I just bought a 84 190e and it is my first benz, it runs great but the trans does not like to shift until it almost hits the redline on the tachometer. It sounds like the vacum modulater to me, what do you guys think?

 

the vacuum modulator only increases and decreases the shifting pattern according to shifting pressure, almost similar to the governor which opens and closes the valve according to speed.
it is adjustable if you will pry out that black cap and you can rotate the "key" like thing on it. be carefull if you don't have the pressure gauge attached, remember the original position.

first tell me what gear is it that's hard to shift? 1st, 2nd, or 3rd? play with the shift lever to find out, but don't overun the rpm to protect the engine on low gear. max 4000rpm.

 

It revs high in every gear, it does not slip at all. It always shifts at 5500 rpm and when it does shift, its shifts hard. The fluid was clean but I changed it anyway. It does not downshift well at all either(it waits till the last minute to downshift)

 

you are halfway right in suspecting the modulating pressure. but before you touch that one, please check that the control pressure cable is set on the basic position and no other things affects it. it is the cable that is actuated together with accelator linkage. make those two arrows aligned and re-check the function.

when you change the ATF, was it whitish in color? sometimes the coolant can enter through the oil cooler.

have you replace the frition (clutch discs) lining on this transmission already? running it this way will only affect other linings (you can tell by the burnt smell on the ATF.

other things that might cause your problem is the governor pressure as i have mentioned earlier. you really need a pressure gauge to check it, or else all you can do is to clean the centrifugal governor and make sure it is free of movement. this one is easy to remove with the car lifted. please make it very safe when you go under the car. put lots of blocks or jack stand. don't take any risk...!

your last resort is the pressure regulating valve. check it for freedom of movement too. in this one, you need to remove the oil pan and it's on the valve body.
easy to find. it's on the same side as the selector valve (the one that moves everytime you shift mechanically, attached to the external shifting lever). the regulating valve is the one protruding (sorry about my term) on the rear end which is locked in place by the hold-down plate(got 8 screws i guess).
pull the valve body out to do this job, it's easy. if you split it open, just remember the position of non-return reed valve and particle screen. you got valve ***** there too. make a diagram drawing to remember the locations.

enjoy!!!

 

The fluid was great shape, the right color and not burn't. I am going to adjust the cable in the morning and see if that makes a difference. Do i want to loosen it more to bring the shift RPM's down? or is it the other way around
Thanks for you patience
Andy

 

tightening it (means screwing out the adjuster to lenthen the outer cable and shorten the inner one) advance in shifting. because this thing goes directly to that REGULATING VALVE i mentioned. you see, we are talking of common function of only different location.
i am very familiar with these transmissions in my earlier days (thanks to my teacher gerhard schultz) that doing it is relatively easy. i wish i was in your area to assist you... for a bottle of beer.

was your transmission a 722.3 or 722.4? you can read this from the housing just above the oil pan. i can give you the technical adjust data such as modulating pressure. it is in bar, so you can use any gauge to get the perfect reading.

anyway, did you pull out that modulating box before? there is a plastic plunger inside that easily gets broken!!! you can check it. if you pull it out, make sure that you go in a very straight line going out.

since your oil got no burnt smell (we are talking of the old oil), the problem can be corrected by yourself with less difficulty.

if you open that oil pan, please see if there are foreign bodies on it, especially those shiny steel bits.

 

I adjusted the cable and it works great now, Thanks for you help
Andy