07 Trailblazer ATF flush/change

[BuzzStPoint]

Been wanting to change the trans fluid in the truck, pulled a trailer a week ago and had some codes come up saying transmission component slipping. After that I had lazy shifts, and jerky shifts.

Pulled return line and fired up the truck and spit out all the fluid. Dropped pan and cleaned the shift manifold. Flushed by starting truck up and pouring fluid in till it came out the return line nice and red.

Truck shifts better. Seems 1-2 is a bit lazy, but the rest are quick and smooth. Also have a high pitched whine or whistle sound coming from the trans. (Was there after the trailer pull) . My wife says I'm crazy but I can hear it.

Materials used.
Pioneer filter and gasket.
11qts of Oreilly Dex IV

 

[oldhp]

Add a 10oz bottle of LUBEGARD Red. Stuff works great.

 

[Chris142]

I had a customer come in with a running hot complaint on one of those trucks. The trans cooler had leaked and filled the trans up with coolant. I ran 24qts of dex6 through it it then changed the filter. Fluid was now looking good. Trans failed 6 weeks later anyway.

 

[Falcon_LS]

Originally Posted by oldhp
Add a 10oz bottle of LUBEGARD Red. Stuff works great.


I add half a quart, overkill for sure, but a ton of stop and go in 120+ F weather in the summer months in particular. Also got a Derale cooling pan with an extra 2 quart capacity, plus an external Long Manufacturing air to oil cooler.

 

[JTK]

How many miles on that 4L60E?

I *think* GM had that sun shell issue fixed on that trans by 2007, but that could be non-related anyway.

 

[MolaKule]

You might want to do another D&F after using LubeGard since varnish will get suspended after the cleaning.

 

[DoubleWasp]

Originally Posted by Chris142
I had a customer come in with a running hot complaint on one of those trucks. The trans cooler had leaked and filled the trans up with coolant. I ran 24qts of dex6 through it it then changed the filter. Fluid was now looking good. Trans failed 6 weeks later anyway.


Coolant is universally a death sentence for transmissions. You did the best you could.

 

[BuzzStPoint]

Originally Posted by JTK
How many miles on that 4L60E?

I *think* GM had that sun shell issue fixed on that trans by 2007, but that could be non-related anyway.

In about 100 miles it will be rolling 187,000 miles,
Not sure if that's how many miles are on the trans. A well as the truck runs, I would think it's the original trans.