Am I asking for trouble? 300sd Trany fluid change. - PeachParts Mercedes-Benz Forum

tr1cky · #1 12-10-2009, 04:27 PM

Quote:

Originally Posted by cousindave76

I have an 83' 300SD that is long over due for a transmission fluid and filter change. The PO has a record of changing it at about 150,000 miles and the car now has 250,000 miles. I'm going through the whole car trying to get all maintenance items up to date. I've always heard if an automatic trany is overdue for a fluid change to just not do it, it'll go out soon after... is that true? It is shifting perfectly now. The fluid looks good and clean on the dip stick. I'd love to be able to change it out and not worry about it.

Let me know what you guys think and/or your personal experiences with changing an overdue trany.

Thanks!

CousinDave76, that's an interesting question. I can't say that I've ever heard of such a thing. That reminds me of the superstition that cars last as long as their warranty.

There may be some truth to this, but it may be due to the correlation of a long overdue change which causes a problem that prompts the need for a change. I would assume that if someone is prompted to change the fluid because of a "reason" other than preventative maintenance that there is already likely a problem.

cousindave76 · #2 12-10-2009, 04:40 PM

Quote:

Originally Posted by tr1cky

CousinDave76, that's an interesting question. I can't say that I've ever heard of such a thing. That reminds me of the superstition that cars last as long as their warranty.

There may be some truth to this, but it may be due to the correlation of a long overdue change which causes a problem that prompts the need for a change. I would assume that if someone is prompted to change the fluid because of a "reason" other than preventative maintenance that there is already likely a problem.

The only thing I could dig up on performing an overdue change is that the new fluid may knock some built up tarnish loose and cause ports to clog up, leading to failure.

Changing my fluid would be preventive, as my trany is shifting smooth and at the right times. I just don't understand how changing the fluid would suddenly kill it, but I have heard it said so many times that I can't help but be a little paranoid.

tangofox007 · #3 12-10-2009, 04:45 PM

Quote:

Originally Posted by cousindave76

...but I have heard it said so many times that I can't help but be a little paranoid.

And I will bet that you have heard it a lot more times than you have seen it. And the same is true with the people that you heard it from.

barry123400 · #4 12-10-2009, 04:49 PM

There is a small known risk. I would certainly not have it power flushed under normal circumstances. Would just change fluid and filter myself. Or at a reputable garage if unwilling.

At least you can drain the torque converter as well getting the bulk of the old fluid out on these models. The power flush just intensifies the risk greatly in my opinion. Without changing it at all the filter may become too obstructive or restrictive eventually.

Make a point of the method of getting the fill quantity of new fluid right. The archives are your best guide. More than a few have been over/under filled. These particular models seem to want some attention to reading the dipstick applied. Transmission driven till up to it's operating temperature for example before reading.

latitude500 · #5 12-10-2009, 04:59 PM

My vote is to change the fluid and filter ASAP. I picked up my 300SDL from the PO knowing that the trannie needed to have some work on it, and she honestly informed me that she had never changed out the trannie fluid. So one of the first things I did was change out the trannie fluid. Simply as that.

cousindave76 · #6 12-10-2009, 05:25 PM

Quote:

Originally Posted by barry123400

These particular models seem to want some attention to reading the dipstick applied. Transmission driven till up to it's operating temperature for example before reading.

Wow that's the truth! First time I ever checked the level, it took me a long time to be satisfied that I've read the actual level correctly.

cousindave76 · #7 12-10-2009, 05:31 PM

Okay I am going to do it. Berry123400, I am not going to power-flush it. That does sound bad. I'll just drain and drop the pan, drain the torque converter and change the filter.

Tangofox007, I'm sure you are right. I'll not be intimidated by hearsay.

Latitude500, how many miles ago did you change the fluid?

Thanks for the replies!