Engine on or off to check auto trans fluid level

[Robert K]

I changed the automatic transmission fluid in my 1991 535i today. I don't have my Bentley manual with me (visiting my parents) and the owner's manual doesn't even mention checking, let alone changing, the trans fluid. I measured what I took out and put just a bit less back in. Now I need to add until I get the level right. Am I remembering correctly that I need to have the engine on and warm to check the trans fluid level? I also think you're supposed to move the selector through all the gears to make certain the trans valve body is filled. Does this all sound correct?

Grace and peace,

Robert K
1991 535i

[Javier]

nt

[George M]

yup as Javier says. The 4 HP 22 EH is very sensitive to fluid level. You really want to get it just right. Javier says don't overfill...but you sure don't want to underfill either which will cause the trans pump to cavitate. The fluid expands a lot as the trans heats...so definitely check it fully hot and not warm as your fluid level will vary by quite a bit depending on temp.
HTH,
George