Is it true that flushing the tranny at high miles can do more harm than good? And is it just the flush that's a problem and not a drain and fill? I have 80k miles on mine and think its time I did this maintenance. I just replaced all the belts and had the coolant flushed for the first time. Thanks.

 

thats an ancient myth, started by idiots.
no, flushing your trans at 100k is not harmful. Waiting until 100k to maintain your trans is the harmful part.

 

A flush at a 100K is gonna bepushing it depending on how hard its been drivin. Should have it done around 50 or 60 to be safe. What happens is the higher the mileage on your tranny the more metal particles that will be in the tranny also. When you flush it your gonna stir them up especially in the torque converter. It wont exactly ruin your tranny but it will cause your valves in your valve body to hang up and leave your stranded. Then youll take it to your trusted transmission shop and they will tell you you need to rebuild it because there is no way there gonna let you outta there without spending at least $1500. Not to mention most tranny shops only know how to replace and rebuild not diagnose or troubleshoot. There will be some on here that call bull**** on that but thats the skinny on it.

 

no, as I said, thats an ancient myth started 40 years ago.


it is completely harmless to flush your trans at 100k. Its far more harmful to wait until 100k to finally service your trans.

 

{edit}

double post.

 

I'm gonna go with manybrews... to an extent.
As long as proper routine maintenance has been done, and the tranny be ing previously serviced, then you're ok.
But yet, i've seen firsthand where a vehicle with 120k that got tranny serviced every 45k, after the service at 120, a few weeks later the trans failed.

 

it has nothing to do with changing the fluid.


I wish I knew where people picked up silly information like this... Probably from their grandfathers when something like this happened to their 52 mercury.

 

Isn't there a concern that a flush on the filterless 8G trannies (where the tranny has 100000 miles and the service history is unknown, my current situation) could potentially loosen clutch material and metal particles which could get picked up by the pickup screen, thereby clogging it and causing these catastrophic failures that seem to be mentioned quite a bit.That is, unless these are just old wives tales. Manybrews, you seem to be adamant that this is not a concern?

 

it is absolute nonsense.


If there is a failure of the trans, its due to previous neglect, not from replenishing the fluid (which needs to be done, as the additives do wear over time).

 

Well, I did the fluid exchange where theyreplaceall the old fluid at the dealership right after I bought it a few months ago. Essentially the flush without the chemical. It's shifting good. Maybe next time I'll let them use the chemical.Thanks for your feedback.