Here's an idea for a transmission flush that I got from a friend who's a heavy vehicle mechanic. True, she works on vehicles much larger than what I drive. Like the Caterpillar 972H wheel loader, Caterpillar 336 excavator, Norinco ZTZ99 MBT, International flatbed trucks, etc. But she knows a great deal more than me. What she said to do is disconnect the return line from the radiator and run a hose from the fitting to a bucket or catch pan. Then, run a hose from the return line to a bucket with fresh ATF. Start the engine and let it run until the transmission fluid coming out goes to a nice, clean red color. Of course, make sure the bucket with fresh fluid is kept at a good level, as you don't want to let the system suck in any air. She says doing it this way flushes out the transmission and the cooler in the radiator. Anybody done a flush similar to this?

 

Not sure if the 4L60E pump will suck fluid from a container, or if it relies strictly on the pump to circulate the fluid. I have always disconnected the return line from the radiator and run a hose from the fitting to a bucket. Then start the engine and add fresh fluid in the dipstick tube until it comes out clear in the bucket. Might be worth a try the way you described though. When you're done flushing, drop the pan and replace the filter and gasket. Then refill with fresh DexronVI fluid. Keep us posted. Total trans capacity is around 11 quarts, dropping the pan only removes about 5 quarts, so have plenty on hand. Usually takes 20+ quarts.

 

That may just be the heavy trucks she's used to working on that let you do it that way.


My ATF doesn't smell burned. It isn't perfectly clean, but that's to be expected.

 

Depending on how you do it, that will determine how long the change interval should be. Dropping the pan gets about half of the fluid out, so you need to change it more often. Once you've got it all cleaned out, you can drop the pan & replace the filter every 30K to 36K miles and it will perform well. If you tow anything at all, install the biggest cooler you can find. The factory cooler in the radiator is basically for looks, that's the main reason these things go through transmissions so quickly Cook 'em one time and they're done. ~$1800 to rebuild, or $70 for a cooler, your choice Hayden/Imperial 243012 is a good choice.

 

All 4 gears and torque converter lockup works, doesn't feel like it slips. Don't plan on doing much towing. I still plan on flushing the trans and changing the filter. Btw, which filter would mine take? I've seen the ones on RockAuto for shallow or deep pans. Not sure which mine is.
I know the cost of a rebuild is up there. The alternative is RockAuto. A reman 4L60E is like $1300, about $1063 after core.


Although, my dad has a 93 Chevy Silverado K1500 with the 4L60E, and he got his rebuilt for $850, including replacing the internal computer. The thing is, you have to drop the transmission and take it to the shop yourself.

 

If the TC is slipping, it will set a DTC. If you flush it out and start with fresh fluid & a filter, and then keep up with the maintenance intervals, it should be fine. If you do any mountain driving or towing, you might want to consider a cooler... cheap insurance and it will prolong the trans. The cooler they run, the longer they last.

 

I might just get that cooler soon anyway. My dad did install an external cooler in his after the rebuild, and he hasn't had any problems with his since. His also has the TBI 305ci V8.

 

I change my trans fluid the way the OP discribed and it works great.You add trans fluid a quart at a time as the fluid is pumped out.Have 3 empty gallon jugs ready when you start.Just shut the key off when you fill one and swap in another jug.Add new fluid as you go.Stop when the fluid going into the jug is new looking.This will give you a full fluid change without the flushing effect that can cause problems.

 

So, the transmission will suck ATF in through the return line on the 4L60E?

 

No,you have to add the fluid into the fill tube.