My 2003 Toyota Corolla has 155,000 miles and transmission oil never changed. On mechanic says “yes, change it” Second mechanic, says “too late to change it now without harming transmission”. Who is right?
The good thing is that the transmission oil has likely had an easier life over the last 5 years assuming pure highway at 30k/year. 155k is really late but changing is not a bad idea at all.
The first one.
The old wives tale "too late to change it now without harming transmission" is just that. It comes from the many cars that people drive without ever considering changing the transmission fluid until something tells them that there is a problem. Well, what do you think, the transmission is acting up so they change fluid and a month later the transmission fails. They blame it on the fluid change. Of course it could not be because they failed to change it before it was damaged.
It is never a bad idea to change the fluid, but more important it is a very bad idea NOT to change the fluid, like every 30,000 to 50,000 miles and prevent the problems.
Note: I recommend getting a transmission oil change and dropping the pan and cleaning the pan and the filter. Often this step is missed and while any change is better than non, not cleaning the pan an filter is really foolish.
A man was advised by his physician to have a colonoscopy performed when he reached the age of 50. The man failed to do so.
Each year, the doctor would remind the man of the importance of early detection of intestinal polyps, in order to avoid colon cancer. Still, each year, the man refused to consent to having a colonoscopy performed.
Finally, at the age of 75, as a result of abdominal pain, the man consented to a colonoscopy. The colonoscopy revealed advanced cancer of the colon, and the man soon died.
The people who tell you that doing a very belated fluid change on your transmission would result in failure of the transmission are probably also prone to believing that the belated colonoscopy was the cause of colon cancer in the above-referenced patient.
Like with medical care, timely maintenance is better than maintenance that is not done on schedule. But, even belated medical care and belated maintenance can sometimes save the patient or the vehicle. It may not save either one, but it is still worth a try, and the procedure–in and of itself–is not a cause of death.
What to do if it’s slipping worst then before
Suggest to post your question as a new topic there MichaelG. Click “maintenance/repairs” above, left, then “new topic”, above, right.