NovaTime

I'm right about the time to change my trans fluid, and I plan on putting Royal Purple in. I imagine I need to completely drain the entire transmission. what is the best way to go about this for the 4L60E?

BadCompanySS

iTrader: (1)

There's no drain plug so you have to just pull the pan. Usually no clean way to do it. Big drain pan to catch the fluid, clean the pan out, change the filter and gasket and bolt it back up.

SteveC

I would think twice about using sythetic transmission fluid in a automatic, I have read several posts on the boards that it does more harm than good. Somthing about having the transmission start to slip.

JMHO

SteveC

02 SOM WS6

I ran Mobil 1 synthetic in my '98 model Z28 for about 40000 miles. No problem. Century Automotive who rebuilt the transmission in my current car recommends Royal Purple.

Les

NovaTime

I had heard that there was a drain plug, but I haven't gotten underneath it to look. Is it safe to have it pumped out through the transmission cooler at one of the quick lube places? I've done that in my other 4L60E, but i've heard about some problems with doing so.

RPM WS6

iTrader: (3)

You really need to do a full system flush to actually get all the fluid out. I put a truck pan in with a drain plug to make fluid changes easy, and I change the fluid in the pan so often now that I really don't see a need to worry about a full flush anymore. There's always fresh fluid cycling in when you change the pan fluid constantly (I do it about every 3K miles).

Zo6Killer

In my experience if you do regular pan-drops from when the car is new, that should be sufficient. However, if it's been a good long while, the 3-4 quarts you change in a pan drop almost immediately becomes dirty after mixing with all of the old fluid(you can verify this by driving awhile and checking the dipstick-not much if any difference in look/smell). Doing a complete system flush through the coolant lines is the most effective HOWEVER if the fluid change has been neglected doing a complete flush MAY do more harm than good(this occurs b/c the fresh cleaning agents in the new fluid can dislodge built up sludge that can potentially cause trans. failure). If it were me, I would drop the pan, change the filter, then do a system flush. Like I said-if it were me. To each his own.

NovaTime

The truck hit 20 thousand miles yesterday, but I am **** retentive about transmissions after losing a 4L60E I inherited (it had never been changed prior to 100,000 miles). I want to change the filter, and do a system flush like you said, but I am afraid of dropping the pan since it may be near impossible to get that thing back on correctly with no leaks.

NovaTime

I don't feel bad letting it go 20,000 with dealer fluid, especially since I am really not that hard on the truck, but i'd really like to get the royal purple in there.

Zo6Killer

As long as you take your time with the pan, make sure the gasket is lined up, and snug all of the bolts down in sequence and equally, you shouldn't have any problems with leakage. Make sure not to overtighten any of the bolts, though. That could get ugly!
I always put a thin coating of grease around the rim of the pan to hold the gasket in place while putting it back up.