4l60e trans fluid? flush?
 

my 04 silverado last week it was really hot out like 94 degrees i was on a 40 mile run it a hurry (80 to 110mph family emergency) trans temp got up to 240ish only that one time but now im thinking since the truck has 130k on it time to change the filter and flush the trans fluid its dark (not black but dark) i've added a hayden 679 cooler its dropped my trans temps from 195ish on a 30 miles run to around 160ish on the same run (verified true HPturners)

what brand? what type should i go with? dex/merc or DEXRON VI?

i've seen guys taking of the cooler line and draining a couple quarts out then adding and fluid back then reaping it till it was all clean fluid coming out is that ok to do? is there a better way?

plan a ls3/4l80e in the future so trying to get as much out of this trans as i can

My only thought is why it shot up that high was a lot of slipping.

i was pushing it HARD it was down shifting into second A LOT! all the torque management has been removed and shift points changed it now holds second gear till like 90mph while in drive when @ WOT, was running 100mph + probably more then 60% of the time only slowed down to get around traffic then back to 100+ mph engine coolant temps got up to 230ish never seen it that hot before either

the call from my wife startled me i was 40 miles a ways and well i was driving like a 18 year old in a corvette trying to get home (not proud of that but was really worried)

Pan drop, new dex/merc 3 and filter. If after a while the fluid isnt bright red, do it once more. Walmart has the fluid dirt cheap by the gallon.

i dont have first hand experiance but i feel the way that pind thread about using the truck to pump the fluid out the cooler lines is fine as long as you dont run it too dry. i would at least do that to just empty the pan so i dont have to work on trying to spill the tranny fluid everywhere while dropping the pan. i need to get around to doing this my self as i bought my truck at 107k miles and right now am at around 157k miles with no transmission service yet. all tho my transmission temps never get above 150ºf with my trucool 40k.

im the few times i have needed to add some transmission fluid in like when upgrading the cooler or the vette servo upgrade i always used dex vi in it as it is backwards compatible and is a synthetic. not sure how a full change over would go.

If it's never been done, it can't hurt.

I remember around the 140k mark my Blazer's 4L60 seemed a little sluggish. I changed the fluid, filter, and upgraded the servo with corvette parts and all was well again. I had also towed a heavy trailer ~200 miles not long before and had to keep the heater on the whole trip to keep the temps down (in August).

truck usually runs around 200-210 degrees coolant temps, trans seams to run around 190-200 degrees normaly when i towed my vette down to RPM trans (Chicago to Indianapolis) probably 5500lbs tow weight it was around 210 mostly got up to 220 in heavy traffic

i've been thinking its time for a service and flush, my son tells me 190 is hot for trans temp his 94 silverado lq4/4l80e swap runs at 170, on a hot day with aggressive driving he never seen over 190 only has the stock in radiator trans cooler stock trans pan

leaning on DEXRON VI but just want to make sure its ok to use. i dont have a drain plug in my trans pan so not looking forward to the mess that go's along with the filter change :(

I did it before. Pop the return line off the rad and pump out a couple quarts, fill it back up with new fluid and pump out another couple quarts until you see the fresh bright red fluid. This also lowers the level for when you drop the pan ( wout a drain plug ) so it doesnt spill over everywhere. Ive actually sucked a quart out through the dip stick once just to get the level down. Every little bit helps because once you break that seal, its a messy job.

I use the cheapest dex6 I cant find. I also highly recomend the vette servo. to this day that 30 dollar mod made the biggest difference in my transmission. If you have the extra money, now would be the time to put a cooler on it and bypass the radiator.

I run a TruCool 40k. My trans temps have never been that hot while running 130+.

With that being said,

I have a piece of clear plastic tubing with a fitting on the end that I use on the upper radiator line.

I start the truck, watch the line until it starts burbling, shut it down, fill it back up and do it over again until the fluid is a nice red color.