Hi All,     I've got 3,000 miles on the truck I bought used last August.  I was replacing the reverse light switch and spilled quite a bit of fluid and it was dark.  So I was thinking time to get the fluid changed and the bands adjusted.  So my question is Change or Flush??

 

TIA

Michael

If I didn't have any idea how many miles were on the fluid, I'd do a flush. Regular fluid changes without a flush are fine too, but keep in mind you are only getting half the fluid (estimated), so the new is still diluted with the old.

Edited March 31, 20196 yr by kzimmer

My trucks were held hostage by dealers therefore they both got a trans flush, which I've been told is not a good thing causing the dirt and wear metals to get stirred up. I've not had any problems though. I change the filters and whatever drains out every 30,000. If I tow heavy, and slightly burn the fluid ( I watch the temp gauge and keep under 180*) I just drain the fluid and change that w/o doing the filter until I reach the 30,000 mile interval, then I change the filter too.

Edited March 31, 20196 yr by JAG1

Thanks that answers my next question.  How often do you change it!

 

Thanks!

Michael

Edited March 31, 20196 yr by int3man

Every 30,000 miles for fluid and filter and adjust the bands, but I probably won't always adjust the bands unless they need it. Change the fluid ASAP if you get it too hot and burn it.

I pull the return line off the cooler or a line off the exchanger on the side of the block since its vertical and run for second to pump the fluid out of the converter. 

Drop more fluid in it then repeat until fluid comes out clean. Its easier with two people. You dont want to run it dry. 

Youl need about 16quarts.

 

If done right youl see it or have a helper watching to see when the bad grungy fluid turns to a good red color

 

 

 

 

Done that method a time or two for others...

 

Flushing is the best way to exchange all the fluid but the pan still has to be removed to replace the filter and adjust the rear band. 

 

You need to be careful with a severely neglected transmission.  When the fluid is so old that it is black I don't recommend a flush.  I've had several people, over the years, call me saying they took their car in for a trans flush and 2 days later the transmission was junk.  If the fluid is that bad I would drop the pan change the filter and refill.  If the transmission is still holding together after 10k miles drain and refill then every 30k after that. 

59 minutes ago, IBMobile said:

You need to be careful with a severely neglected transmission.  When the fluid is so old that it is black I don't recommend a flush.  I've had several people, over the years, call me saying they took their car in for a trans flush and 2 days later the transmission was junk.

 

See I've heard this before, and I've always thought it was because people don't take their transmissions in for a service UNTIL there are problems. So the thing is already toast, they are just hoping fresh oil will fix it. And, of course it doesn't. Soon after, things stop working completely, and the flush vets blamed. But maybe that's not true, just a thought. I would think that it would also be a bad idea to flush before removing the pan and cleaning out sludge. As someone said, it may stir things up.

In my mind it serves them right. You dont drive 150k and never service your tranny.

 

That would be like never brushing our teeth then bitching when they rot and fall out.