transmission flush

[silveradoking]

hey you guys.. i have 80,000 kilometres on my truck. i read that the it is best to change your fluid around 50 k, yet due to ill fatedness i went to the local parts shop and bought what i need and changed my transmission fluid. i changed the filter and those stupid small plastic pieces. which were a tough one i then used the ol' unhook the cooler lines, start the truck and then pour method to flush the old crap out. i then put in about 15 litres of some cheap transmission fluid and let it all come out. then i poured in about 13 litres of the good stuff from royal purple. i then also installed both a b&m trans cooler which i got dirt cheap and i b&m transmission pan for about 5 litres extra. i turned her on and she shifts so fine, i am very pleased. i probably don't recommend that people go through what i did... but i am that type of a guy.... o well..

[jeverett]

Glad it all worked out for you I'm scared to change mine with all my miles on it.

[busta]

well you got balls! cool. good job on the cooler and deep pan! should have got the corrvettte shift kit. oh well next time.

[Rhymingmechanic]

silveradoking--It sounds like you got all the old fluid out and replaced it with the good stuff without having to pay for a shop flush. What year is your truck, and do you remember which line pumped fluid from the trans?

I took the easy way out. Since the pan has a drain plug, I drained and filled with Mobil 1 twice over 2 weeks, then dropped the pan, changed the filter, and filled with M1 again. That was at 35k miles, and I plan to drain the pan about every 30k from now on.

I have seen a lot of internet posts about problems with flushes on high-mileage or neglected transmissions. The theory is that the flush stirs up crap from the pan that causes problems. Or you could be like my friend who had his Neon trans flushed, and then called for help because it was shifting funny. We added 3 quarts because the guy who flushed it didn't tighten the line.

But the best thing anybody can do for their trans--especially if the fluid has never been changed--is change it. Trans fluid breaks down with use just like any other oil, and will eventually gum up the valves and solenoids. And the longer it goes without a fluid/filter change, the more metal particles and clutch materials build up. GM's overdrive trannies are especially hard on fluid because they make more heat than the old 3-speeds. All the more reason to add a cooler and do regular fluid changes. So if you have high miles, stay away from flushes, but change the fluid and filter! There's no reason not to, especially on the trucks with drain plugs.

[wafrederick]

Flushing a transmission is a big no no even properly done.Dirt get inside the valve body and causes problems.My father know someone has his own transmission shop that loves getting them in with problems because the transmision was flushed.He cleans the valve bodies out because of the transmission flush.

[White Lightening]

What I don't understand - is why aren't transmission fluids changed after say 5,000 or 10,000 miles the first time?

With my engine oil - on a new engine - I changed at 1,000 miles even though the dealership said 3,000 (standard length). But I did it myself at 1000 (like I have done with bikes and cars since I was a kid). My engine oil showed considerable signs of engine break -in, just like you'd expect - and certainly I wouldn't want that running around inside the engine another 2,000 miles. It doesn't mean I wouldn't change every 2500 or 3000 now - but the break in period on moving parts is SOOOOO important (get it broke in then get the fluid changed).

But I never hear it done on transmissions - which have at least as many moving parts (and costs to repair) as an engine does.

Any opinions on that first transmission fluid change being more important than the others?