I've been sold on a pan drop vs a flush, I had my pan dropped this morning along with a new filter and Dexron VI trans fluid and man, what a difference!!! Sounds, feels & runs way better...


Lately (before this morning) after long freeway runs or heavy foot action I noticed a whine, slight hissing noise & what sounded like belt slippage suspected to have come from the trans. So far, these noises have gone away with a new filter and DexVI...


I had a flush performed less than 30K ago... I'll be dropping the pan from now on..

 

From what I've read and been told a flush can potentially push the dirt into areas and clog the transmission up. I drop the pan and that's as far as I go. The flush just seems a little too invasive for me.

 

I wouldn't worry about that. That doesn't even make sense. A flush will replace all of the fluid (or like 98% of it) while just dropping the pan only replaces what's in the pan, so it depends on how much fluid you want to replace.

 

There are alot of misconceptions when it comes to tranny flushes. I did research on this about a year ago when I was trying to decide on doing one on my Monte and found that there are two different types of flushes, cooler line flush and pump inlet flush. The cooler line flush is the most common and less expensive but it is the one that has the most ocurrences of problems associated with it afterwards. This is because when the fluid leaves the transmission pump it passes to two different pressure regulators. One regulator supplies fluid at one pressure to the transmission itself that operates the pistons and controls gear shifting. The other is supplies the torque converter and the transmission cooler. So you can see that all the fluid leaving the pump does not go to the cooler. A bunch of it is cycled through the transmission and dumped back to the pan without going through the cooler. This type of flush machine does not remove all the old fluid, but it continuously dilutes it down with new fluid. It never really removes all of the old fluid. Also, they sell the supposed benefit that they do not have to drop the pan and change the filter like that is a benefit.

With the pump inlet flush, it attaches to the pump intake after the pan and filter is removed. This machine only supplies fresh new fluid to the pump intake and as the fluid passes through the transmission it dumps out to a collection tray and never goes back through for a second pass. All of the old fluid and crud is GONE and replace with fresh new fluid. After the service a new filter is installed, the pan replaced and then it is topped off with new fluid to the proper level on the dipstick.

It will be easier to find a place that does the cooler line flush, but worth the effort by finding one that does the pump inlet flush.

Hope this helps

 

I'll always drop the pan.

 

I agree with Fox in that I'll always just drop the pan. It's been done for years that way with no problems.

 

I wasn't saying that dropping the pan would cause problems. But it doesn't get anywhere near all of the fluid out.

 

I don't think anyone was thinking that. But yeah, I agree with you. IMO, dropping the pan only is like telling your son to go take a bath after his sister took a bath and only drained half the water and then filled it back up with fresh water. That's just wrong!

 

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