W126

Hey- I am new so please forgive any faux pas-After fueling up, suddenly would not upshift, but if moved to neutral after reaching shift point or higher rpm would slip into higher gears upon shifting back into D- your manuals on this subject seem to only cover diesels up to 1985- can you direct me to appropriate manual/technique/parts/etc I am guessing vacuum trouble but know nothing more on subject- thus I would also like a primer on the vacuum system in general-Thanks!

I am putting in my new balanced injectors and injection pump stub shaft o-rings. I took off the crossover pipe to gain access to the third injector and just give me more room to put hard lines back in after cleaning them off course. I found that there is an oily gunk in the cross over pipe and the intake should I be worried about my turbo? I do have a small oil leak from the turbo (the only oil leak on the car) are the doughnuts bad turbo getting bad ect. Should I take the intake off and clean it and get a new intake gasket soon?