1000 mile trips in this condition. I will service the transmission my self early next year. My car has 722.508 transmission, and this transmission is all hydraulic except for the overdrive gear it is controlled by a solenoid.

Martin

Yes, that was my original diagnosis..either torn seal or worn clutches;-) Also, when the clutches are worn badly enough the reverse piston can extend to far as to come out of it's housing thus eliminating any attempt @ engagement.

Sadly, the .3/4/5's all suffer reverse issues..the .5 has the added problem of an underlubriacted OD which when that lets go typically takes the rest of the transmission with it..:-(

Jonathan

bayhas

· #12 · Nov 16, 2008

there are 2 electrical selinoids in the 722.5, I had to replace one to control the 4-5th shift. when that one was blown, I lost my 5th.

bayhas

· #13 · Nov 16, 2008

and regarding the reverse in 722.5, there is a service bulliten about it. if I remember correctly, 3 possible causes, none needs tranny drop...

I ll look it up and let you know...

bayhas

· #14 · Nov 16, 2008

bayhas said:
and regarding the reverse in 722.5, there is a service bulliten about it. if I remember correctly, 3 possible causes, none needs tranny drop...

I ll look it up and let you know...

It is on my server and I didnt realize it...

http://www.bayhas.com/w140manu/service/7225.pdf

datpet07

Discussion Starter · #15 · Nov 18, 2008

3

Ok, guys finally i cracked open my transmission and found that the seal is broken in the reverse piston.

Please tell me if this would be the problem. thanks

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jhodg5ck

· #16 · Nov 18, 2008

Yup..thats her... Might as well feed a new set of clutches and fresh band in while you are there..

Jonathan

datpet07

Discussion Starter · #17 · Nov 18, 2008

Well i think that my clutches are still in good condition.

How can i check?

jhodg5ck

· #18 · Nov 18, 2008

Doubt it...And why go that far only to put the used clutches back in??? If Nothing else replace the reverse clutches...I've seen them go paper thin in a matter of 50K.

visial inspection...but I suppose knowing what a new one looks like helps

Who's manual are you using for this rebuild?

When ever I go into a trans for this sort of thing everything gets done...I hate 2x work.

Jonathan

datpet07

Discussion Starter · #19 · Nov 19, 2008 (Edited)

3

Somebody replied to my thread and gave me a link for a manual, but if you have better manuals and how to put the transmission (722.5) back i would appreciate it.

What is a good clutches width?

thanks

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datpet07

Discussion Starter · #20 · Nov 19, 2008

Does any body have a good manual for mercedes s320 1994 transmission (722.508) thanks

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