downhome

Greetings, 1993 w250 diesel. I have an automatic transmission, 518 I believe? It has an auxiliary cooler, plus the factory cooler, and the fluid level is difficult to gauge as it is never hot. I was wondering what happens when an automatic is overfilled? How bad is it for it, etc.

Thanks, use this site a ton. Been doing searches for the last hour, nothing on overfilling an automatic. Happy Thanksgiving as well.

ofcmarc

Aim for the lower end of the hatch marks on the stick if you aren't getting it all the way to operating temp.

downhome

Thanks for the reply. I see a transmission draining being done in my future....

downhome

... anyone know how bad it is for an auto trans to be overfilled and ran?

Boatnik

I accidentally overfilled mine on Sunday afternoon. To keep from draining or in my case to keep from dropping the pan I took an old fashion suction pump and attached a hose to it the same length as the lower hash mark on the dip stick. When the pump lost suction I was at the right level.

downhome

That's genius. Got a drain plug on mine to try.

Boatnik

GEEZ you just can't hide money

dieseldawg604

overfilling a automatic tranny is a big no no!!
iv heard of a new built 518 fried after only 1000 km from being overfilled by only a quart!!

downhome

snort, yap, I've got tons of no money. Maybe I could sell that fancy drain plug.

Thanks for the replies. I will be draining tomorrow as it is overfull now. Guess I'll drain about a quart and run it, then check, drain again if needed, etc.

This has been somewhat of a headache trying to figure the level out. The thing never gets hot enough, so I'll be aiming at the bottom of the hash marks for warm as said. Like I don't have enough to worry about, now I'm frying my transmission.

THEBIGBULLY

Awesome.....I'm a genius too!!!!!!

jughead

built autos for almost 40 years. i have NEVER seen any auto come apart from over filling. couple of quarts overfull will not hurt a dodge rear wheel drive trans. i have run some gm front wheel drive trans 1 full gallon over full and they ran for years. they darn sure will come apart if 2-3 quarts low. i know this disagrees with the book guys so flame suit on

ChrisLib

make sure you cycle the shifter to neutral just before you ck the level to make sure the converter is full, esp if the truck has sat for any length of time (couple hours or more).

ClassA4x4

I agree, I overfilled (semi-intentionally) my dry 47RH. I wanted to make sure the fluid gets to every part of the tranny. I drove it for a total of about 40 miles (unintentionally), then I had to drain almost 2 quarts to put it at proper level. It didn't even puke any fluid at the overflow tube. The trans is still intact and still turning like silk.

BC847

It's my understanding that overfilling a trans can cause excessive foaming of the fluid which can lead to goofy hydraulic pressures causing burnt clutches. Never mind weeping seals.

jughead

guys and gals just remember one thing. the book on automobiles is not carved in stone. some of us have tried a lot of stuff different from the book. a lot of it worked and a lot of it didnt work. do what works for u. a few times i went head to head with the factory reps. sometimes they proved me wrong sometimes they didnt.