This may have been answered before but...Trans question...
 

I have an 89 190e 2.6 The car was driving fine about 2 weeks ago with just a little erratic shift from 2nd to 3rd. If I let off the gas and then pushed back down, gears shifted fine and the car moved along fine. One day I came out to go to work and all of a sudden the car shuddered a little after shifting into 3rd gear but I could still floor the gas and get up and go. Now the car shifts ok from 1st to 2nd but when it goes to shift into 3rd and you are on the gas, the engine revs. It does shift into 3rd but if you are not just lightly on the gas in 3rd or 4th it'll slip. I can take the car down the highway at 80 - 90 and it'll go but only if you're light on the gas and gradually accelerate. I've been driving it like this for 2 to 3 weeks and it hasn't gotten any worse. Just out of curiosity I changed the trans filter and fluid and didn't see any metal bits in the pan at all surprisingly but the fluid did seem a little bit dark. May have just been old. It didn't make a difference, it acts the same. Wondering if it's a vaccum issue and if so what or how do I adjust it before I go looking for another trans?

What you describe is not a vacuum issue. You need tranny work.

worst case the tranny needs to come apart and have the rivets on the front sprag checked.[you have a 722.4 trans] best case it will only need clutches in the front drum and reverse clutches.the dark oil usually means that fine powdered aluminum is in it [unless trans has been neglected for long time]

As far as I know, as from what the previous owner told me, he never changed the transmission fluid or filter. Thing with this is that since this started happening like it is now, it isn't getting any worse. It's not getting any weaker like I suspected it would. I'm delivering pizza in it driving approx. 100 miles/night and have been driving it like this for the last 2 to 3 weeks with no problem. Also the car only has 96k on it.

sorry to change focus...
 

...but delivering pizza in a benz is simply awesome

I know lmao, I get some REALLY funny looks from some people ....like what the hell??? lol. Needless to say, my tips have gone down considerably :-)