My friends 2007 chevy uplander had very burnt/black transmission fluid and was displaying a “transmission fluid hot” message on the dashboard. We figured there was nothing to lose by changing the old fluid with maybe a 10% chance it might fix the problem…
So we did a drain and fill and filter change on it and upon checking the dipstick after refilling with 7 quarts of new fluid, the fluid on it was now a medium dark red but no longer black. We drove it around for no more than 15 minutes before the same warning message “transmission fluid hot” appeared on the display. Pulled over and the fluid was burnt black again. What would cause new fluid to become damaged/burnt again in just 15 minutes of driving? The burnt fluid definitely explained why the transmission was overheating before the fluid and filter change but to me there’s no clear explanation as to WHY the brand new fluid is burning up so fast…sure burnt fluid causes overheating but why would it still overheat with new fluid and burn it up?
Clogged trans. cooler, lines, crimped lines? Has any of this been checked. Or maybe just plain old fashioned failing/failed trans.
Burned fluid is the result of overheating, not the cause.
Something is causing the transmission to overheat, slipping or dragging clutches. The transmission cooler might be clogged with torque convertor clutch material.
Or the transmission could be on its last legs.
The fact that the fluid was burnt/black when you changed it is a sign of neglect.
When you drain the transmission fluid, only about 30% of the fluid is removed. The rest is still held in the torque converter, transmission cooler and lines, and the valve body.
I would suggest getting the transmission fluid flushed so 100% of the fluid is changed.
And then cross your fingers.
Could the remaining 70% of the old fluid that’s burnt cause the new fluid to overheat/burn simply because it’s not diluted enough? I’m just trying to calculate if it’s worth spending $250 for a tranny flush or just sell the car as is with the overheating trans
Shouldn’t that decision be made by the owner of this vehicle ? What ever you tell them to do will be in the ’ No good deed goes unpunished category ’ .
Ultimately it will be his decision i’m asking for advice on his behalf
Burnt fluid does NOT cause overheating. Overheating causes burnt fluid.
And I gave you my advice.
Then he needs to have a real transmission shop look at this vehicle. Selling like it is will be difficult .
Selling will be easy, they buy vehicles in any condition.
The transmission is near the end of its life and it’s more than likely caused by not servicing the transmission regularly in the past. Changing the fluid after it’s burned black is too late.
A converter stall test could be performed but IMO this would just verify the obvious.
I tore down a 4l60e and the 3-4 clutches looked like potato chips. Smoked. But that’s a common failure on a 4l60e. Black fluid is not good.
The clutches are burning. It will start acting up soon