transmission won't shift...
 

I have a 1990 300E, the car works fine when it is cold. Once the car gets warm it will not shift from 3rd to 4th. Transmission fluids and modular valve has been changed. It ran better for a few days when fluids and valve was changed but it has started doing it again. Does anyone know what could be causing this or what I can do to fix this?

^^bump^^

I had similar problems about a year ago. Try changing the transmission filter. Usually that's the problem (gets plugged. If that does not solve your problems, you have no choice put to rebuild / replace the transmission. Your car is 15yrs old...the transmission is expected to fail at some point. Get it replaced with OEM equipment and your car will run good for another 15years.

GL.

same thing happened to my car a couple of years ago. clutch pack on 4th was gone, and 3rd was on its way out. I was driving the car and all of a sudden it just wouldn;t shift into 4th gear. then it started flaring on 2-3 shift. Drove it to my mechanic, he dropped the pan right there, and there was the clutch material in the pan.

Had to have it rebuilt.

AshMan

How much is a normal transmission rebuilt/repair anyways?

i would say anthing between $1200 and $1600 depends on the tranny damage

Concur on this one, I had to change the fluid and filter TWICE before the unit started shifting correctly again.

I agree w/AndreNY's price range. I dont' remember exactly, but it was around $1,500-1,700 to rebuild my original transmission with OEM parts. Pretty decent price considering it included labor. I'm hoping it'll last another 19yrs.

I was going to just get a rebuilt one from the mercedes dealers, but they wanted something like $4,000 up front w/your core (They give you a rebuilt one they already have in stock). They send your core somewhere to have it inspected. If your core can be rebuilt, you get back $2,000. Otherwise they kept the full $4,000. Keep in mind this was just for the part alone. Labor is additional $$$$.

Don't go with aftermarket parts in your transmission, you'll regret it later. Use OEM parts and do it right the first time to avoid any headaches.