no fourth gear
 

Hi All
I recently purchased an 85 300D california model with 128 k, the car runs nicely, has a few bugs, but is responding to TLC, with the exception of the transmission, the oil was slightly discolored ( brown ) so I changed the fluid and filter, also engine oil and filter, differential oil and brake fluid, anyway about 50 miles after the oil and filter change it quit going into fourth gear, no warning just quit, the oil still looks new, is there anyway for this to be a valve body problem or do I need to plan a rebuild? any suggestions will be appreciated
Thank You

No 4th gear can be, burnt / leaking K2 clutches or drum, a leak in the B2 inner seal and valve body related.

Checks the fluid level, make sure the transmission is full. Read both sides of the dip stick, the lower reading is the true level.

If you had 4th before the transmission service I am thinking a stuck valve in the valve body, a transmission flush may fix the problem. Good luck.