rayray76

I have read 100 posts on this topic and for every person that says flush there is a person that says drain and fill..
Maybe I can get a good answer for MY scenario as i understand not all cars are equall

My 95 sc400 has 177k miles on it.. right now it runs good but the tranny oil is a l more brown than red... This tells me that the oil has been in there for probably 50k miles.... also the guy that did it overfilled it by about a quart cause the level is 1 inch above the mark. So far I dont think that has done any damage as i said car shifts pretty good...Now... Can someone steer me in the right direction.. I know i have to get the brown fluid out but what is the safest way to do it..I have an appointment at mechanic shop on monday to do a flush but I would likek some input on whether you guys think this would be a good idea..??flush and get tranny completely cleaned out.. or do a drain and fill once a month till its all red???
As always this noob appreciates all the help he can get..

Tammy

Insure your checking the fluid level with the engine running, or it will read about an inch overfilled.

177k dictates you should drain and fill several times, instead of a power flush.
Once a month till red is what is recommended.

The flush has a tendency to stir up small particles that foul the small ports within the valve body.

HarrierAWD

Agree with Tammy. Drain-n-fill is the way to go.

Flush only when someone put the wrong fluid in there.

miltonlin

In your situation, I would do the drain and fill. I think even the people who believe in flushing would not recommend you to do so given the condition of the vehicle (current mileage and time between last service).

I'm not as much as a DIY as Tammy and others on this board, otherwise I would do my own drain/fills.

Lexmex

I agree, drain and fill in your case.

About the only time that I have done a flush is when the fluid is silvery/pinkish, which means it has some of the bits of the transmission in the fluid. It can happen, and it did once several years ago in mine, but a flush really made it much better.

In your case, drain and fill, sometimes a flush can shock the system if it is done a great while since the last drain and fill and/or flush.

Pheonix

Flsuh it. There's no reason not too but lazyness, and no substitution for it. Using a machine to do it is copping out. Learn to do it the correct way using the cooler passages.

Over-filling a transmission is not some death nail to the transmission like under-filling. Just like overfilling an engine within reason isn't going to destroy an engine. You have a problem with overfilling a transmission when:

• It begins to leak, which in itself is no caused by over-filling. The leak was already present
• The actual problem is air being whipped into the pick-up tube. If you pull the dipstick, or drain hot ATF & it's not frothy with air in it. You didn't over-fill it to the point of having a problem.

There-hence-forth. If it's not frothy no harm - no foul.


Personally... I've settled into flushing here & there, but doing pan dran & fills with oil changes. Like I said. There is no substitution for flushing.


Also, I'll admit I went along with the (only changing 30% of the fluid) bit for along while. And I was wrong, seeing that if you read the transmission manuals, you see that the majority of them change 60% of the fluid if you let the pan completely drain (i.e. fluid out of the valve body.) Which itself is not going to happen without really dropping the valve body.



At any rate...
Flush it first. Drain the pan for maintenance. Then repeate.