I don't drive my '86 E350 with 6.9 much, but lately when I start it and put it in gear, I have nothing. When I'll rev it the transmission "slips" in gear. I've check the fluid level and have "topped" it but still has the same symtoms. After it's warm, the transmission works great for the rest of the day.
Is it time for a rebuild or can I get by with an adjustment?

 

check your service manual.

speaking of adjustments it would not hurt to make sure the band is adjusted and the vacuum modulator is not leaking and sucking tranny fluid instead of actuating the valve body.

 

I'm not good at oil drive but is the converter a part of the problem also if the oil has leaked out of it? I dunno.

 

The convertor is constantly pressurized by the oil pump so even if the seal is leaking pretty badly the transmission will still work fine, until too much oil leaks out.

Birken

 

Could be something sticking in the valve body perhaps. If not, it's probably time to pull it out.