I have a 1992 500SEL W140, originally had the 722.370, that one lost 3rd & 4th first, then second and finally 1st. I replaced it with a used 722.354 out of a 92 400E. Now the replacement tranny is losing 3rd and 4th. i can reach my target speed in second gear and then shift it to 4th, if there is no increase in engine speed it will stay in 4th, but if i speed up, there is no gear engagement. Is it also the k1 clutch? or the b1 band? Reverse is flawless, 1st to 2nd as well.

93merc..

It is more like K2..

Short of doing a full overhaul.

A)I would replace K2 and K1 springs. See post 13 on this thread..

B)The modulator on the drivers side(US cars) of the transmission may have something to do with it too. The modulator has an adjustment lever you play with, but i bet the seals where the modulator plugs into are shot, or the modulator is leaking oil from the vacuum fitting. The modulator in the pictures is black(it is the the device where the line on case meets up-the color is different from car to car).

C)Replace the valve seals as this whole thread is about..Post8

Martin

Attached Files

ModulatorPics.pdf (190.6 KB, 204 views)

UPDATE: I received the tranny gasket kit that was supposed to be specific to my tranny, but the seals did not match anything in the valve box, so I ended up using the originals.
While the valve box was out...
put in a K1 spring kit
the governor pressure boost valve, I moved the spring from the front to the back so the car would start off in 1st gear automatically.

My daughter (19) has been driving this car for a bit, and she is not much on using the shifter to start in 1st...shift up and back down to lock in 2nd etc. So I would like the car to drive better in "D".

What is happening now is that while in "D", starts off in 1st and goes a little too high...say around 3600 before shifting into 2nd. Then in 2nd, it drops to around 2k, and shifts to 3rd around 2.5k, it shifts too fast into 3rd leaving you gutless.

I need to lower the 1st shift down to under 3k, and move the 2nd up to around 3k.

This car has 208k miles on it...the engine is tired and needs a bit higher rpm range for proper acceleration.

Thanks!

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1990 300TE....all comments are about this car...in case I forget in the actual post

Forgot about your thread,

But I feel bad for recommending the kit. On mine everything fit..

Sounds like you are having leakage on first gear valve.

Martin

Tomorrow, I am going to drop the valve box once again, and restore the shifting to the way it was before. After, I will play with that cable that runs under the air cleaner, and maybe adjust that pressure screw...see what happens.

As you can see, I have my terminology down pat!

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1990 300TE....all comments are about this car...in case I forget in the actual post

My only 2cents is you have disturbed the main paper gasket of the valve body to the bottom of the transmission.

Move the bowden cable only 2 to 3 turns, and then drive the car.. If you screw in the cable the shifts slip in early, backing it out cases it to shift late.

Martin

Going out there in about an hour to do the deed.

Question...my biggest issue has always been that the tranny does not stay in 2nd very long before shifting into 3rd. Will the bowden correct this issue, or is there something I need to do with the pan down?

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1990 300TE....all comments are about this car...in case I forget in the actual post

No, Bowden will not fix this.

It can be many issues. The worn B1 and B2, The seals to those pistons. The play of the thrust pins to the brake-band B1 and B2.. Worn valve body ports that drive B1 and B2..Leakage in the seals near the brake band 1.

It can be a lot...Be happy you got 200kmiles because mine failed at 130k miles..

Martin

The car always did this. I have two of this exact same make and model, they both have always done it. About 10 years ago, I researched the "why" of it. From what I read, it was an epa thing...just like having the car stay in low gear until it warmed up a bit...they wanted to get the car into high gear as quickly as possible. I dont know.

That was when I read about doing the shift trick so you can start in 1st...when it shifts into 2nd, immediately move the shifter back down to lock it in..etc.

Just figured the word was out on how to undo what seems to have been deliberate.

Unless, of course, non of this related...lol

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1990 300TE....all comments are about this car...in case I forget in the actual post

SUCCESS!!!!! Put this baby toooooooo bed!

I timed the procedure. From the time I started collecting the necessary tools, to coming back inside to sit down and pat myself on the back, 2.5 hours.

I yanked out the valve box again, split the box, changed the Governor Pressure Boost Valve spring back to its original position...in FRONT of the governor, put it all back together...then test drove for about 15 minutes dialing in the Bowden Cable....

This tranny now shifts better than it ever has. Yes, there is still that too quick a shift from 2nd to 3rd, but now it is happening at about 500 rpms higher, which feels much more comfortable in the existing power band of the car.

Not only is my tranny working normal again after losing 3rd and 4th, but now it shifts better overall.

Happy Camper!

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1990 300TE....all comments are about this car...in case I forget in the actual post

Hey, good for you. Success is great..

My 96 S320 with a 722.5 does the same thing it feels like slips from 2nd to 3rd. For now I have other flea's to deal with. I will deal with 2nd gear later.

Best of luck, and toy with the cable when the car is hot and cold...

Martin